Bruder Piggyback Forklift

[Zabco]

About two years ago I was watching a video clip of a RC truck meet in England. If I remember correctly it was in a link posted by Bo Wallen of his trip there to the UK Nationals. Part way in there were a few seconds showing a small "piggyback" type forklift loading a flatbed trailer. I was really fascinated by this little forklift. They are very common where I live and I had never seen a working model of one before. Here is a screen capture of the forklift from the video.

https://i.postimg.cc/HkxjqYzQ/Moffett-forklift-model-2.jpg (https://postimages.org/)

I thought it would really be neat to get one of these and see if I couldn't convert it to full RC. I really had no idea where to start. It appeared to be sort of toyish in looks so I suspected it might be made by Bruder. Sure enough, about two months later I was in a Tractor Supply store and happened to walk down their toy aisle. Out of the corner of my eye I saw a Bruder Mack box truck labeled for UPS and hanging on the back of the truck was the little forklift.

https://i.postimg.cc/vHXc2grY/2828-Main-5.jpg (https://postimages.org/)

Apparently the forklift is only sold as a set with another truck and I didn't feel like spending $100 just to get the forklift, especially as I had no idea if I could do the conversion. I went to Bruder's web store and found that the forklift was listed as a 'spare part' for the UPS truck and could be purchased individually that way. Price for just the forklift was $21. That was cheap enough that I bought two of them, one to chop up and experiment on and figure out how to do the conversion and then a clean one to do the final version with. If I couldn't make it work I wasn't going to be out much money and would have the fun of trying.

I started by searching the internet to see if I could find examples of other conversions and see if I could get some ideas on how to proceed. Ideally I would find a build article or 'how to' from someone who had done the conversion. No such luck. After many, many hours of searching I was only able to find a few photos and very short video clips of a couple of these in action. I was able to get a couple of ideas on how to build but was still left with a lot of questions. The other thing I noted was that some of the conversions were sorta crude. If you look at the photo of the forklift from the video clip you can see that what appears to be a battery pack and other parts are sticking out of the body in several places. I didn't want that. When I do a Bruder conversion one of my primary goals is to keep the body looking as much like the original as possible. If you look at one of these Bruder forklifts it is very apparent there is not much room inside for a battery, motors, servos and all the other electronics needed. That would be the biggest challenge.

After months searching and looking at the model I was just about to decide to just tear into it and see what I could do when I finally hit some pay dirt on the internet. Last winter when searching again I came across a posting on the Bruder Facebook page showing a conversion that I thought looked really good. The author posted a number of photos showing some of the details of his work and that was the info and inspiration I needed. He also said that he would post his 3D print files on Thingiverse if anyone wanted them. I won't list his name as I don't have permission but you can find the article and print files by searching 'Bruder UPS forklift' on both Facebook and Thingiverse.

Using this information as a start I was able to create what I think is a very nice, fully RC controlled model of this forklift. If there is any interest in this conversion process I will write up a series of articles on how I did mine. This will be some work on my part and will take time. If you want to see how I went from this:

https://i.postimg.cc/N02F0dWF/DSC-9180a.jpg (https://postimages.org/)

to this:

https://i.postimg.cc/4xSnZD2j/DSC-9164-0223.jpg (https://postimages.org/)

Let me know. Yes, it's now blue because a) I had 3D printed parts that needed to be painted and I don't know of a good paint match for Bruder's red, b) a lot of the piggybackers I see around here are blue, and c) I really like blue.

[jerry56]

Ab so Lootly... I have the UPS set, got it at a toy show for $50... The forklift is on my "to do list" I think somebody here did this one but I can't remember who.... and I know Frizzen has done other types...
Lets see how this goes...

[frizzen]

Oh wow, that's gonna be really cool to see getting converted!!!

How's the stability? I mostly see that type hanging off of flatbeds delivering building supplies.
Did you build the ability for it to stow onto the truck for transport?

[dremu]

Oh, write away! Conversions are in many ways much harder because, as you note, the thing is designed for looks and not to fit all the stuff inside that a full RC needs.

Heck, the only conversion I've done is from a vintage wired RC to modern wireless (admittedly with some other work), and getting the battery and whatnot to fit was a nightmare. I've gotten spoiled doing scratch builds and adjusting the shape or dimensions as required to get the desired components to work.

Also, as obvi you're aware, forks are bloody complicated. I did one and while it works well enough, the scale and appearance suffer a bit for that.

Finally, this one looks like the tines are adjustable-spacing, which was a luxury I couldn't squeeze into mine. I had to have fixed-spacing tines on a carriage that shifted side-to-side. I'd love to see how you made all the moving parts ... well, move :D

-- A

[Zabco]

Did you build the ability for it to stow onto the truck for transport?

Yes it is capable of lifting itself up. One of the first things I tested when I got it fully assembled. I will have to modify the rear of my flatbed trailer so that it can haul it.

[Zabco]

Finally, this one looks like the tines are adjustable-spacing, which was a luxury I couldn't squeeze into mine. I had to have fixed-spacing tines on a carriage that shifted side-to-side. I'd love to see how you made all the moving parts ... well, move :D
-- A

Yes the Bruder has adjustable tines but they have to be moved manually. And yes, I will start posting my build of this in the next day or two.

[Zabco]

Bruder Piggyback Forklift Build part 1

OK, a few caveats first. Like any of these Bruder conversions there are a number of ways to do it. This is the way I did it with the parts I had, and I'm sure there are other/better ways. Experiment and have fun. Post up your builds if you do something different.

Second, I will not build one for you and I will not provide parts. As stated in my first posting I used the Thingiverse parts as the base for my build. And while I ended up only using a few of those parts the others that I made were based on them. And while I am fortunate in having a fairly well equipped shop to work in I think all the parts could be made with hand tools and/or a simple 3D printer.

Lastly be aware of the limitations of this model. This is a lightweight toy. Even with all the RC gear stuffed inside it will tip over very easily, especially if the mast is all the way forward. I just wanted to be able to load my flatbed with pallets holding four scale oil drums. These weigh about 5.3 ounces or 150 grams. My model will handle this but I had to add some lead weight to the rear wheel to do so. The mast and forks will also bend to some degree under load. So you are not going to be able to lift the larger loads that other RC forklifts can but it is still a great build.

Lets get to it

The first part, and often the hardest with these conversions, is simply taking the dang thing apart. This forklift is no exception. Bruder intended these toys to hold together through all the beating a child could give them.

(EDIT: moved this paragraph here from part 2 because if you don't do this first you can't take the model apart)
The first step, if you haven't already done so is to remove the rear drive wheel from the model. This is easily accomplished by simply cutting the top knob of the steering control off right where it meets the upper body.

https://i.postimg.cc/K8FNmKj3/DSC-9181-0036.jpg (https://postimages.org/)

The drive wheel and support mount should fall right out the bottom. Carefully pull the wheel/tire off its axle and set it aside. The rest of the mounting will not be used and can be discarded.

I used several small and thin screwdrivers and picks to pry locking tabs back and try to pull a joint open. I started at the front of one arm and just worked my way around using toothpicks to shove into open joints to keep them open. Go slow and easy and it will come apart. One good thing about this model I found is that the wheels will pull off their axles fairly easy without being damaged.

https://i.postimg.cc/KjVwX31K/DSC-8736-0036.jpg (https://postimages.org/)

I figured that I was probably going to have to put this thing together and take it apart a lot of times before getting done and I didn't want to go through that disassembly headache every time. Plus making it easier to do maintenance/repairs in the future. So first thing I did was to take every locking tab;

https://i.postimg.cc/rpCBdpPb/DSC-8737-0036.jpg (https://postimages.org/)

and sand them flat.

https://i.postimg.cc/rwWXkjCq/DSC-8738-0037.jpg (https://postimages.org/)

Then to hold the model together I drilled a hole through both top and bottom pieces at every location where there was a locking tab and installed a #2 sheet metal screw.

https://i.postimg.cc/50sD3R1S/DSC-8739-0038.jpg (https://postimages.org/)

DO NOT drill/screw the two locations in the front center as I have here. I didn't think of it at the time, but once the mast assembly is put back in place you can't get to these. Don't need them, the other six screws are plenty.

Prying the tabs from underneath I then removed the ROPs and driver seat.

https://i.postimg.cc/26kPnDp5/DSC-8749-0048.jpg (https://postimages.org/)

Now is probably a good time to go ahead and start cutting away a lot of the internal plastic that has to be removed to make room for all the RC parts. Keep in mind that I removed plastic at different times during my build as I was working on trying to fit a specific component. You will see in future photos this progression of removal. But you can go ahead and remove almost all of it now. The body remains quite stiff and strong so there is no real risk of breaking it without all it's internal bracing.

https://i.postimg.cc/Y09BBw8P/Remove-Plastic-Bottom.jpg (https://postimages.org/)

On the bottom half you can remove all the parts with the green outline. A Dremel or similar tool is the easiest way to do this. Just cut/grind away everything until you reach a flat surface. Go slow and easy to avoid the tool kicking away and damaging something you don't want cut. The area outline in yellow you may want to hold off on for the time being. I had to lower this area to clear the servo arm I used to move the mast assembly in and out. Depending on your servo/mount combination you may not need to. Finally the two parts outlined in white. Be careful not to cut/grind/damage them in any way as these are the rails the mast assembly slides on.

https://i.postimg.cc/mk5fb65g/Remove-Plastic-Top.jpg (https://postimages.org/)

On the top half of the model cut/grind away all the areas outlined in green down to flat surfaces they are attached to. Again, you may want to hold off on cutting away the cross shaped part outlined in yellow. The end of this part is a guide that keeps the mast assembly from tilting forward under load. Unfortunately this area is also about the only place you can fit a battery pack. I ended up having to remove this part and found it's loss to not be a problem. Comparing my finished model to the the original I found that the amount of up/down movement in the mast assembly is about the same.

Moving to the outside of the model, cut off and sand smooth the mast grabs at the front.

https://i.postimg.cc/XNDTBmsV/DSC-8878-0154.jpg (https://postimages.org/)

Need to clip away a bit where the right arm extends from the body to clear the area where the mast extend/retract rod will have to be. You may want to wait on this till you have your servo and control rod in place so you can see exactly where and how much to remove.

https://i.postimg.cc/wT1YWg1y/DSC-8881-0157.jpg (https://postimages.org/)

I had to cut an opening as shown for the wiring from the mast lift motor and tilt servo to enter the body. Again you will probably want to wait until you know exactly where and how big to fit your build depending on your components.

https://i.postimg.cc/1X42Yr3h/DSC-9104-0175.jpg (https://postimages.org/)

Lastly, for this posting, I like to install a master switch to control all the power on my models. I typically use a miniature 6A rocker switch. I thought that a good place for it would be under the operators seat and so cut the appropriate sized hole.

https://i.postimg.cc/7LkvYzm0/DSC-9105-0176.jpg (https://postimages.org/)

That's all for this time. Have fun.

[jerry56]

Good point.. you got to know your toys limitations.... people forget that sometimes...
I've looked at the files for this on Thingiverse but haven't done anything with them yet....
Conversions are fun when you take a static toy and make it work....

[Zabco]

Bruder Piggyback Forklift Build part 2

I had to wait for a bunch of the parts I needed for this build to arrive so decided to start by making and installing the rear drive and steering assembly. This assembly requires printing out the 'UPS_drive_motor_arm' and 'UPS_steering_mount_V2' parts from the Thingiverse files. In this posting I am just going to cover the installation of the steering mount.
This photo shows the steering mount and battery cover on the 3D printer build plate.

https://i.postimg.cc/cHVR2CPH/Print-Parts-3-0242.jpg (https://postimages.org/)


You will note that the steering mount is not symmetrical and the slot for the servo is not centered. How to install this part and keep the servo axis centered in the forklifts wheel well? Here's how I did it.

The mount is designed to use a standard 9gr micro servo that is inserted into it's mounting slot from the bottom. You could just install the servo and eyeball the placement but I wanted to ensure that it was dead center. This photo shows the parts I used.

https://i.postimg.cc/GmJXDFVj/DSC-8740-0039.jpg (https://postimages.org/)

At the top is the steering mount and a micro servo. In the bottom is a 3D printed copy of the servo and a ring. You don't need the servo copy but I already had some left over from another project where they were used to help design the layout of hydraulic components. Using the copy servo kept dangling wires out of the way. The ring was sized to take up the difference in size between the steering mount hole in the back of the lift and the neck of the servo. The ring, servo and steering mount were put together and then placed over the hole in the back of the lift.

https://i.postimg.cc/Hny2kXbX/DSC-8744-0043a.jpg (https://postimages.org/)

This ensured the axis of the servo was centered in the wheel well. Using a straight edge I then transferred the location of the steering mount sides down to the lift body. I then used a small square to draw out the straight cut lines on the floor of the lift.

https://i.postimg.cc/qBPwZDdL/DSC-8745-0044.jpg (https://postimages.org/)

Next I printed a plug sized to fit in the hole of the lift with a center mark drilled in it. This is used to hold one arm of a pair of dividers or a compass set to match the radius of the curved part of the steering mount. The divider or compass can then be used to scribe the curve that needs to be cut out. This next photo shows the resulting guide lines for the cuts that need to be made.

https://i.postimg.cc/8kJw4Qxc/DSC-8746-0045.jpg (https://postimages.org/)

The base is then cut out using whatever method you prefer. I used a short Xacto saw blade on the straight cuts and a length of thread to cut out the curved portion.

https://i.postimg.cc/XJhLWQBn/DSC-8747-0046.jpg (https://postimages.org/)

The printed steering mount can now be glued in postion as shown below. I used a two part epoxy.

https://i.postimg.cc/s2TK6VVQ/DSC-8748-0047.jpg (https://postimages.org/)

The reason the curved part of the mount is on top of the floor and the straight part is underneath is because there is a portion of the top half of the lift that hangs down and when installed will almost touch the floor just to the left of the mount. More about this later on.

After letting the epoxy cure fully, I installed the servo and then placed the upper half of the model in place to check on fit. As can be seen in the next photo the thickness of the mount is thicker than the floor section removed was and will not allow the two halves to come fully together.

https://i.postimg.cc/PxNy0Bx6/DSC-8752-0051.jpg (https://postimages.org/)

Simple fix, just mark on the upper half where the edges of the mount hit and then cut/file/sand a notch just deep enough that the two halves will come fully together.

https://i.postimg.cc/SKSDfXpb/DSC-8753-0052.jpg (https://postimages.org/)

That left a nice big gaping hole in the top of the lift where the manual knob used to be.

https://i.postimg.cc/pXKCNQWt/DSC-8754-0053.jpg (https://postimages.org/)

Again, a fairly simple fix. Measure the diameter, transfer to a flat piece of styrene and cut out a disc to glue in place over the hole.

https://i.postimg.cc/bvw92KQz/DSC-8755-0054.jpg (https://postimages.org/)

And then file and sand the rim down flush with the disc.

https://i.postimg.cc/7LtM1mVS/DSC-8756-0055.jpg (https://postimages.org/)

Just having that plain flat disk there kind of bothered me after looking at it for awhile. On a real lift why would it be there? Well maybe we can make it look like an access plate for maintenance. I used to be heavy into model railroading years ago and still have a lot of modeling parts for rail cars left over (never throw anything away, right). Looking through that stash I came across some nut/bolt castings that I thought would dress up that plate and make it look like it could be removed. Measured the outside diameter of the plate rim and printed up a disc with evenly space holes to use a a drilling template.

https://i.postimg.cc/t45zJXnS/DSC-8765-0064.jpg (https://postimages.org/)

Drilled holes of the proper diameter to match the castings. Inserted the nut/bolt casting into place and glued from the backside with CA. They are square headed nuts but they are so small that its not really noticeable and I think made a big difference in the appearance of the model.

https://i.postimg.cc/mDc3mCXJ/DSC-8768-0067.jpg (https://postimages.org/)

That's all for this post. I the next one I'll cover the drive motor assembly and installation.

[Zabco]

Bruder Piggyback Forklift Build part 3

In this part I'll show how I assembled the steering and drive motor assembly. I used a common N20 motor/gear box. The one I used was rated 12V and 100rpm. I used a 12V rated motor because I initially was going to use a 3S LIPO battery and ESC.

If you haven't already you need to print out the 'UPS_drive_motor_arm' from the Thingiverse files. The N20 motor was a perfect friction fit in mine and required nothing else to hold it in place. Sorry, don't have a photo just showing how the motor fits into the arm but it's pretty obvious once you see the part.

There is a recess in the top of the arm that fits over the shaft of the servo and a standard servo arm screw is used to secure it in place.

I had a problem with the arm slipping on the servo and not staying in place. To fix this I put the arm in my small milling machine and cut a flat bottom hole with a 1/4in cutter.

https://i.postimg.cc/V5PCc92h/DSC-8853-0135.jpg (https://postimages.org/)

I then took an old, damaged servo arm I had and cut the center splined hub out and epoxied it into the hole I just milled.

https://i.postimg.cc/G3VV6Mmp/DSC-8854-0136.jpg (https://postimages.org/)

This locks the arm to the servo shaft and no more slipping.

Next was to mount the wheel/tire to the motor shaft. The shaft from the gear box is 3mm in diameter and is a loose slip fit into the hole in the hub of the wheel. The hub though is longer than the motor shaft so that when placed on the drive shaft the tire is not centered under the servo shaft. To fix this the hub has to be shortened. To determine how much to remove I took a thin piece of plastic, placed it alongside the motor shaft and marked it to use a length gauge.

https://i.postimg.cc/k5JpWzfT/DSC-8840-0124.jpg (https://postimages.org/)

There are a number of ways to cut back the hub, I used my small mill after clamping up the wheel/tire in a 3-jaw chuck.

https://i.postimg.cc/SRMM5118/DSC-8838-0122.jpg (https://postimages.org/)

Then I would mill off a little bit of the hub, check the remaining length with the gauge. Kept repeating this until the mark on the gauge was fully exposed.

https://i.postimg.cc/P5kc5PZs/DSC-8839-0123.jpg (https://postimages.org/)

This ensured that the remaining hub was just slightly shorter than the length of the motor shaft and would not rub against the gear box. The tire ended up being almost completely centered under the servo shaft. It's just a little off but not enough to be a problem. If you want it to be completely centered then you could remove a little bit off the end of the drive shaft and shorten the hub just a little more. If you try and drill the hub a little deeper I think you have a good chance of just drilling right through the front of the hub which would ruin the looks. I didn't think it was worth the bother to do.

As mentioned above the motor shaft is a loose fit into the wheel hub. Since the original axle was pretty much a friction fit I figured that would work here as well. There is a flat on the motor shaft and I used CA to secure a thin strip of styrene on it.

https://i.postimg.cc/pVp3GNx7/DSC-8842-0125.jpg (https://postimages.org/)


After the glue cured I carefully sanded the plastic down until I got a nice snug fit of the hub over the drive shaft.

https://i.postimg.cc/3JGVhgkF/DSC-8843-0126.jpg (https://postimages.org/)

Soldered the power wires to the motor and inserted the motor into the support arm.

https://i.postimg.cc/kgFH6qFV/DSC-8844-0127.jpg (https://postimages.org/)

On one side of the support arm is a groove. I used this to route the power wires around the back side of the arm. To hold the wires in place I used a few tiny eye screws. These are used to hang pictures and are available in craft stores.

https://i.postimg.cc/ydWpb9q9/DSC-8855-0137.jpg (https://postimages.org/)

I then installed the assembly into the mounting plate installed earlier. The servo has to be inserted from the bottom at an angle and then rotated into final position. I was able to do this as a complete assembly but you could also just insert the servo first and then attach the arm and then insert the motor

https://i.postimg.cc/TPtH00sf/DSC-8856-0138.jpg (https://postimages.org/)

Next was to hook it up to a battery and receiver and test the functioning. It worked well but only turned 90 degrees left and right. Well that's the 'normal' range of motion on typical servos. The real world forklifts like this though are capable of ZTR or Zero Turn Radius. That's what I wanted for this model also. The classic fix to get more rotation is to take the servo apart and insert a couple of resistors into it's potentiometer circuit. Yea, that's a pain to do in a standard size servo. I really didn't want to try on a micro servo like this. Fortunately I was using a new Radiomaster TS16S transmitter for this build. It allows me to extend my endpoints out to 150% so I could get more servo rotation without having to modify the servo. It won't get me all the way to a full 180 degrees but it's close enough.

https://i.postimg.cc/4dM2kdZ0/DSC-8857-0139.jpg (https://postimages.org/)

https://i.postimg.cc/QCT4X3dd/DSC-8858-0140.jpg (https://postimages.org/)

That's all for this post. In the next I'll start in on the lift mast.

[frizzen]

That looks like it's a really slick and well thought out conversion!

[Zabco]

That looks like it's a really slick and well thought out conversion!

Yes, the individual who designed these parts did a good job on them. I was really glad to find them.

[dremu]

Dayum, that came out well. Coupla things I hadn't thought of there, as I blithely assumed the front/fixed wheels would be the driven ones. In your pix, though, I see where there prolly isn't room for even an N20 (maybe a right angle one, maybe) to fit! Fitting one into the steer side is a trick.

Also, dayum on the TX. My beloved Flysky FSi6, even with the tweaked firmware, only goes to +/-120. 'Course I usually use Arduinos for servo stretchers/reversers, but in a conversion like this you just don't have the luxury of that kind of space. And yeah, modifying a 9g is brutal (no way at my age I could even see in there :D )

One thought on the fork tines drooping. I'd originally designed mine at maybe 100mm, which held fine, but didn't reach across the trailer. I then arbitrarily stretched them out to like 150mm. That let me drop a pallet onto the trailer, but deflected something fierce in doing so. I ended up doing a notch down the length and gluing brass rod in there

http://www.slosh.com/rc/fork/IMG_3200.JPG

May or may not be applicable to your setup as mine's 100% 3D printed, and I think a bit bigger (== easier to fiddle with), but since you have the mill you might be able to route a channel down the bottom and fit some reinforcement in.

Finally, did the taillights come with the Bruder, and are they stickers or like translucent lenses or something?

-- A

[Zabco]

One thought on the fork tines drooping. I'd originally designed mine at maybe 100mm, which held fine, but didn't reach across the trailer. I then arbitrarily stretched them out to like 150mm. That let me drop a pallet onto the trailer, but deflected something fierce in doing so. I ended up doing a notch down the length and gluing brass rod in there

May or may not be applicable to your setup as mine's 100% 3D printed, and I think a bit bigger (== easier to fiddle with), but since you have the mill you might be able to route a channel down the bottom and fit some reinforcement in.

Finally, did the taillights come with the Bruder, and are they stickers or like translucent lenses or something?

-- A

Good idea, I think I will have to give that a try. Had kicked around the idea of just milling some out of aluminum but your way would be easier. The tail lights are just stickers. I did make the amber beacon on top of the ROPs a flasher but that is all as it didn't need any kind of controller. Would really be nice to have working lights but I don't know how.

[Zabco]

Bruder Piggyback Forklift Build part 4

In this post I'll start on the assembly of the mast lift system, specifically the lift motor and screw. The first step will be to disassemble the mast into it's two main components. There is a looped cable on both sides of the mast and you'll note that each has a clear plastic ball crimped to it and held in a square box on both sides. Using a very narrow screwdriver or similar tool stick the blade into the hole on the back side and carefully pry the balls outward.

https://i.postimg.cc/tThh5G7m/DSC-9182-0036.jpg (https://postimages.org/)

Then pressing out from the back side the tab shown in the next photo you can pull the upper mast from the lower mast.

https://i.postimg.cc/PJyYgbWW/DSC-9183-0036.jpg (https://postimages.org/)

And we have the two mast assemblies free to work on. It is not necessary to try and separate the lower mast from the base and I wouldn't advise trying.

https://i.postimg.cc/90mqY46r/Mast-Dissasembled-0237.jpg (https://postimages.org/)

This next photo shows some more of the parts from Thingiverse for this conversion with their associated file names. Most of these parts are for the mast assembly.

https://i.postimg.cc/vT0xqYyX/Print-Parts-4-0243a.jpg (https://postimages.org/)

In my build I did not use any of these parts. I have been building models for decades, long before there were 3D printers. And while I really love my printers I prefer to make some parts out of metal, especially if they will be moving or carrying loads. The thingiverse parts work as attested to by the photos and video the original creator posted on Facebook and If you wish to use them by all means do so. Their assembly will pretty much follow the same procedures I used, you'll just use more glue and fewer screws.
As an example, the motor mount from the thingiverse files to me looked kinda thin. Granted, as discussed earlier, you can't lift much weight without tipping the machine over, but the plastic part is glued to the mast and I've had problems in the past with some glues not sticking well to Bruder plastics.
This photo shows the printed motor mount on the right and the one I made from a piece of 3/4 x 1/2 x 1/16 in angle aluminum. The screw holes were spaced to match the mounting holes on the lift motor gearbox and a couple of ribs on the mast assembly.

https://i.postimg.cc/fRJmP9Jd/Lift-Mtr-Mnt-Compare-0234.jpg (https://postimages.org/)

I wanted to keep the motor/gearbox as low as possible so that the lift cylinder could be as long as possible. Thus I needed to cut away a portion of the very bottom of the lower mast. The red lines in this photo showed where I cut.

https://i.postimg.cc/Hx4yM0Pq/Mast-Lwr-Stock-0239a.jpg (https://postimages.org/)

And here is the result:

https://i.postimg.cc/FRQS1CGb/Mast-Lwr-Modified-0238.jpg (https://postimages.org/)

The holes for the screws used to attach the motor mount to the lower mast were marked and drilled out. I used #2 sheet metal screws. Note the holes are in line with ribs on the mounting surface to give the screws as much material to bite into as possible.

https://i.postimg.cc/0NSmk1G2/Lift-Mtr-Mnt-Holes-0235.jpg (https://postimages.org/)

Then a trial fitting of the lift motor.

https://i.postimg.cc/ncvhhVgW/Lift-Motor-Installed-0230.jpg (https://postimages.org/)

Note that I used round head screws. This was a mistake. I should have used flat head screws but did not have any at the time and didn't want to go and try to find some. The problem with these round head screws I soon found is that they stick out so far that they interfere with the bottom of the upper mast from being able to slide past. Instead of replacing the screws, what I did was to cut away a bit of the back side of the upper mast until it would clear the screw heads.

https://i.postimg.cc/8cmm1gSr/DSC-8776-0074a.jpg (https://postimages.org/)

This is a picture of the lower backside of the upper mast. The yellow dots represent the screw heads for the motor mount. The red lines are where I had to cut away plastic until the upper mast would slide past the screws. While this solution worked, it led to another problem later on. Should have gotten the flat head screws but too late now.

Speaking of the bottom of the upper mast, some more surgery is required here as well. Need to cut away a portion of the very bottom so it will slide past the motor/gearbox. Looking down from the top rear, this photo shows with the red line what needs to be cut away.

https://i.postimg.cc/MGn51Lyh/DSC-8773-0072.jpg (https://postimages.org/)

And the upper boom with the piece cut off. This cut also had the benefit of getting rid of the locking tab that prevents the mast sections from being easily pulled apart.

https://i.postimg.cc/BQJCmbT5/DSC-8775-0073.jpg (https://postimages.org/)

Time for the lift screw. The designer of these thingiverse parts used an M3.5 lead screw for his conversion. It came with a plastic nut that he cut down and glued into the 3D printed cylinder. Note from the earlier photo that the cylinder has larger ends to enable the lead screw nut to be inserted in one end and a set screw to be installed in a cross drilled hole to attach the cylinder to the gearbox shaft. Again, I was a little wary of the strength of the cylinder given it's thinness and wasn't sure how long the set screw would stay secure. I decided to go with a brass cylinder assembly.
I hunted all over the internet for a source of small diameter lead screws in the US. Absolutely no luck. Finally went to Ali Express. I hate that long wait for the slow boat from China. I needed a lead screw with a brass nut so I could solder it to the brass tube I would use to make the cylinder. I could not find a M3.5 screw with a brass nut so I ended up getting an M4 lead screw that came with a brass nut. The screw I ordered was 150mm long which is plenty for this application.

https://i.postimg.cc/bvS0ZtPP/DSC-8790-0083.jpg (https://postimages.org/)

Chucked the nut up in a lathe and turned it down to be a slip fit into a 1/4in diameter brass tube. I could have, and found later should have, gone with a smaller diameter tube but I wanted to make sure I could solder the nut in place and keep the solder out of the threads. No tap for these lead screws so would have been a real pain to clean out any solder.

https://i.postimg.cc/x1C3SZFc/DSC-8793-0086.jpg (https://postimages.org/)

I sized the length of the tube by measuring the distance from just above the gearbox mounting screws to the top of the lower mast. I wanted the cylinder to be as long as possible so that I could get the maximum amount of lift without having the screw come completely out the top of the cylinder. Soldered the turned down nut into one end of the brass tube. In the other end I soldered a 1/4in length of brass rod that was then center drilled 3mm to fit the gearbox shaft and cross drilled and tapped for a #6 set screw. Here is a photo of the screw end of the completed cylinder.

https://i.postimg.cc/Hs39Rmzq/DSC-8794-0087.jpg (https://postimages.org/)

Next I decided to make a cover to hide the gearbox and motor to make for a cleaner look to the front of the machine. So I designed and printed one up. It is just a snap fit over the motor so can be easily be removed if necessary.

https://i.postimg.cc/qMm2QLM0/DSC-8826-0111.jpg (https://postimages.org/)

Time to check the fit of everything built so far. Attach the motor/gearbox to the front of the lower mast. Attach the lift cylinder to the gearbox shaft. Insert the upper mast onto the lower mast. And, oops, I have a problem. The motor mount is wider that the clearance hole cut in the bottom of the upper mast. No problem. Take everything apart, clamp up the lift motor assembly in a vice and file the sides of the mount down.

https://i.postimg.cc/GtCjwhZC/DSC-8780-0075.jpg (https://postimages.org/)

Put everything back together (get used to doing this) and check fit. Success. This photo shows mast with upper section raised.

https://i.postimg.cc/4465vV9N/DSC-8781-0076.jpg (https://postimages.org/)

And with the upper mast section fully lowered.

https://i.postimg.cc/gJRKT6ts/DSC-8782-0077.jpg (https://postimages.org/)

That's all for this post. In the next I'll show what is probably the trickiest part of this entire project. Assembling and adjusting the limit switches.

[dremu]

Good idea, I think I will have to give that a try. Had kicked around the idea of just milling some out of aluminum but your way would be easier. The tail lights are just stickers. I did make the amber beacon on top of the ROPs a flasher but that is all as it didn't need any kind of controller. Would really be nice to have working lights but I don't know how.

Yeah, love me those beacons as they're so simple.

And M3.5? Who thought of that? Sheesh.

I bow to your successful use of the N20's. I've only recently looked at them as I've previously used the 9gs, but the gearing coupled with the even smaller size is attractive.

Wrt lighting, one word: Arduino. Yes, you gotta learn a bit of "programming", but there are a bazillion tutorials on the web so it's not a word to be afraid of. Also, they are just MADE for this sort of thing; they drive LED's almost directly (fine, you need a resistor), and can come in fairly tiny form factors. I don't know your TX setup well, but mine sends out all of its channels on essentially an RS232 serial bus, ie like those on a computer, so it's easy to make work with the Arduino. Then you just read the channels, and say something like

if (channel[1] < 1450) {turnonLED(left);} // left turn
else if (channel[1] > 1550) {turnonLED(right);} // right turn
else {turnoffLED(left); turnoffLED(right);}

total psuedocode, not exactly how it's written, but you get the idea. The deadband of 1450...1550 in the middle lets the stick float a little before doing the lights. If your stick is hyperaccurate you can turn it down to 1495...1505 or whatever (see below about making changes via pushing buttons! :) )

If instead it's auxiliary lights on a switch, you just do

if (channel[6] > 1750) {turnonLED(aux);} // switch on
else {turnoffLED(aux);} // switch off

Blinking is a bit more complicated, but you start simple and work your way up. The key thing in my mind is that once you get the 'dweeno and the LED's set up, the rest is done in software, so if you want to add new features or blink patterns or whatever, you don't have to swap out the board, just USB it to your computer and upload the new code.

I tend to use these guys

https://www.arduino.cc/en/pmwiki.php?n=Main/ArduinoBoardProMini

They're about 0.7" x 1.3" (err, 18x33mm), and the generic ones are a coupla bucks per, especially if you get a multipack. They'll run right off a 2S LiPo, or the RX BEC if you're using 3S+. They can drive servos directly, easy peasy, and like I said LED's just need one resistor, so the basic RC stuff is a breeze.

There are smaller boards if you're that tight for space, but you tend to lose functionality as they don't have room for connections for the fun stuff.

Anyway, I'll stop proselytizing now =)) but feel free to inquire if you're interested. (Also I think some of my build threads have more detail as they use one or multiple Arduinos.)

-- A

[Zabco]

Wrt lighting, one word: Arduino. Yes, you gotta learn a bit of "programming", but there are a bazillion tutorials on the web so it's not a word to be afraid of.

-- A

Actually I have played around with Arduinos and Raspberry Pis since the Arduino Duemilanove board came out. I just don't think that there is room inside the lift for even a nano sized board. The nano has a 30mA limit per pin so even with just 2 LEDs on a circuit you might need to also incorporate a switching transistor besides the resistors. I used a RasPi Zero as the basis for my portable message sign that I built a couple of years ago. I recently acquired some arduino nano clones that have packet radio capability that I am going to try to integrate into another project that I'll post up if it works out. I would really love to see some one do one of these piggyback conversions and be able to incorporate lighting, just not going to be me at this time.

[Zabco]

Bruder Piggyback Forklift Build part 5

I'll start this posting off by installing the lead screw. In the previous post there was a photo showing 5 of the parts that can be used for this conversion from Thingiverse. The originator of these parts did not incorporate any way to secure the lead screw to the mounting piece that goes on top of the upper mast assembly. Looking at the photos of his build he posted on Facebook he simply just glued the lead screw to the top of the mount with a blob of some kind of adhesive. This is the one thing about his build that I really did not like. I decided to make my lead screw mount out of 1/4" aluminum bar stock.

Photo shows the top of the upper mast, the 3D printed part from thingiverse and the aluminum bar stock I used to make my mount. I used my milling machine to make this part but I've made similar parts in the past with a fine tooth hacksaw, files and a little patience. I used the same dimensions as the 3D printed part except I did not add the boss in the top center. What I added was to cross drill through the center hole and tap for two set screws, one from each side. These would hold the lead screw in position and keep it from turning.

https://i.postimg.cc/j2mYbSpZ/DSC-8796-0089a.jpg (https://postimages.org/)

The hole you see in the top of the mast was sized to allow the 1/4" tubing being used for the lift cylinder to extend through to the bottom of the lead screw mount. The hole was located using the 3D printed part as a guide by holding it in position on the top of the mast and sliding a transfer punch through the center hole.

This photo shows the lead screw mount secured in place at the top of the upper mast.

https://i.postimg.cc/ZqSZn0CQ/DSC-8831-0115.jpg (https://postimages.org/)

Next is to determine the length of lead screw needed. To do this I put the upper mast back on the lower mast and placed the assembly back on the lower body. I blocked up the rear of the body to match the height of the original toy and set the forks to the same level.

https://i.postimg.cc/G2bc79RD/DSC-8812-0103.jpg (https://postimages.org/)

Then I ran the lead screw down through the top of the mount, down though the cylinder until if hit the top of the gear box shaft at the bottom of the cylinder. Unscrewed back about 1/2 turn and marked the lead screw at the top of the mount. This is where the excess screw needed to be cut off.

https://i.postimg.cc/d3xwVByR/DSC-8815-0106.jpg (https://postimages.org/)

After cutting the excess off I filed two flats on the end of the screw for the set screws in the top mount to bear against and keep the lead screw from turning.

BTW: one big benefit of having my parts assembled with screws as opposed to gluing them, it is relatively easy to remove the lift motor, cylinder and lead screw to check fits and make adjustments. I bet I had these parts in and out a couple of dozen times during the conversion.

Next comes the real fun, the limit switches.

The fourth photo of my last post shows some of the parts in the Thingiverse files. We need the part in the lower right called 'ups_tipper'. This part actually serves two purposes. The back side will hold the servo for tipping the mast forward and backwards. The front side serves as the mounting plate for the limit switches. Start by cutting some plastic away at the top of the bottom mast section. The red dashed lines in the photo below show where to cut.

https://i.postimg.cc/bYCzgzBG/DSC-8784-0079.jpg (https://postimages.org/)

And here is the lower mast with the plastic cut out.

https://i.postimg.cc/281CXPs0/DSC-8785-0080.jpg (https://postimages.org/)

The printed part fits in as shown. The curved portions of the part should fit on the curved sections of the mast which I guess are supposed to represent hydraulic cylinders.

https://i.postimg.cc/XYF4n97F/DSC-8786-0081.jpg (https://postimages.org/)

This is what the front of the lower mast looks like with the printed part in place.

https://i.postimg.cc/HxWg0K04/DSC-8789-0082.jpg (https://postimages.org/)

Fortunately for me I did not glue this part in place. I thought it might be a good idea to check the fit of the switches I was going to use and make sure they would fit between the mounting plate and the lift cylinder. They did not!!! I was using the same size/type switches that the originator of the parts files used. These are 2A mini snap switches and are about 5.8mm thick. After some head scratching the cause of the problem was obvious. The printed cylinder is much smaller in diameter than the 1/4" brass tubing I used to make my cylinder. If you use the printed cylinder and other parts and the same type of switch you probably won't have this problem, but check the fit before gluing anything in place.

How to fix. I wasn't going to scrap the brass cylinder. What I decided to do was redesign and print a new mounting plate. After a lot of careful measuring I determined I needed about 2mm more clearance between the mounting plate and the backside of the cylinder. I basically copied the original part but extended the mounting posts by 2mm. I also added a notch to the servo side to clear the servo wires as the micro servo I was going to use had it's cable exiting the body about half way down it's length instead of at the bottom like the mount was designed for.

I next found another problem. By moving the switches back 2mm their arms would no longer hit the parts of the upper mast assembly they needed to hit in order to operate. The fix for the top switch (which stops the lift motor as it lowers the mast) was to simply glue on a piece of styrene at the top back of the upper mast extending the contact point back to where it will hit the switch arm. It was left taller than needed and will be filed down to tune the stopping point later.

https://i.postimg.cc/3NR3h6dJ/DSC-8811-0102.jpg (https://postimages.org/)

The fix for the bottom switch (which stops the lift motor as it raises the mast) was a bit more complicated. First I glued in a square piece of styrene that went across the inside of the left upper mast frame. It sits right on top of the part I had to cut plastic from to clear the round head screws I used to mount the lift motor. NOTE: even if you use the 3D printed parts, if you use round head screws for mounting the motor you may have to do this same procedure for the lower switch. I also had to file away some the plastic I added at the front to clear the fork mount.

https://i.postimg.cc/4dwXrZ4S/DSC-8819-0107.jpg (https://postimages.org/)

I then had to modify the arm on the switch as it's position would be too low to hit the plastic trip bar I just added. I cut and shaped an extension to solder onto the end of the switch arm. And truthfully I just eyeballed it's length and shape knowing that I would have to reshape and adjust it's position when fine tuning.

Finally, just to make sure the switches would fit I sanded both sides of each switch to make them just a little thinner. Have to be careful that you don't take too much off or the latches that hold the switches together will fail.

This photo shows both switches prior to being installed.

https://i.postimg.cc/59RVvsXL/DSC-8806-0097.jpg (https://postimages.org/)

[Zabco]

Bruder Piggyback Forklift Build part 5b
(Had to split this post because of posting size limitations)

I glued both switches to the mounting plate in positions shown. The switch on the left will be on the bottom when installed in the mast. When cured I soldered diodes and a jumper wire in place. I used 1N4003 diodes which are rated for 1A which is plenty for these little N20 motors. Then tested the switches to make sure the circuit worked properly.

https://i.postimg.cc/BvTSBHrs/DSC-8808-0099.jpg (https://postimages.org/)

At this point I was now ready to glue the switch mounting plate into position at the top of the lower mast. I used a 2 part epoxy for this. While the epoxy was curing I wired up the lift motor with extra long leads that could be trimmed as needed later. The red wire will go up to the limit switches and the black will go to the motor ESC in the body of the lift.

https://i.postimg.cc/cCrG2nbv/DSC-8804-0096.jpg (https://postimages.org/)

Next was to run a longer than needed wire into the bottom backside of the lower mast and run it up the right side of the mast to the switches. The lift motor was reinstalled and it's red wire was also run up the right side to the switches. I cut a small notch in the side of the mast even with both switch's lugs and bent one wire over to each switch and soldered into place as shown.

https://i.postimg.cc/fTPRzw74/DSC-8809-0100.jpg (https://postimages.org/)

This photo shows the lower mast assembly with the lift motor and completed limit switch mount and wiring in place. Big sigh of relief.

https://i.postimg.cc/KYScTJsJ/DSC-8810-0101.jpg (https://postimages.org/)

The only thing left was to fine tune the activation of the limit switches. Put the upper mast assembly back into position in the lower mast and installed the lift cylinder. Connected a temporary power supply to the wires from the lift motor and started running the mast up and down. Adjusting the top switch was fairly easy. After lowering the mast till it came to a stop, check the position and if was still a little high just sand a little bit more off the bottom of the trip plate on the top of the upper mast. It ended up looking like this.

https://i.postimg.cc/Gmsh9Zz4/DSC-8820-0108.jpg (https://postimages.org/)

Adjusting the action of the lower switch was a bit trickier. I started with the end of the extension I added to the switch arm bent a bit lower than where I knew it needed to be. Raise the upper mast and see where it would stop. Then carefully reach in with a set of needle nose pliers and/or needle file and carefully make a small adjustment to the bend or length of the hook and try again. Took some time but eventually got there. Really big sigh of relief.

https://i.postimg.cc/VNWwC1tk/DSC-9185-0036.jpg (https://postimages.org/)

I will admit to another error I made. If you look closely at the last photo and the one showing the limit switches mounted at the top of the mast above you might notice that the polarity band on the diodes have changed position. Apparently because I used two red wires up the mast to the switches I didn't pay enough attention to which was which and I got them backwards. The wire to the lower switch was now too short to reach the upper switch so I couldn't just swap them so I had to swap the diodes end for end. Since they were already mounted that meant the swap had to be done with them inside the mast. Not much room for error with a hot soldering iron. Pay attention!

Here is a photo of the completed mast lift assembly from the front;

https://i.postimg.cc/Pr0dGShT/DSC-8821-0109.jpg (https://postimages.org/)

and the back.

https://i.postimg.cc/hjCq2rpF/DSC-8822-0110.jpg (https://postimages.org/)

That's all for now. In the next part I'll show how the mast tilt assembly goes together.

[dremu]

Actually I have played around with Arduinos and Raspberry Pis since the Arduino Duemilanove board came out. I just don't think that there is room inside the lift for even a nano sized board. The nano has a 30mA limit per pin so even with just 2 LEDs on a circuit you might need to also incorporate a switching transistor besides the resistors. I used a RasPi Zero as the basis for my portable message sign that I built a couple of years ago. I recently acquired some arduino nano clones that have packet radio capability that I am going to try to integrate into another project that I'll post up if it works out. I would really love to see some one do one of these piggyback conversions and be able to incorporate lighting, just not going to be me at this time.

Apologies, one of these days I'll learn to check for previous experience before I go frothing off at the mouth. Might be a little Arduino happy :|

Wrt the current limit, though, I just drive one LED per pin, and haven't had any trouble at 20mA. Cuts down on component count, but as you say, room is still at a premium. I know Adafruit has their Trinket line that are tiny, or maybe you could just use a bare '328 chip, but then you need a voltage regulator and at least a connection to program it ... ugh.

Anyway, I'll stop going off topic, and just say wow. I'm particularly interested in the limit switches as I wanna do something similar for a telescoping column for another project and I have a box of those very switches awaiting the time and work.

-- A

[Zabco]

Apologies, one of these days I'll learn to check for previous experience before I go frothing off at the mouth. Might be a little Arduino happy :|

Wrt the current limit, though, I just drive one LED per pin, and haven't had any trouble at 20mA. Cuts down on component count, but as you say, room is still at a premium. I know Adafruit has their Trinket line that are tiny, or maybe you could just use a bare '328 chip, but then you need a voltage regulator and at least a connection to program it ... ugh.

Anyway, I'll stop going off topic, and just say wow. I'm particularly interested in the limit switches as I wanna do something similar for a telescoping column for another project and I have a box of those very switches awaiting the time and work.

-- A

No problem with me. Thinking back I don't think I've posted a build that uses an arduino or other microprocessor so you wouldn't have found anything anyway. And your info might be of use to others who are not familiar with arduinos.

I love Adafruit, they are a great company to deal with. I use a lot of their components. I really like that they are in the US and manufacture a lot of what they sell in house.

With the limit switches you just have to pay attention to polarity of diodes, as apparently I did not as noted in last post. For those not familiar with these limit circuits I should have mentioned also that these types of switches have both a Normal Open (NO) and a Normal Closed (NC) circuit which is usually shown on the side of the switch right above the pins. There are usually 3 pins or lugs for wiring, one is a common, one for the NO circuit and one for the NC circuit. For limiting motion of motor drives we want to use the NC circuit. On the switches I used that is the outside two pins. I cut away the third pin to avoid confusion later and a small diode will fit nicely into the space left. There are numerous utube videos detailing how to make these circuits and how they work.

[Zabco]

Bruder Piggyback Forklift Build part 6

Ok, that is the worst of the actual mechanical part of the build. In this part I'll show how I installed the mast tilting capability. It's pretty simple and straight forward.

The first step was to take a knife and shave off the nub that engages the detents at the base of the mast that are used to hold the mast in it's manually tilted positions. There is one on each side. We want the mast to freely tilt back and forth.

https://i.postimg.cc/fbm8jv55/DSC-8834-0118a.jpg (https://postimg.cc/3yrj3msD)

The tilt mechanism uses a standard 9gr micro servo. We already installed the mounting bracket as it is the backside of the limit switch mounting plate. Install the servo and train the cable down the back right side of the mast. The mounting plate from the Thingiverse files is designed for a servo that has it's cable coming out at the bottom of the servo. If you servo is like mine with the cable coming out the side just cut a slot in the mount in the appropriate place.

https://i.postimg.cc/cHc8dK4d/DSC-8835-0119.jpg (https://postimages.org/)

I like to use ball connectors when making up linkages as they eliminate almost all slop. I had some very small connectors that were salvaged from an old helicopter that I used here. Larger ball connectors, clevis links or even Z-bends could be used. Just try to keep the linkage as tight as possible. I mounted the bottom connector at the rear of the mast base down near the bottom as shown below. Simply drilled appropriate size hole and screwed the ball in place.

https://i.postimg.cc/0y6m72ZC/DSC-8849-0131.jpg (https://postimages.org/)

It takes very little servo arm movement to make the mast tilt back and forth. So I cut the servo arm back to one hole and installed a ball connector to the arm. Installed the arm on the servo pointing straight back after making sure the servo was centered. Measured the distance between the two connectors with the mast standing straight up and made up the appropriate length connecting rod.

https://i.postimg.cc/hGTd3ykz/DSC-8850-0132.jpg (https://postimages.org/)

Here's an overall view of the completed linkage.

https://i.postimg.cc/zG9h7ZcY/DSC-8851-0133.jpg (https://postimages.org/)

The final step was to make a small clip and screw it to the mast base to hold the servo cable and lift motor leads in place.

https://i.postimg.cc/Y97WcN7X/DSC-8880-0156.jpg (https://postimages.org/)

That's it! I mentioned above that it takes very little movement of the servo arm to tilt the mast back and forth and in truth the design of the mast does not allow for a lot of motion. So to prevent over stressing the tilt mechanism at it's limits I have my transmitter end points set to plus and minus 30 percent on this channel.

Next post I think I'll do some body work.

[Zabco]

Bruder Piggyback Forklift Build part 7

Taking a break in this post from mechanical modifications. Instead I'm going to do some body work. One of the big problems with converting this Bruder forklift to RC is of course the size. There just isn't much room in this thing for all the electronics that need to go in and not have parts sticking out all over the place. With the exception of the tilt servo I think I've been pretty successful at this up to now. One of the biggest components that needs a home is the battery. They are big and bulky. The only place in this model that a battery can realistically fit is inside the right side of the body where, on a real forklift like this, the engine would sit. Another consideration is how to charge and/or change the battery. You could, I suppose, just take the thing apart or run a charging plug to the outside somewhere. I didn't like any of those options. What is needed is a removable hatch. So happens the model has a hatch over this engine area molded in to it already.

https://i.postimg.cc/sgYWdbkR/DSC-8759-0058.jpg (https://postimages.org/)

If we cut this molded hatch out it would make a pretty good sized opening that a small battery pack could be inserted. So that is what I decided to do. I wanted to minimize damage to areas around the hatch and because of all the curves in this piece I decided to use the good ole fashion method of sawing the part out with thread. For those not familiar with this technique you get a spool of just about any kind of thread, the thinner the better. Pull off a length, keep it pulled tight between your hands and just start moving the thread back and forth in a sawing motion. The friction of the thread against the plastic will cut right through. It helps to slightly pull the thread against the plastic in the direction you want to cut. Go slow, especially around the corners and you'll be surprised at how quickly plastic can be cut. With a little practice it can be quite accurate.

https://i.postimg.cc/bvL2dkYC/DSC-8761-0060.jpg (https://postimages.org/)

If you look back at the first photo you might think that the place to start sawing would be on the left side of the hatch where there is no body. I don't recommend this. The thread method works well but can wander just a bit when first starting a cut and I wanted to leave the corner of the body as sharp as possible. If you look back at the last photo and look carefully you'll see a very small hole I drilled near the center of the top line of the hatch. This is where I inserted the thread. I then cut back to the left and down to free that side of the hatch leaving a nice point on the end of the body. Then came back and cut out going to the right, down and finally back to the left on the bottom.. I cut right through both of the simulated hinges as I figured I was just going to sand them off anyway.

Here is the hatch cut completely out.

https://i.postimg.cc/PNGC0MKx/DSC-8763-0062.jpg (https://postimages.org/)

Needed some kind of support to hold a removable hatch in place. So I took some pieces of small square styrene and glued then in around the perimeter of the hole I just cut leaving about half of the plastic exposed.

https://i.postimg.cc/NMM2XF5g/DSC-8764-0063.jpg (https://postimages.org/)

Now I need a new hatch to fill the hole. One of the Thingiverse parts is a new cover for this area. However I thought it looked to squarish and it didn't match the curves of the model so decided not to use it. I could have reused the part I cut out but would have had to spend some time gluing plastic to the edges of make up for the gap left by the thread. Even as thin as the thread is, it leaves a noticeable kerf. I decided to design and print my own. With some very careful measuring using calipers, a digital angle finder and radius gauges I came up with a design. Below is a photo with the Thingiverse cover on the right and my cover on the left.

https://i.postimg.cc/tg9xX2bn/DSC-8769-0068.jpg (https://postimages.org/)

After a little sanding to tweak the fit here is the new cover sitting in place.

https://i.postimg.cc/L4JNK6NK/DSC-8770-0069.jpg (https://postimages.org/)

To keep the cover in place I thought about making hinges to replace the molded ones that got cut and sanded off. But because of the size needed to look right I decided that was too much work. Instead I opted to just install a couple of lugs that would fit in gaps under the top portion of the opening and use a small super magnet on the bottom to 'latch' the cover. The magnet needs something to grab so I cut a small piece of tin and glued it into a small recess cut in the bottom back side of the cover.
Here is the opening for the cover with the notches cut out of the previously installed plastic supports. There is a big piece missing on the upper left because there is just not a large enough under-hang here to glue the styrene to and I couldn't get it to stay in place there. The rest is more than adequate for support. To hold the magnet in place I glued another short piece of sytrene onto the inside of the wall placed to hold the magnet at the right height and then CAd the magnet in place.

https://i.postimg.cc/d3Z7Wf2p/DSC-9111-0182.jpg (https://postimages.org/)

And here is the underside of the cover so you can see the lugs and tin 'magnet catch'.

https://i.postimg.cc/qBWQkV5t/DSC-9109-0180.jpg (https://postimages.org/)

The last step was to add a handle to the cover to make it easier to open. I just bent a piece of 1/16" Plastruct plastic coated wire to a shape I liked, drilled matching holes in the cover, inserted the wire ends and glued in place with PlasicWeld.

https://i.postimg.cc/8zQvYTnH/DSC-9110-0181.jpg (https://postimages.org/)

Here is a photo of the completed battery hatch cover. Of course like any 3D printed part it still needs some final filling and sanding before it will be ready for paint.

https://i.postimg.cc/j5Fw4T7y/DSC-9112-0183.jpg (https://postimages.org/)

Now that the battery hatch is complete I could take some internal measurements and get an idea of exactly how big of a battery pack I could fit in. Keep in mind though that you can't use the entire space. Some room will be needed for the mechanism to move the lift mast assembly forward and backward. Which is what I will cover in the next post.

[Zabco]

Bruder Piggyback Forklift Build part 8

The last mechanical assembly that needs to be installed is the servo and linkage to move the lift mast assembly in and out. The original poster of the Thingiverse conversion parts used what some refer to as a wing or aileron servo. They are designed to fit in narrow places like wings. These servos are narrower than conventional servos and have their mounting flanges sit flush and parallel to the back of the servo instead of being perpendicular to the back. He designed his servo mount accordingly. I didn't have any of these servos on hand so decided to see if I couldn't fit a standard mini servo into the same space. After some measuring I determined that I could. But how to mount it? I could make a mount similar to the Thingiverse part but with a top screw hole for one end and a second mount to attach somehow to the curved wheel well housing wall on the other end. That would be tricky and could obstruct the ability to run wires through that area later on. After studying the shape of the servo I wondered if it wouldn't be possible to make a mount that only used one screw for one end of the servo and then wrap around the round portion of the servo and keep it from moving side to side under load. After making up a couple of trial mounts I came up with the design I finally used and it seems to work well.

The photo below shows the servo mount from Thingiverse on the right and my mount on the left.

https://i.postimg.cc/VLBy33yX/DSC-8860-0141.jpg (https://postimages.org/)

The mount fits into the lower body as shown below.

https://i.postimg.cc/J7ZSk9zS/DSC-8862-0143.jpg (https://postimages.org/)

I drilled a couple of holes up through the bottom of the body and into the mount to secure it with screws. NOTE: The mount needs to be turned 180 degrees from shown for proper orientation, I wasn't paying attention when I took this photo. Also the photo shows round head screws again. Don't use them.

https://i.postimg.cc/KY1HvWWq/DSC-8864-0145.jpg (https://postimages.org/)

You must use flat head screws here or the lift mast assembly will not be able to slide past! Yea, after all this time I finally broke down and bought some flat head screws. ****, I bought hundreds so I won't have this problem ever again.

https://i.postimg.cc/qMrSXjtq/DSC-8874-0150a.jpg (https://postimages.org/)

The next photo shows how the servo fits in the mount. When I first installed the servo I used a standard flanged head mounting screw that came with the servo. I found though that the flange would not clear the inside of the top body section when I tried to lower it in place.

https://i.postimg.cc/t4Cc8JNH/DSC-8869-0149.jpg (https://postimages.org/)

If I removed the flange or used a smaller screw I did not think the servo would be held securely enough as the mounting hole on the servo is larger than the screw so that a rubber vibration isolater can be used. Don't need the isolator in this case and I wanted the servo mounted solidly. So I cut off a short length of plastic rod and center drilled it to make a bushing to take up the excess space.

https://i.postimg.cc/3xSqhht0/DSC-8863-0144.jpg (https://postimages.org/)

I then cut and drilled a piece of brass bar stock to use as a clamp across the entire width of the servo's mounting flange. This photo shows the final mounting. You can see that I also started to remove some of the internal plastic.

https://i.postimg.cc/L4PFVJNC/DSC-8876-0152a.jpg (https://postimages.org/)

I again used ball connectors to make up the linkage between the servo and lift mast base. I used Tamiya 4mm balls and connectors just like the ones used in their truck kits. You can buy these direct from Tamiya but be aware that they refer to them as 'adjusters'. I mounted one ball on the end of the longest servo arm that came with the servo and oriented it pointing down as installed on the servo.

The ball for the lift mast base was mounted as shown. Exact placement is not critical. There isn't room on the underside to install a nut so the hole I drilled for the ball was undersized and then I forced the threads to cut their way through the plastic as I installed the ball.

https://i.postimg.cc/5NMdKfrx/DSC-8882-0158.jpg (https://postimages.org/)

Because there was not a nut on the backside of the ball connector I was a bit concerned about it eventually working itself loose. So I mixed up a small amount of 2 part epoxy and poured it into the cavity where the screw thread was and embedded it.

https://i.postimg.cc/13mxPJP2/DSC-8884-0160.jpg (https://postimages.org/)

And here is the linkage to connect the two balls together. Note that I cut the threaded ends of the connectors back a bit. I did this to make it a bit easier to make length adjustments if needed without having a lot of friction to fight.

https://i.postimg.cc/kG3ZHyfj/DSC-8885-0161.jpg (https://postimages.org/)

And that's pretty much it. In this photo you can see how the servo fits inside the body. There is still quite a bit of room left for a battery pack. In this photo the servo is shown in its neutral position.

https://i.postimg.cc/1zdbGS61/DSC-8886-0162.jpg (https://postimages.org/)

Like the steering servo, I needed more servo arm movement than the standard 90 degree left/right. One option would be to install a longer servo arm but that might start causing clearance problems. Or I could install resistors in the servo to increase it's range. Maybe a little easier to do in a mini servo as opposed to a micro servo but not what I wanted to do. Again I was able to open up the set points on my transmitter for this channel to 150%. That gave me enough linkage movement to be satisfactory. This photo shows the mast in it's full forward position.

https://i.postimg.cc/jSZpjPS5/DSC-8887-0163.jpg (https://postimages.org/)

The mast assembly could be moved forward a bit more but as long as the back side of the forks would clear the front of the body I was satisfied. You can see that the mast itself is now in front of the center of the front wheels. Those wheels are the fulcrum for a lever and the further ahead the mast gets the easier it becomes to tip the forklift over. This last photo shows the mast fully retracted.

https://i.postimg.cc/pdrg5rmB/DSC-8888-0164.jpg (https://postimages.org/)

Again the mast assembly has room to move back a bit more. But some room is needed at the back of the mast base to allow the tilt servo cable and lift motor wires room to move. I may, after more operational experience, shorten up the link rod between the servo and the base plate. This would shift the entire lift mast assembly backwards. I have more front extension then really needed and it would move the mast further behind the front wheels increasing the amount of weight that could be lifted without tipping. We'll see.

That is all the mechanical adaptations that need to be made to make this model operational. In the next post I will address two other small items before we get into how to stuff 10 pounds of electronics into a 5 pound sack.

[Zabco]

Bruder Piggyback Forklift Build part 9

A couple of things to take care of before tackling the electronics. First, if you look back at the last few photos in the last post you see the open area in the body where the battery pack needs to go. You also see that there is the servo and linkage that moves the lift mast assembly in and out. We don't want the battery to hit or obstruct this linkage. So some kind of barrier needs to be made and installed to prevent this. I choose again to use brass but plastic or even wood could be used here as well. I measured the height from the inside bottom of the lower body to the top of the nut holding the ball connector on the servo arm and added 1mm. I just dug out some scrap square tubing and flat plate from my scrap box, cut to size and soldered up the parts as shown below.

https://i.postimg.cc/VsHWWcYD/DSC-9100-0171.jpg (https://postimages.org/)

The piece fits into the lower body as shown. The 'feet' on the bottom were sized to fit between the outside wall and a rib in the bottom.

https://i.postimg.cc/dtkmWS3v/DSC-9101-0172.jpg (https://postimages.org/)

Here's another view from a different angle so you can see a little better how the feet fit in. They were drilled for #2 screws and matching holes drilled in the bottom of body.

https://i.postimg.cc/WzKmN09Q/DSC-9102-0173.jpg (https://postimages.org/)

And here's a view of the bottom showing the mounting screws. Yep, flat head screws now, I finally learned although it doesn't really matter here as there is nothing that needs to move past these screws.

https://i.postimg.cc/hPk8NbQm/DSC-9103-0174.jpg (https://postimages.org/)

I actually did this part of the build early on which you might be able to tell from the photos. I did this so I could get a better ideal of just how big a battery pack I would be able to fit in. I had originally planned on using a 3S lipo. However the quality of the small ESCs that would work on 3S I discovered are horrible. They either have no real low voltage range to them or they blow out after a few seconds. They all come from China and they must all be made by the same company as it doesn't matter who you get them from they all look alike. I finally decided to try 2S battery and ESCs. This worked much better. I found some ESCs that claimed to be a new design and had a big capacitor hanging off one end. So far they have worked and held up well. The battery I finally settled on is made by a company called SPC Maker. It is 2S and rated 500mAh. It is primarily marketed to the racing drone group. It measures approximately 50x25x13mm and fit in the available space very nicely. And while it looks awfully tiny compared to the size of the batteries we normally use in our trucks and construction equipment I find that I can get a good solid hour of continuous operation out of it, which is plenty for me.

The last thing to be addressed before assembling all the RC electronics is the warning light on top of the ROPs. I didn't put any other working lights on my model but I did want that light to flash. This is a real simple conversion. I used a LED that had it's flashing circuit already built it. These are available from a number of sources, mine came from Eflite. It also included the necessary over-current protection resistor already installed. Photo below shows the light fixture and the LED.

https://i.postimg.cc/bvHRxDJt/DSC-8797-0090.jpg (https://postimages.org/)

I cut the socket fitting on the end of the wire off so I could add additional wire to the LED. Also if I had left it on I would have had to cut a much larger hole in the body to pass it through to the inside.

To remove the lens, just grab it and twist while pulling up. Mine came right off. Drill a 3mm hole right through the middle of the circle as shown.

https://i.postimg.cc/NMskps9P/DSC-8798-0091.jpg (https://postimages.org/)

There is a lug in the center of the lens that needs to be cut back some so it will sit down on top of the LED. Don't remove it completely as it will act as a light pipe make the lens appear brighter when the LED is lit.

https://i.postimg.cc/BbtcfmCT/DSC-8799-0092.jpg (https://postimages.org/)

I glued the LED into it's mounting hole from the bottom using CA. After it cured I then bent the wire to follow the inside of the ROPs cage and CAd it in place.

https://i.postimg.cc/76KMRFSP/DSC-8800-0093.jpg (https://postimages.org/)

Then the lens was glued back in place over the LED. To prevent possible fogging of the lens from CA I used a watch crystal cement.

The last step was to hold the ROPs in postion on the upper body and mark the location of the notch for the wires from the LED to enter the body.

https://i.postimg.cc/SKprY7y4/DSC-8801-0094.jpg (https://postimages.org/)

I crimped a couple of female connector pins to the ends of the LED wires. When installed these will just plug onto the positive and negative pins of the battery port on the receiver. When the receiver is powered up from the BEC of one of the ESCs it will also turn on the flashing LED.

At this time all the modifications are pretty much complete. I had tested each individual servo and motor system as it was installed. Now everything was hooked up and run though it's paces. I was very relieved to find that everything worked as it should. The model was stripped back down and sent to paint. I won't bother with showing any of that, painting is painting. Next post I'll start in on the 3d version of Tetris and figure out how to cram everything into the available space.

[frizzen]

That fork is really coming out awesome!!! I can't wait to see some videos in action, or see what kind of cargo you come up with!

If you want an LED to fill out a light better, fill the lens area with clear Hotglue, and assemble it while still hot. It evens out the light instead of being a focused point.

[Zabco]

That fork is really coming out awesome!!! I can't wait to see some videos in action, or see what kind of cargo you come up with!

If you want an LED to fill out a light better, fill the lens area with clear Hotglue, and assemble it while still hot. It evens out the light instead of being a focused point.

Good hint on the light, I'll have to remember for future use. As to video I don't know. I'm not that good at shooting video although I have done a few in the past. My real issue I guess is that I just hate U-tube anymore. Does anyone know of another easy to use and FREE video hosting site that works with this forum?

[Zabco]

Bruder Piggyback Forklift Build part 10

I'm going to split the installation of all the electronics into two parts. In this post I'll show all the components I used and some modifications. In the next I'll go over the actual installation..

At the end of the last post I mentioned that I hooked everything up and tested to make sure that after all the putting together and taking apart that it would all work properly. This photo shows everything laid out on a table and temporarily wired up as I tested.

https://i.postimg.cc/PqLCFFnm/DSC-9089-0165.jpg (https://postimages.org/)

Man, what a mess of spaghetti. In this photo you see the following parts: 1 battery pack, 2 ESCs, 1 6-channel receiver, 4 JST connectors, and next to the battery pack a pair of 3 terminal WAGO connectors. Will it all fit?

This is the battery I ultimately ended up using. While 500mAh doesn't sound like much capacity I have found in use that I can easily get a good solid hour of continuous run time out of it. And it fits easily into the space available. I purchased this particular battery from https://www.buddyrc.com They are an online only RC hobby store located in Columbus, OH. They primarily deal with the airplane/drone crowd but what hobby store doesn't. BTW, if you are looking for a RadioMaster transmitter they are dealers and also carry a wide array of spare parts.

https://i.postimg.cc/VvP0t9TX/DSC-9190-0038.jpg (https://postimages.org/)

This is the receiver I used in this build. It is a 6-channel DSM compatible unit so it will work with almost any Spektrum radio as well as Open TX radios such as the RadioMaster. This receiver is the smallest 6-channel one that I know of that will take standard servo connectors. The only ones smaller use soldered connections instead of plugs. These receivers also have the advantage of being relatively inexpensive. This one is a bare bones model by which I mean it doesn't have telemetering or a diverity or duplex antenna. I purchased this from BuddyRC also. Be aware if you shop for one of these they come in two basic versions. The one shown is the 'top' connected version. They also make it in an 'end' connected version which is going to be about 1/4" longer and you would also need extra room at the end for the plugs.

https://i.postimg.cc/JzYyxCvr/DSC-9188-0036.jpg (https://postimages.org/)

This next photo shows one of the ESCs I ended up using. These are 2S, 10A rated units. They have a 1A BEC and no braking. I originally wanted to go with 3S ESCs but couldn't find any that worked properly or that didn't let the magic smoke out after a few seconds. I really wish there was a source of US made ESCs. These were obtained on Ebay. They are all made in China so I don't think it really matters much which vendor you pick, I'd just look for one who states they ship from within the US. On the right side you can see a large capacitor extending out from the circuit board. This is apparently a new design, and so far, mine have worked well.

https://i.postimg.cc/rFJRdr9t/DSC-9189-0037.jpg (https://postimages.org/)

I made a few modifications to these ESCs. They came with a switch attached to wire leads to turn the ESC on and off. Since I was going to use a master switch I didn't need the attached switches. And I especially didn't need two switches.

To remove the switches I had to remove the plastic heat shrink that had been put on by the factory. Just use a sharp knife and pare down along one edge of the circuit board and peel off.

https://i.postimg.cc/QMRFLkjv/DSC-9120-0189.jpg (https://postimages.org/)

Then using a small soldering iron I heated up each blob of solder on the circuit board at each switch wire location on the lower right as shown. When each blob melts just pull the wire free. Don't remove the little blobs of solder.

https://i.postimg.cc/WbjJbn0v/DSC-9124-0191.jpg (https://postimages.org/)

Without the switch there is no way to turn the ESC on. Simple fix, just solder a small jumper across the two pads where the switch wires used to be. I just used a small piece of wire snipped from a resistor. The blobs of solder left behind from removing the switch wires should be enough.

https://i.postimg.cc/DwwJ1wCp/DSC-9126-0192.jpg (https://postimages.org/)

These ESCs are going to be mounted in a plastic body and all the wires on and around them will be insulated. But I still felt it wouldn't hurt any to re-insulate the boards. You could put heat shrink back on like they had originally but I decided to wrap them in Kapton tape. Kapton tape is very thin, very strong and has a very high dielectric or insulting rating. It's also not cheap. But I had a lot left lying around from my early 3D printing days when we used to put Kapton on the build platforms as a surface for the print to stick to. I primarily used it because it was a lot thinner than the heat shrink and I wanted all the spare room I could get.

https://i.postimg.cc/ZY6dSgBH/DSC-9130-0194.jpg (https://postimages.org/)

Since I had two ESCs that were going to be connected to the same receiver the last modification was to remove the red + wire from one of the servos so the receiver would only get power from one ESC.

So, next post I'll finally get to what most of you have been wanting to see. How I put it all the electronics inside the body of the fork lift.

[Zabco]

Bruder Piggyback Forklift Build part 11


OK, time to finish this up. Will everything fit inside. Of course, didn't you see my first post? There was some trial and error involved in deciding where to put the components but it actually was easier than I was afraid it would be when I started this conversion. There were a few snags and I'll point them out so you can avoid them.

The first step was to lay in a length of two conductor cable for the battery power supply as shown. It has a JST connector on one end and is longer than anticipated and will be cut to final length later. The red wire will go to the master switch under the operators seat and the black wire will actually get pulled back about to the center of the wheel housing for the negative return to the battery.

https://i.postimg.cc/RZ9cbXyD/DSC-9139-0199.jpg (https://postimages.org/)


The first component I mounted was the ESC for the drive motor. I simply hot glued the ESC to the back right side of the rear wheel housing as shown below. The large capacitor on top was just pushed over so it laid on top of the wheel housing.

https://i.postimg.cc/9MSd8VHd/DSC-9141-0200.jpg (https://postimages.org/)

So logically the second ESC for the lift motor should go on the other side of the wheel housing. So that's where I mounted it and again bent the capacitor over to lay on the wheel housing.

https://i.postimg.cc/TPdJhCcD/DSC-9142-0201.jpg (https://postimages.org/)

Using a piece of servo tape I mounted the receiver in the position shown. I placed the terminals for the servos on top so they would be easy to get to and figured that would give me room underneath to coil up excess servo lead. I bent the antenna wire to run along the side of the left wheel arm and taped it in position.

https://i.postimg.cc/hvd9NwKH/DSC-9144-0203.jpg (https://postimages.org/)

SNAG #1 - If you have been following this build and seen the 3D printed parts I've used from Thingiverse, have you wondered why the steering servo mount is straight instead of curved on the left side? It' because part of the top body section hangs down over the left side of the wheel housing in this area and there isn't enough clearance for the printed part. I tried assembling the top and bottom body sections together at this time to check fits and clearances and found that the capacitor on the lift motor ESC would not fit. If fact none of the wires sticking up from the ESC would fit. I think I got so used to just working on the lower body section that I forgot about this clearance issue. So after some study I removed the ESC and remounted it to the position shown below. I also mounted it lower so the wires wouldn't get in a bind with the top part of the model and bent the capacitor leads down over the front of the circuit board.

https://i.postimg.cc/T3qcRZnx/DSC-9145-0204.jpg (https://postimages.org/)

Next I mounted the master switch into the hole made previously in the top body section. In this photo I had placed the top body back into position to check clearance from the back of the switch to the receiver. Good reason for removing the drivers seat.

https://i.postimg.cc/DZmQP0Hf/DSC-9146-0205.jpg (https://postimages.org/)

I wanted to be able to completely separate the top body from the bottom for maintenance and repair work if ever needed. So I installed a XT30 connector as you see. I used this connector because it was the smallest two conductor connector like this I had on hand. The JST connectors are longer when assembled and I though they might get in the way. While the XT30 works I now wish I had taken the time to find something smaller. This doesn't need to be a polarized connector either. The switch is just in series with the positive battery lead. You can also see the second red wire added to go from the switch back to about the center of the wheel housing.

https://i.postimg.cc/h4zbJJVp/DSC-9148-0207.jpg (https://postimages.org/)

I had wanted to use the WAGO connectors to make the power connections. I really like those things but they were just a little too big to fit in the space between the front of the wheel housing and the front wall of the lift. I could have maybe put them at the bottom backside of the lift but would have then had to splice extra wire to the ESCs. Didn't feel like doing that much extra work. So I simply twisted the ends of the black wires and red wires together and soldered them. Then insulated the ends with a piece of heat shrink and a little tape. These wires are a little stiff so I held them in place with a couple dabs of hot glue.

https://i.postimg.cc/59h58x31/DSC-9149-0208a.jpg (https://postimages.org/)

Reinstalled the mast platform retraction servo.

https://i.postimg.cc/Ls8jmhHk/DSC-9150-0209.jpg (https://postimages.org/)

Followed by the battery platform. I covered the edges of the platform with a couple of layers to electrical tape to protect the wires from possible cutting.

https://i.postimg.cc/3wfmN7Rs/DSC-9151-0210.jpg (https://postimages.org/)

Next was to cut to length and splice the power leads from the drive motor to it's ESC. Solder and heat shrink tube to insulate.

https://i.postimg.cc/3J2XBPSG/DSC-9152-0211.jpg (https://postimages.org/)

I then wrapped narrow pieces of tape around the tilt servo leads and lift motor wires on the mast assembly to bundle them together. Place the mast assembly back into place on the lower body and connect the servo linkage.

https://i.postimg.cc/63DZV0Cz/DSC-9153-0212.jpg (https://postimages.org/)

Then the lift motor leads and and ESC leads were trimmed to length, spliced and heat shrink.

https://i.postimg.cc/MpDyk18K/DSC-9154-0213.jpg (https://postimages.org/)

Next is to run the servo and ESC control cables to the receiver. I won't show all of these being run. I ran the cables from the drive ESC steering servo and mast retraction servo across the top of the wheel housing to the receiver. The lift motor ESC and tilt servo cables were run across on the bottom of the body to the receiver. Each cable needed to be shortened to some degree so I wouldn't have a huge mass of wires under the receiver. So I ran one cable at a time starting with which ever cable I had assigned to channel 6 on the receiver. And then channel 5 and so on. I'm not using channel 2 so it's open as well as the battery port since power is coming from the drive motor ESC.

https://i.postimg.cc/SNb8JgSx/DSC-9159-0218.jpg (https://postimages.org/)

OK, as usual the web site is telling me I talk to much. Have to break this post here and will continue in the next.

[Zabco]

Bruder Piggyback Forklift Build Part 11b

(continued from previous post)

Ran the leads of the warning light on the ROPs through the notch cut earlier in the top part of the body and reinstall the ROPs.

https://i.postimg.cc/Y0YWdW37/DSC-9160-0219.jpg (https://postimages.org/)

In this photo you can see how the leads to the warning light plug onto the positive and negative pins on the battery port of the receiver. This allows me to completely separate the top and bottom body parts if ever needed.

https://i.postimg.cc/4xBh2ZzY/DSC-9161-0220.jpg (https://postimages.org/)

plug the switch leads back together.

https://i.postimg.cc/d03ZzXB4/DSC-9162-0221.jpg (https://postimages.org/)

Install the battery and plug it in.

https://i.postimg.cc/7Zx2NbTv/DSC-9163-0222.jpg (https://postimages.org/)

Turn on the transmitter and then flip the master switch and see if everything is going to function. Hooray, Success, let's button this thing up.

SNAG #2 - I started to put the top body section in place and ran into a problem. The right hand side would go together just fine but something was keeping the left hand side from closing, not even close. A quick look down the hole under the drivers seat showed what the problem was. When I checked the clearance between the back of the switch and the receiver earlier the servo leads were not connected. I thought I had enough clearance but because of the size of the XT30 connector I was binding on those servo leads. What to do after I was so close to being done? After a little thought the fix was simple. Pried the receiver off the double sided servo tape and scrapped the tape off the inside of the body. Man that stuff sticks! I then turned the receiver 90 degrees counter-clockwise, moved it over towards the wheel housing and pushed it downward as much as it would go. plenty of clearance. And sorry, but I didn't think to take a photo at this time showing this but if you look at the photo above showing the receiver with everything plugged in and visualize it turned on it's side you'll get the idea. plenty of clearance for the switch connector now.

Alright, put the top back in place, line it up and push it home and , wait, what??? Everything fits except the very back end won't quite go together. Oh for the love of....

SNAG #3 - Remember the clearance problem I talked about above that forced me to relocate one of the ESCs? Well turns out there's even less room between the top and bottom parts than I thought. I have 3 servo cables lying across that area and they are each only about 1.25mm thick. Apparently there is not even that much room as the cables were keeping the top slightly raised. I could have just squeezed the top and bottom together but I didn't want to put the wires under that kind of pressure. I could have rerun them around the front of the wheel housing but was concerned about generating noise by running more wires that close to an ESC. The fix is simple but frustrating. Very carefully thin the top and bottom body parts in the area where the clearance issue exists.

The next two photos show the areas that are the problem and need to be thinned.

https://i.postimg.cc/449VfDT0/DSC-9159-0218a.jpg (https://postimages.org/)
https://i.postimg.cc/YSdfFYXy/DSC-9093-0036.jpg (https://postimages.org/)

Pulling the servo cables off the receiver and moving them out of the way I started thinning by first using a motor-tool on the steering mount to bring the thickness on the left of the steering servo down to match the original body. This can be on a taper. Be careful not to grind the back edge of the part as that will show on the outside. Then using a flat riffler and sanding sticks I slowly thinned the top and bottom bodies in the areas shown above. Taking a little bit off, try the fit, take a little more, etc. until the top and bottom came together. I then rounded the sharp edges where the servo cables ran to minimize stress on them. Fortunately There was plenty of plastic left So I don't feel there is a breaking or cracking hazard. But be careful if using a motor-tool so you don't cut through the body.

You only need about 1.5mm clearance in this area. If you build one of these fork lifts following my process, I would remove the material in this area back when I cut away all the other plastic that has to be removed. An easy way to measure the clearance would be to put a small ball of clay or similar material between the two halves before putting them together and then measuring the height of the squished ball.

So, did it finally go together? Yes, hallelujah, success at last! One final step, install the operator's seat.

https://i.postimg.cc/sDPWS5x9/DSC-9164-0223.jpg (https://postimages.org/)

This was an incredibly fun conversion and I am very pleased with how it turned out. Took some experimenting, some designing, some fabrication and a lot of just looking and thinking. Everything I love about this hobby.
If you decide you want to do one of these conversions please post up your results, especially if you do something different. Feel free to add it to this thread if you want. More than one way to skin a cat. Speaking of which, have you noticed how many different ways people have come up with to convert the Bruder D5? Now I've got to figure out how to modify the back of my flatbed trailer so I can haul this thing down the road.

[frizzen]

That came out awesome!

Oh yeah, always gotta love those hidden clearance problems between halves, that don't show up until the end, so you've gotta strip it all back down to fix it.

[dremu]

Beautiful work! And a fun toy, err, project =))

If you have a minute, I'd be obliged if you could post up dimensions of the thing (not counting the forks.) I'm curious how it compares to my wildly mis-scaled scratch build. I suspect the Bruder is smaller, which as discussed gives one all kinds of engineering challenges.

-- A

[Zabco]

Thanks, was a very fun build.

Front to back of body is 4-3/4 in. Outside tire to outside tire is 6-3/4in. Ground to top of body is 3-1/4 in. Ground to top of ROPs is 5-1/2 in. Ground to top of fully raised mast is 8-3/4 in. Tires are 1-5/8 in diameter. Bruder toys are nominally considered to be 1:16 scale. However I have some 4'x4' pallets and oil drums accurately scaled to 1:14 and they fit perfectly between the front legs just like they would on a life-sized machine. So who's to say what scale it really is.

[dremu]

Holy carp, okay, that's insane then that you got all that in there!

My "1:10ish" is about twice the size of the Bruder. I sized it so that it would lift onto the bed of my trailers, and some fudging may have occurred =)) Certainly makes it easier to fit the electromechanical stuff though.

Thanks and kudos again.

-- A

[Zabco]

UPDATE

The forklift has worked well since I posted this build. There were a couple of issues though that I felt needed to be addressed. First, when I put this together I felt that I should have both the forward / reverse travel and the steering on the left stick leaving the right stick solely for up/down mast movement. This hasn't really worked out. At very slow travel speeds while trying to line the forks up with the intended load it was very difficult to not accidently knock the steering too far one way or another. So I decided I would be better off moving the steering over to the right hand stick. Not a big deal, just have to open up the body and swap a servo lead from one channel on the receiver to another. I wasn't really wanting to open this model up just for this though as it is a bit tricky getting everything lined back up to get it back together. But if I was going to open up the model I may as well try and take care of the second issue also.

The second Issue, as I noted above in the original build articles, is that this forklift is very light and simply cannot lift a heavy load without tipping over. That's fine, I realized this from the beginning and only wanted to to be able to lift a scale pallet with four oil drums as the heaviest load it would have to handle. But even as light weight as this load was, when the lift mast was in it's full forward position it would take enough weight off the rear drive wheel that it often could not get enough traction to move the forklift depending on the surface. Really needed to add some weight to the back of this model. I had earlier added some lead shot to the inside of the Bruder rear tire but it just wasn't enough extra weight. So I started looking for some additional weight that I could add into the available space. If you look back at the earlier photos you can see there just isn't much room left inside. So the weight needed to be heavy for it's size and thin. What I finally came up with was a self-adhesive lead tape that golfers use to add weight to the heads of their clubs. I'm not a golfer so I didn't know this stuff existed. It's great for this purpose as it's only about a 1/16th of an inch thick, very pliable and easy to cut to any shape needed.

Attached are a few photos showing where I put the lead tape in the rear of the forklift. Basically a piece was attached to most every open flat space that could be easily reached. On the tape mounted behind the receiver I did also put some electrical tape over it as the servo pins on the receiver I used are exposed on the rear and I didn't want to risk a possible short circuit sometime down the road. On the right rear side there isn't a lot of space so I put two layers of the lead tape there. I didn't weigh the tape so I don't know exactly how much weight I added but It was enough that the drive wheel now stays firmly in contact with the ground with the loads that I use. I also now have much better control of driving and steering. I took the forklift to the Indianapolis meet in April and it performed very well.

Underside of top half of model:
https://i.postimg.cc/bN6RX5Qy/DSC-9630.jpg (https://postimages.org/){/img}

Bottom left showing tape installed behind receiver:
https://i.postimg.cc/0yFdjJWh/DSC-9631.jpg (https://postimages.org/)[/img}

Bottom right side:
https://i.postimg.cc/L8n3mVTz/DSC-9632.jpg (https://postimages.org/)[/img}

[frizzen]

How much does it feel like splitting Drive and Steer helps with the control?

With my fork i'd wondered about setting up some switched dual-rates for the throttle channel so i could
switch between "travel across warehouse'' speed and "do not knock over a rack" speed

Great find on the golfer lead tape! That looks like a great solution

There was an rc meet in Indianapolis in April???

[kerst]

very interesting!

Kerst

[Zabco]

How much does it feel like splitting Drive and Steer helps with the control?

It's helped me quite a bit. My original concern was that trying to raise/lower mast while driving might cause steering problems. But I've found that the only time I really do that is when I'm trying to line up with a load that is on the flatbed and then I'm moving forward pretty slowly anyway. Almost all the rest of my equipment is set up for forward/reverse on left stick and steer on right stick so that's what I'm used to.


There was an rc meet in Indianapolis in April???

Yep, was a one day only event on Saturday the 2nd at the Boone Cnty Fairgrounds. Wondered why you weren't thre.

[jffhrvstr]

That is some impressive work.

[Zabco]

Thank you, it was a very fun challenge.