Dragline Crawler Build

[Rvjimd]

For a few weeks now I have been learning how to run my new bench sized mill and lathe and loving it! I have always wanted to scratch build a dozer and my first big project is building a crawler undercarriage for my NyLint dragline conversion. My conversion was completed last fall but I never got the truck powered. Thanks go out to Jared and Steve for all the good info in Jared's thread of his BE 22 build.

Here are a few pictures of my crane and the track pads so far. I have gone through at least four variations of pad designs to get one I hope will work well and still look "sort of" scale. Paramount in my project is to have it look good enough but also not make production of parts to complicated.

http://i1291.photobucket.com/albums/b554/Slotcarjim/f3dc4591965adb208fc01f331f6a359d_zpsyfjlu3j2.jpg

I believe the scale is 1:16 on the crane and I tried to eyeball the pads against crane and adjust the drawing Steve posted to get some reference for other parts. The second pad from the left is most similar to my final design choice. I will be using 1/8" x 3/4 x 1.5" aluminum bar stock. I messed with some thicker material but it was a pain to machine the detail of the drive dog ears on the top of the pads and I found a way to use 1/8" and still have the drive dogs.

http://i1291.photobucket.com/albums/b554/Slotcarjim/aafd7c9df61faecfaf491dbc17aeb8a4_zpsv8c4dz1x.jpg

This is a stack of the pads that I am NOT going to make. The "third dimension" of the drive dog ears on top of the pads really added a lot of extra steps and problems to the machining operation, like issues of holding the part and just extra machining steps.
http://i1291.photobucket.com/albums/b554/Slotcarjim/6997723a232ff8e462813b6d1f4ff793_zpsuziplg6f.jpg

This is the drill guide I made to locate and drill the holes in the pads.
http://i1291.photobucket.com/albums/b554/Slotcarjim/dda6eac79bb934fd35de57dc4694d6c7_zpspzp225vz.jpg

I need to adjust the drill guide to perfectly center the holes on the pads and then I'm ready to start making a bunch of these things!

Jim

[Rvjimd]

Here are a few more pics. These are my final choice on the design and you can see I am looking at the pitch of the tumbler and pad links. I will make an actual drive tumbler and mill the drive dogs into the side of it on the outer radius. With the pads wrapped around the idler it looks like it should work.

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG0928_zpswyilrtth.jpg

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG0931_zpsjrimpsh1.jpg

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG0932_zpsppvqzejj.jpg

Jim

[modelman]

Nice work jim-I know what you are dealing with. Making those drive dog ears on the pad adds a lot of machine work. I spent a week+ making one pad perfect and that is why I made a mold and cast all of them. I'm sure you noticed the pitch changes as you transition from flat to the circle and that was the tricky part for me making the drive sprocket. Never got it exactly right. Looks like you have it figured out. Keep the pictures coming.

[Rvjimd]

Tom,

Thanks, I thought I read a comment you made on another thread about the pitch, so I was aware of that going in. That would be a real issue if you didn't realize that and made a bunch of parts and THEN figure that one out! :(

Jim

[Rvjimd]

Got a batch of pads mostly finished. Still putting the slot in middle that receives the drive dog part. And, I still need to drill the hinge holes. Going to be fun and should start to go faster once I get all the pads finished.

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG0938_zpsg4k7dyqn.jpg

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG0937_zpsj5uj5hyo.jpg

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG0936_zpsbp2kes5q.jpg

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG0935_zpsjlqazpgg.jpg

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG0934_zps6cpdshyb.jpg

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG0933_zps945tuezr.jpg

Jim

[modelman]

Looking good jim, but I am puzzled by one thing :confused:. The pads look to be about 1/8" thick so why didn't you just use 1/8" flat stock and avoid all that milling. Am I missing something?

[Rvjimd]

Tom, the stock is 1/8". I WAS experimenting with 1/4" stock where I machined the dogs on the one side but that was a lot of extra work. With the current pads pictured I am milling the leading and trailing edge hinged slots as well as the short slot on the one side to accept the little channel part that becomes the drive dog. I hope that clears it u a bit?

Jim

[Jared]

Looks like you've got it figured out, Jim. I'm planning on using brass for the pads and soldering the lugs on. I like your drilling fixture.

[Rvjimd]

Ah, ya the brass would work good I bet, nice and heavy too where you want it.

Jim

[modelman]

Okay jim-now I got it. You were showing pictures of the pads that you were milling the drive dogs in. I thought you were milling all those chunks down to 1/8". Do you have a plan for making the drive dogs? That looks like really small pcs. to make individually.

[Rvjimd]

I have been out of the shop for awhile but before I left I DID get the pads all finished and started assembly. I wanted to check my pitch and it is close but I am going to have to turn a few more tumblers to get one perfect. I used the rotary table to hold and drill a bolt circle and simply used brass tube to check the diameter and pitch match between the pads and the tumbler. Here is a picture to show my first test tumbler. If anyone has tips or info on this type of thing I am all ears, I am not a machinist, engineer or designer. I'm just trying things until it looks okay and works reasonably well...:p (Tom, I hope you are reading this... ;) )

http://i1291.photobucket.com/albums/b554/Slotcarjim/e1ce3abbadac2a4cff78d07a01036ffe_zpspuxb9dv2.jpg

Jim

[speedy8305]

Great progress cant wait to see the end result im sure it will be killer

[Wiskybilt]

Jim, check out this link, it should help clear up some. If I can help anymore let me know some of your deminsions that you are bound by.

http://www.engineersedge.com/gear_formula.htm

[Wiskybilt]

Ehow instructions for circular pitch...

Instructions
1
Measure the gear's diameter. For this example, imagine a diameter of 6 inches.

2
Multiply this answer by the constant pi, which is approximately 3.142: 6 × 3.142 = 18.852.

3
Divide this answer by the number of teeth around the gear. For example, if the gear has 28 teeth: 18.852 ÷ 28 = 0.673. This is the gear's circular pitch, measured in inches.



Read more : http://www.ehow.com/how_8660734_calculate-circular-pitch.html
You might start by wrapping the hub with the track and counting how many cogs you need.

[Rvjimd]

Ah, I knew there must be a formula for this. I am just now reading your post, so I will apply the formula to my current parts and see how it compares and then adjust and make a new part.

I don't really want to make the tumbler any larger, so this information should help a great deal!

Thanks,

Jim

[Wiskybilt]

YW, it looks like another cog or two might do it on the same diameter.

[modelman]

Jim-welcome to the world of old shovel style tracks. This was a nightmare for me, but after many ruined parts I made it work. I don't think this formula will work for you because you have already determined your pitch by making the track pads first. All I can tell you is what I did. I think you need to wrap your pads around the sprocket and measure the pitch in the circle. Of course it will be different than with the pads lying flat but You will need to set the pitch that will work on the circle and in the transition from the flat to the circle. This is the tricky part. If the pitch is perfect for the circle the drive dogs may catch on the edge of the sprocket cut out. If you cannot make the math work on degrees you may have to change the dia. of the sprocket and this is where the never-ending circle begins. You may have to angle the sides of the drive dogs and put a greater angle on the sides of the sprocket grove to keep the drive dogs from catching on the edge. You may also have to round the top corners of the drive dog.Here is a diagram-
http://i305.photobucket.com/albums/nn216/modelman/Boat%20pictures/test%20pad%20and%20sprocket_zpsh5a9vx61.jpg
You may also have to have divider plates for your rotary table depending on how the math works. Good luck-hope this makes sense.

[RCP57]

This could be totally wrong but it worked on my Bruder dozer conversions. I took the chain pitch in my case- 0.375 and times it by the number of teeth I wanted. This number gives you circumference. Divide that by pi (3.14) which gives you diameter. Then divide this number in half which gives you(radius) the distance from center in which you need to cut the teeth. Divide 360 by the number of teeth and that's how many degrees apart they need to be. Use an end mill or drill bit to pop in the appropriate amount of teeth. For me making regular sprockets I then go back over them with a slightly larger cutter moved outward on the teeth. This gives the tips more angle to clear as the chain moves on and off of them. Clean them up a bit with a file and I'm good to go. It should be noted that your disc of metal needs to be slightly larger than your intended pitch circle for this to work. Hope this works if nothing else makes sense.

[Rvjimd]

Tom,

Thanks. I thought I would probably need to angle the drive dogs on the pads. I have dividing plates so I can try that if it comes to that. I think I might start by just making a few more samples and make them a bit smaller each to see if it get better.

Also, I figured it would be simple to just drill the holes like I did and use brass tube to see if it looked close. Then, if I get where it looks like it should work I will make an actual tumbler and mill it to look like it should.

Jim

[Rvjimd]

Reg, yea, that does make sense, thanks

Jim

[modelman]

This could be totally wrong but it worked on my Bruder dozer conversions. I took the chain pitch in my case- 0.375 and times it by the number of teeth I wanted. This number gives you circumference. Divide that by pi (3.14) which gives you diameter. Then divide this number in half which gives you(radius) the distance from center in which you need to cut the teeth. Divide 360 by the number of teeth and that's how many degrees apart they need to be. Use an end mill or drill bit to pop in the appropriate amount of teeth. For me making regular sprockets I then go back over them with a slightly larger cutter moved outward on the teeth. This gives the tips more angle to clear as the chain moves on and off of them. Clean them up a bit with a file and I'm good to go. It should be noted that your disc of metal needs to be slightly larger than your intended pitch circle for this to work. Hope this works if nothing else makes sense.

Your math is good but chain drive pitch never changes. This type of track pads with the drive dogs coming up from the center causes the pitch to change when it goes around the sprocket. He can work it out with a few practice cuts (maybe).:D

[modelman]

Jim-you have the right approach. I made sample pcs. from anything I could find that was soft. Actually delrin works great. It machines good and is easy on your tooling. I made my final sprockets from delrin and they should last forever.

[Rvjimd]

Yea, I have some white, but black would look pretty good as well...

Thanks

Jim

[Rvjimd]

I think I got it. I think part of my trouble was understanding the darn DRO and bolt circle function. I made a new tumbler blank the same diameter and put one EXTRA hole (10 holes) on the first sample and that was obviously not right. My first one had 9 holes and it was close but not quite correct. So, I flipped it over and tried 8 holes, which is what I thought I was going to try the very first time, not sure what I was thinking then?

Anyway, 8 looks pretty good. I'm going to move on to making the side frames and see if I can get a motor mounted to an axel shaft and then I will really be able to see if it is close enough.

http://i1291.photobucket.com/albums/b554/Slotcarjim/26066b4fdc44d903fb1379a01c8548b7_zpsu2zuh1rv.jpg

Jim

[Wiskybilt]

Jim,
It looks like all the pressure is only going to apply to one cog at a time. Shouldn't it apply to all the cogs evenly, same as a track chain on a dozer? Just a suggestion

[Rvjimd]

I think in the last photo the bottom pad is loose allowing slop at that drive dog. When I hold them snug they all impact pretty good. I plan on some sort of spring tension system on the idlers.

Jim

[RCP57]

Your math is good but chain drive pitch never changes. This type of track pads with the drive dogs coming up from the center causes the pitch to change when it goes around the sprocket. He can work it out with a few practice cuts (maybe).:D

Good point! I hadn't thought of that.

Looks like you have it figured now anyway Jim!

[Wiskybilt]

Good to see your getting it all working. Looking forward to seeing the rest of this build

[Wiskybilt]

https://m.youtube.com/watch?v=2lPNqn8LU4Q Found a very informative series of videos on gear cutting, thought I would share. This is what I watch instead of prime time tv.

[Rvjimd]

Wsky,

Ya, I have watched that one as well a bunch of other gear cutting videos. I haven't done it yet, but that is certainly one of my future projects for the mill and the dividing plates on the RT.

Modelman,

If you have other drawings you want to share that would be great! I really wish I had a PC and CAD software and here is the biggie, the knowledge and patients to learn how to use a CAD program.

A lot of the reason I like to post project builds like this one is because it keeps me motivated. Here is the setup I am using to drill the link holes in the pads. They are pinned together with 1/16 brass tube. I had been drilling these holes on the drill press but the chuck is a bit off and I decided to try making a bit holder for a 3/8" collet to put into the mill. I have a R8 drill chuck for the mill but it won't close down small enough for a 1/16" drill. I just turned a piece if aluminum in the lathe and center drilled it 1/16". It us turned down to fit a 3/8" collet which is a common size for me for end mills so I can switch between them without changing the collet. The 1/16 bit is a good slide fit and I glued it in place with CA.

Remember, I am a "noob" machinist so don't be afraid to offer tips or observations on my techniques.

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG0948_zpsntgrbwxj.jpg

Jim

[9W Monighan]

Jim, Get me some dimensions. Maybe I can draw what you need and figure out your pitch problem.
You may want to shorten that drill some. or use a center drill first to spot drill first. That 1/16 drill probably walks around when you try to start a hole.
I have a drawing from one of the Silver Spades track pads that may give a better idea how the tumbles engage.

[Rvjimd]

Steve,

Thanks for the offer, I don't think I know yet if and how much of a problem I have. I need to finish riveting on the dog ears and make up a side frame and try it as a complete assembly. At this point I am still optimistic.

Good idea on shortening the drill! I just checked my drill guide and it was not quite square so I milled it a bit. My inside holes where not quite center because the guide was leaning over a bit.

Jim

[modelman]

Jim-I know nothing about CAD drawing. I am using a simple, free program I found online. It is easy to use and can be accurate with measurements. Do you have a way to hold the brass pins in place? Just a suggestion-use music wire-it is available in sizes .060",.062",.064" etc.. You could drill one side of the pads for a press fit and the other side for a slip fit and the pins would stay in place. Maybe you have all this figured out. Keep working and posting pictures-

[Rvjimd]

Tom,

I wanted to use brass tube or solid brass so that it wasn't as hard as steel. I would rather replace the pins vs making new pads as the holes wear.

I was thinking about just putting a spot of glue on the outside end of each pin? I don't want the to be too hard to remove, I think maybe CA glue would be okay, I can heat it up and get the pins out as needed.

Been trying to finish up the drilling, then I need to do the little dog ears.

Thanks for your interest! It keeps me motivated, it is easy to get bogged down bay the shear number of parts I'm making...:o

Jim

[Wiskybilt]

First, I am wondering, and it's going to be a simple answer I'm sure....probably make me bang my head and say, of course. But, what is CA glue?
Tom,

I wanted to use brass tube or solid brass so that it wasn't as hard as steel. I would rather replace the pins vs making new pads

Jim

Sounds like a working model, no shelf queen here. My favorite kind!

On the long drill bit... You can buy stubby drill bits, they don't walk as easy. And like 9W said, if you spot or c-drill first, it will keep your parts more reliably consistent. And the drill will drill straighter as well.

[Rvjimd]

CA - cyanoacrylate. It is crazy glue and a bunch of other names.

I just used the dremel tool and shortened the bit a bit. :p with the drill guide I am getting a pretty good and well located hole now. I have to be careful, if they start to wander off center the pads develope a twist as they get pinned together. It is sort of an interesting problem, since I drill one end and flip it to the other end and side. So, any off center issue is doubled and then the twist sets in.

Jim

Jim

[modelman]

Jim-I will keep watching. This is the only build going on here that I am interested in. Before your drill guide gets to loose and off center maybe you could drill it out and press a brass tube inside it. The brass possibly will last longer than the aluminum. If the holes get off center the pads will be a mess. Ain't machining fun!!!!

[Rvjimd]

Tom,

Good idea on the brass bushing. I have basically checking every one I drill. I had been thinking if the cap in the drill guide starts to hog out I would make one in steel, but a brass bushing sounds easy.

I was getting crazy drilling holes and had to do something different for a while! If all the side rails turn out okay I will try to make them in steel to add a bit of weight. I'm thinking I may also add some lead ballast where I can as well.

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG0951_zps9psn1jtm.jpg

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG0952_zpsvejjkkbg.jpg

Jim

[Car5858]

I am also available to help with cad drawing if needed. Just send me a PM with the dimensions you need.

Nice work and I will be watching this thread for the duration :)

[Rvjimd]

Car5858, thanks for the offer! I'm using some photos of drawings that .steve posted on another crane build, for now that is getting me by.

Tom,

This picture is for you, I had to adjust it after I put the bushing in the cap, but it makes it easier to see and should last at least thru the remainder of the pads I have to drill. ;)

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG0953_zpss9r90fcu.jpg

Here is a side view of a drilled track pad.

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG0954_zpspziimgct.jpg

]

Jim

[Wiskybilt]

Looking great Jim! I like the progress and constant updates. Keeps the interest up!

[Jared]

Those pads look great, Jim! Keep it up. You're getting me thinking about finishing out the back half of my 40' container so I can set up a my stuff and get working. Be a great winter project.

[Rvjimd]

Got four side frame rails made and bolted two of them together. Oh, and if I counted correctly, I got all the pads drilled yesterday. Now all I have left on the pads is riveting the drive dogs into the slots. The pads detail never ends! ;)

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG0957_zps9hbwzuim.jpg

Ya, I need to find some better looking hardware to bolt them together...

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG0959_zpsny1gnxxs.jpg

Jim

[speedy8305]

looking good

[Wiskybilt]

Very good Jim, those high production parts sure do get monotonous

[Rvjimd]

Here is my simple fixture to drill the little sections of channel that get riveted into the pocket in each pad.

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG0961_zpsteevemtv.jpg

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG0960_zpsq75ua9lt.jpg

Jim

[modelman]

Looking good jim- to me the pads are the most tedious and time consuming job on these types of projects. Once you get those finished you can have some fun milling all the other parts. Are you using a center drill to spot each hole?

[Rvjimd]

Here is a shot of the micro stop counter sink tool and pneumatic rivet squeezer. I have a bit of aluminum metal work experience and already had these tools, or I would have NOT attempted to do the pads like it did. I countersink the hole in the bottom of the pads to accept the rivet flush.

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG0962_zps5sgk2ts5.jpg

The micro stop is fine threaded and allows adjustment so you can get a perfect depth on the countersink to fit the rivet head. I left them a bit high because I didn't want any extra rivet on the inside to get in the way of the tumblers. And, the little channel parts are so small and the hole clearance is way less than it should be so setting the rivet to standards can split or crack the part. I could have used a soft rivet here but had a bunch of standard.

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG0963_zpsh32ogsxb.jpg

Here is the rivet squeezer, really handy of you have a lot of rivets to squeeze.

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG0964_zpstf8rgak1.jpg

Closeup of the dirt side of one of the pads with the rivet set.

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG0965_zpsnysnkqkx.jpg

Jim

[modelman]

Nice work jim-it's good to have the tools you need.

[Rvjimd]

Parting off one of the spacers for the pairs of side frame rails.

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG0966_zpsthvkijgp.jpg


I changed my side rail design a bit, should have one set finished tonight...:rolleyes:

Jim

[Rvjimd]

Got enough finished to do a first check of the "scale" of my undercarriage to the crane.

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG0967_zpsntl794vd.jpg

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG0968_zpsceossdon.jpg

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG0969_zpswt9tuarr.jpg

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG0970_zpstrpkkksy.jpg


Jim

[Wiskybilt]

Just about ready to take a walk

[modelman]

Your scale looks good to me jim. Are you happy with it? I like the new frame rails you made. Adds strength, which you probably don't need but it helps the appearance. Are you about ready to make a tumbler and see if this works? Keep cranking on those handles. :D

[Rvjimd]

Thanks Tom! Ya I am pretty happy with it. I did the side over just for a better appearance. I have a hard time visualizing stuff like this so I always end up making something to see how it looks and then usually make one or two more until I am happy with it.

I am hesitating on the tumblers only because I don't want to take the vice off to put the rotary table on and then I know I will be going back to the vice. It really isn't a big deal, but I am trying to do as much as I can before the switch over.

Decided to put a .050" groove in the bottom of the rails to "hold" the lower rollers.

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG0971_zpsqux9jdks.jpg

Thanks to ALL for watching! :D

Jim

[modelman]

I know exactly what you mean about changing set-ups. When I got my 2-in-1 machine several people told me I would regret it but the price was just too good to pass up. However, I thought about what I was told every time I was turning something and needed the mill for 1-simple cut and had to change over again and again. Oh well, live and learn.

[Rvjimd]

More progress shots! Decided to leave the lower roller shafts round and make little clamps for each end. Will attach them with 2-56 cap screws. Made a little die to form the strap clamps. Turned the 3/16" steel rod down to fit a 3/16" brass bushing to go inside the rollers.

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG0981_zpsdd2nvq4d.jpg

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG0980_zpsuoran3um.jpg

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG0979_zpsrxzljvo4.jpg

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG0976_zps1aksaxrf.jpg

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG0977_zpsxxgz73ay.jpg

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG0978_zpsipr5s3hq.jpg

Jim

[Jared]

Looks like that undercarriage will fit real nice underneath the house, Jim. On those rollers, you might want to bevel the edges that will run between the lugs on the track. That way the roller won't be able to catch the edge of the lug, ride up on it and throw the track off.

[Rvjimd]

Jared,

Good idea on the roller profile. I need to make all of them, the one in the photo is a prototype. I will put a nice big angle on the corner of them.

QUESTION: How tight should the rollers and tumblers fit between the dog ears on the pads? Not sure if they should be close or real sloppy narrow?

Jim

[Trucker_Jo]

Very cool! I have always wondered if someone was ever going to build an older track style like this, and it looks like you're knocking it out of the park..

[modelman]

Looking good jim-that is a nice beefy press you made. I agree with jared on the rollers, just a slight chamfer on the edges should help. I say you need some clearance between tumblers, rollers, etc.. This allows for dirt not jamming the parts. 9W may know something about this.

[Rvjimd]

Not too much "visible" progress today but I have actually gotten a bunch done. I wasn't happy with the brass pins linking the pads so I decided to try taping 2-56 holes in the outside tabs and drilled a clearance hole on the inside tabs. The only 2-56 screws I had are shown in the picture. They don't look too bad although a bit big looking I think. I ordered some button head and some plain set screws. I will try those and decide which way to go.

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG0984_zpssnjx3mcl.jpg

If I had made this decision earlier i think I would have milled the pads such that there was a shoulder in the outside to let the head of the screw sit flush with the outside edge of the pad.

Jim

[Rvjimd]

How would you make these idler rollers?

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG0987_zps1brs6kxs.jpg

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG0986_zpsybdtjckg.jpg

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG0985_zpsdeshdnjs.jpg

I need to make 12 of them. I am starting with 3/4" round aluminum stock. They have a taper to help clear the drive dog tabs on the pads. This is one of those things that I look at and think " that shouldn't be too hard", and then when I start making them I end up with two or three and NONE of them are the same. I had been trying to make the taper using the side angle on my right hand turning tool bit, but that is problematic when it comes to doing the second (or left hand side if the part stays chucked up for the entire process, which I think it should). So, now it finally dawned on me, use the compound to make the taper.

My problems are:

Keeping concentricity. (I think I solved this by NOT over drilling the center hole, so that when I pull the stock out, I don't start off on the next part with an off center hole.)

Getting the same length on the shoulders on each side.

Getting the center rib in the center.

I am using my dial indicator on a mag base to move the carriage in as I turn the shoulder.

Should I be doing this with the part chucked once for the entire part? If so, should I be using a left hand turning tool for the left hand shoulder and Turing away from the chuck?

I think this all comes back to one of my very first questions when I got started with the lathe, "how do you know what steps and what order and how to decide what tool or procedure"?

Thanks for any tips or suggestions.

Jim

[9W Monighan]

Keep the bar chucked through the whole process. Leave enough bar sticking out of the chuck so your tools can do what is needed for say,2 or 4 rollers. Turn the OD , do the step and taper using LH and RH tools, center drill, rough drill, ream to size you need, part off the finished roller making sure the left and right are equal so rib is centered. Now this process will keep everything concentric but don't drill too far because when you have to pull the bar out of the chuck to machine more you will have to face the bar off so it's clean to start another center drill.

[andyathome]

I sorta have the same issue, but am thinking of taking the easy out and uesing some 5mm bearings instead of making lots of rollers as they will sit nicely in my K1 track.
By the way progerss so far is looking realy good.
cheers andy

[modelman]

Jim-I think everyone would agree on this. Practice is the best tool. Get to know your machine, find out the problem areas and learn how to work around them. You are doing great so far. Keep working and enjoy!!

[Rvjimd]

Thanks guys! I think I am going to start working on a drive tumbler while I wait on my 2-56 hardware to arrive. I figure if the diameter of the tumblers change so will the idler rollers so better wait on them until I know I have a tumbler that fits the pad links.

Jim

[Rvjimd]

And now, for something completely different...

Here is my first prototype drive tumbler! Still working out the details.

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG0988_zpsngsfssok.jpg

Don't even have the second side formed because I didn't leave enough center hub to hold onto. Back to the lathe...

Jim

[Rvjimd]

Finally got one tumbler done both sides. I am waiting on hardware so I can assemble an entire unit. Need to have it nearly complete so I can tell what I need to do to the drive dog ears on the pads and the tumbler flanges.

I am pretty sure I am going to need to put a bevel on both, just not sure how much on each. I sure it will be more trial and lots of errors.

http://i1291.photobucket.com/albums/b554/Slotcarjim/9e7aaaf6236234d93fdf83544e426346_zpszhw2kneu.jpg

Jim

[Rakthi]

Hi Jim, brilliant how you learn as you go and sort out the problems as they come. Learning a lot just reading about your trial and errors. Many thanks for documenting the process.

Cheers!
Stephan

[Rvjimd]

I am planning to drive the crawler with chain and sprockets like a full scale. I am thinking about ordering some of this .1227" plastic chain but it says 14lbs tensile strength. Is that is way to weak! I don't have a good feel for that in this application.

https://www.servocity.com/html/plastic_chain__0_1227__.html#.VX7XXXA8KrU

Is it okay to post a link like this or is that a no-no?


I already have some .25 inch stuff, but I haven't found sprockets small enough yet. I'm gona need about 7/8" for the large sprocket at the tumbler and something smaller at the motor.

Stephan, I get a bit out of the process too. The other day I was about to make some more little tabs that rivet into the pads. I was starting to clamp them into the mill vise and remembered that I had that little fixture block. I went to my thread just to recall the size and shape of the block to make it easier to find in my pile of stuff!


Jim

[TRUCKMAKER]

Jim,
Check this out and see if its what your looking for:

http://www.mcmaster.com/#miniature-roller-chain/=xmuspu

[modelman]

Jim-your thinking is right on with this. The dia. of the tumbler dictates the size of all the other parts. You may have some work to do on the tumblers but I think you are on top of that. Personally, I would go with the metal chain but finding the really small sprockets may be a challenge. Does the 1/4" chain look too big? You might find something smaller in some clock works sites-not sure. Keep the pictures coming.

[Rvjimd]

Truck maker, thanks for the link. I always forget about McM for parts. I just seem to get stuff other places.

Tom, the .25 looks okay. Maybe just a bit big but not too bad. The common 10T sprocket would even look okay next to the tumbler but I might have to search for a smaller one on the motor.

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG0991_zps3g0mtemq.jpg

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG0990_zpscd31mqmv.jpg

The little pulley I have in the photo is about the size of the smallest sprocket I have found so far.

Jim

[modelman]

Jim-if the 10-t sprocket is okay for size then maybe you could use the same on the motor. When you get a little farther along you can turn the assembly and calculate the speed you need and get a motor that speed. If you get a slow motor it should have a lot of power. Just a thought- keep at it!!

[Rvjimd]

Decided to bolt up both sides again so I took a few more shots.

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG0992_zpsoyw2lm5j.jpg

Shaft coming out the wrong side here, but no problem yet...

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG0993_zpsqjniwuox.jpg

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG0994_zpsgti5cm7j.jpg

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG0995_zpsjwx1dbyn.jpg

Jim

[Rvjimd]

Slip ring? Has anyone tried a DIY slip ring? I have repaired one on a in motion servo satellite reciever and I am thinking about trying it. I guess I haven't looked online yet to see how much they are and how it would fit into the UC?

One of the things with my particular install is that there "should be" a 1/4" shaft in the center of the bed that the upper house centers and pivots on. This way it matches the truck frame, in case I want to switch back to the highway truck chassis.

Jim

[doodlebug]

Look for some # 25 chain, http://www.amazon.com/Koch-7425100-Roller-Chain-Feet/dp/B004HKITHA Just saw a refence, that scooters use it. http://www.electricscooterparts.com/chain25.html I have a 9 tooth sprocket for a project, can't remember where I bought it 25 years ago. http://www.surpluscenter.com/Power-Transmission/Sprockets/Finished-Bore-Sprockets/9T-1-4-BORE-25P-SPROCKET-1-2742-9-A.axd
Cheers, Neil.

[Rvjimd]

I got some of my Enco order today and it had some of the 2-56 screws I was waiting on. I think I can shape the ears on the pads and get smooth operation.

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG0996_zpsgudciphq.jpg

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG0997_zpszveqqcsz.jpg

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG0998_zpscsggxqyg.jpg

Jim

[Wiskybilt]

Those tracks are so cool! I like that old iron

[modelman]

Jim- isn't it nice to see all that work finally shape into something. Looks good, although that 2nd picture with the close up of the tumbler is confusing to me. The pitch looks good except on 1-pad. That I don't understand. I think all you can do is finish the pads and see if it turns. Hope it works for you!!

[Jared]

Wow, those tracks look great! Are you going to put any rollers on top of the side frames to hold the track sag up?

[Rvjimd]

Jared,

Thanks! I was waiting on the 2-56 screws so I could assemble a complete set and start checking the pitch and freedom of operation. I do plan on 6 lower and 2 top rollers. In fact, I think they should help keep the pads and tumblers in line for better operation. Been working on the tension system brackets and mount.

Jim

[Rvjimd]

Working on one of the MANY small details. Trying some delrin for the shaft on the idler tumbler.

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG1000_zpsmtw0crhw.jpg

Jim

[Rvjimd]

Going to redo the tension system. I wanted to use 4-40 but the wheel collars happened to be 6-32 which I think looks too big.

Just putting on the tensioner even without the proper setup helps control the runout and makes me think if I get it all lined up, add the upper and lower rollers and get the tumblers refined a bit more that I may actually get a working unit.:p

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG1005_zpsr0g92heg.jpg

Jim

[9W Monighan]

Looking good Jim. Hope to see it in about 6weeks.

[modelman]

Nice work jim-good to see you back at work on this. Is it far enough along that you can turn it?

[Rvjimd]

Brief update:

I once AGAIN made new side rails. Decided to try putting the tension adjusters thru the end of the beam and thread into the axel shaft on the idler tumbler. I like this design, the brackets on the outsides were difficult to the size down so they didn't look out of scale. I might have to drill a few pads with access holes to get at the adjuster screws.

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG1006_zpsf100mqwd.jpg

I drilled and taped the drive tumbler and powered it with my drill. I still have an problem with the pads shifting to one side and then the drive and/or idle tumbler catches the drive dog on one pad as it starts or tries to enter the drive tumbler.

Today I am going to make the lower and upper rollers and see if that helps keep things lined up.

Also going to try standard pulleys and O Rings instead of sprockets. I can make them easily, they will provide a lot of "give" if something binds and I have the parts on hand. Hope to still use sprockets and chain at some point.

[Rvjimd]

Added a solid lower guide to test my suspicion about keeping everything lined up helping with operation. With the guide I was able to easily identify two pads that had drive dogs a bit off center. I replace those and tried a motion test with the drill motor.

Trouble going into reverse from this direction with no guide or rollers on the top, the pads want to shift to one side just enough to try and ride up on the tumbler.

http://youtu.be/rLnZibly4JY

Jim

[JAMMER]

Hello Jim you have a great start there keep it up. Ed

[Jared]

How about this for tensioner screws, Jim?
https://www.microfasteners.com/home.php?cat=576

With a hex head screw you could make a wrench to reach in from the side and avoid drilling holes in those nice pads.

[Rvjimd]

Reg, yea I hadn't even thought about a hex (probably just cause I don't have anything that small). That would probably look good there to boot! ;)

Jim

[Rvjimd]

Oops, thanks for the tip on hex hardware Jared. It must have been past my bedtime when I responded last night.:p

Jim

[modelman]

Jim-that is probably a better system for tension adjustment but as I said before, once you get the tension set correctly I don't think you will need to adjust it again. Keep working!!

[Rvjimd]

I had to stop and pose the crawler for a motivation photo, it seems like there is a never ending list of parts to be made, re-made, and fine tuned, and I still feel like I don't get too far for all the time I spend on it. :p this sort of view helps me keep going!

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG1009_zpsccjz2zbd.jpg

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG1008_zpsssrldk20.jpg

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG1007_zpsar2kwn78.jpg

Still to do -

slip ring and mount the rest of the ring gear and spacer
Pick and mount motors, make pulleys for the drive tumblers
And at least a dozen other things I have forgot about...:thinking:

Jim

[Car5858]

Great inspiration:cool: :)

[modelman]

Jim-here is the video of my shovel tracks working that you ask for-
http://i305.photobucket.com/albums/nn216/modelman/th_100_0953.mp4 (http://i305.photobucket.com/albums/nn216/modelman/100_0953.mp4)
This was after many changes I had to make to the pads and the tumblers.

[Rvjimd]

Tom,

Thanks for the video! Those work good and it ALL looks good too! After seeing your mold the other day it makes me want to try again with a narrower pad front to back and something different than my riveted drive dogs. I'll keep plugging away at what I have and learning what to do different on the next one:rolleyes:

Jim

[modelman]

Your welcome jim-your project is looking good. Looking ahead,narrower pads will probably work better. It will take more of them but they will make the circle easier. From what I see on machines today the pads are getting more narrow and they probably work better than the older machines. Did you decide against the button-head screws holding the pads together?

[Rvjimd]

Ya, the button head was a bit larger than the 1/8" pad and I didn't think it looked as good as the cap screw. I might put a bunch of them on and look again, but I think I ordered them a bit too long which won't work...:o

Jim

[Rvjimd]

Motor mount. About one time in ten or twenty I feel like I machine something and it turns out like I planned. I had some 1-1/2" 1/4" wall aluminum tubing, cut off a chunk, had to square it up cause my bandsaw decided it should start out wedge shaped.:p then I cut it in half, drilled and tapped for 4-40 screws. I'm not sure how this mount and drive arrangement is going to work out? I don't like how it is going to force me to raise the ring gear and everything else up higher than I planned. We will just have to see how it goes.:rolleyes:

I thought about using the threaded mount holes in the end bell of the motor, but I didn't like that due to tight tolerance where if I mis drilled a hole it was no way going to line up good.

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG1011_zpsbb8rembs.jpg

No, make a small and large pulley for an O ring to drive the tumbler.

Jim

[Rvjimd]

Pulleys and O ring. Need to finish the rollers now...

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG1012_zpsxbaithqi.jpg

Jim

[9W Monighan]

Hey Jim, Have you thought about powering the carbody through the center pin like the 1:1 machine? One motor bevel gear then make sliding jaw clutches to engage each track disengaged with a servo for steering.

[Rvjimd]

Steve, that sounds interesting, probably beyond my machining abilities, but interesting! I will have to find some pictures and drawings of that, I'm not sure I know exactly how it looks?

Jim

[9W Monighan]

Study my drawings I posted on the 25B build.

[modelman]

I see you are making progress jim-You said you would have to raise the swing gear over this motor. Is that going to cause any problems? I like 9W's idea on the movements but that would require a lot of technical machining and this is a really small model. Are you up for that challenge? :eek: I probably could not do that.

[Rvjimd]

Tom,

I made a round 1/4" plate to raise the swing gear just to get it up off the deck so the pinion had a bit of clearance. So, I think I can flatten the top of the motor clamp a bit and then I will make some braces that screw to the flat top frame to hold it all together, since the motors basically split the flat part in two parts. As long as it doesn't look like the body sits up too high I should be okay. It should actually improve the digging geometry for a drag bucket.

I would love to do the central power scheme but you are right. It is just really small to make all that work. I am going to proceed with the current motor placement and try to work out the pads function . Still messing with tumblers and alignment issues.

Jim

[modelman]

Jim-seems like you have a good plan. Will the O-rings for the drive belt have enough grip? Aren't those track pads fun!!! :D

[Rvjimd]

Tom,

If I don't know for sure on the O rings. My master plan is simple pulleys and O rings just until I get the pads working the way they should/need to. Then convert from O rings to that small plastick Chain and sprockets. I have some steel roller chain but I think it is too big to look or function well and I think plastic would probably work okay as long as the pads and tumblers are working right.

I need to put the RT back on the mill and make some more tumblers. I don't have a combination that works to my satisfaction yet.:o

Jim

[Rvjimd]

Got the top plate split so I could mount both motors. Ended up making new smaller drive pulleys just cause they would fit better and the speed reduction will be good. Still haven't made a decision on how to make rollers or solid rails in order to help maintain alignment. I should get that started now, gona want to see if this thing is going to move on its own!:p

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG1015_zpswrkpn1ph.jpg

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG1016_zpssjsynt6o.jpg

Jim

[Izzy]

That's lookin really beefy and tough. Kool

[Trucker_Jo]

Wow, that looks really good! Love the old school tracks.

[speedy8305]

great job you have done there so far it is coming along quiet well keep up the good work

[Rvjimd]

Thanks for the nice comments guys!

I started mounting the swing gear on top of the frame. With any luck I will have the crane in place and digging dirt by the end of the weekend.

I need to make and mount the round adapter bushing to the inside of the cab. Pictures in a few hours...

Oh, and I ordered some plastic chain, sprockets, bevel gears and stuff from servo city. I think I am going to need to learn how to make two small sprockets.

Jim

[tracksntreadslou]

looking good Jim ..quite a challenge and not your typical build ...your working through some pretty difficult challenges ..If you have a rotory table / Drill press you should be able to make your own spockets ..I did make my own for the Dozer.. A bit of math and you probably knew already though ...your circumference should match your pitch ..10 tooth x .25 pitch = 2.5 circumference
so diameter would be 2.5 divided 3.14 = .796 .Thats where you would drill your 10 holes
Overall sproket diameter would be bigger ..dont remember how many turns it took for one rotation of the RT but im sure you would figure it out from there..I did have to touch up a few of the teeth with a dremel though
I started out with with a 3x3 square .2 thick aluminum plate ..scroled the diameter of the circumference ..drilled the center and used a bolt and nut through the center hole to mount in the RT .Once the holes were drilled i cut out the sprockets with a band saw ..hope this helps you out a little

[Rvjimd]

Lou,

Thanks for the tips. My parts might be here Monday so I can see how stuff fits. If I'm lucky I might be able to use what I ordered.:p

Got a bit more done today. Actually took some video trying to dig wet sand but it sticks in the bucket so bad it wasn't worth posting. Besides, I don't have the tracks moving yet anyhow:o I just wanted to see how it looked digging, sitting on the new undercarriage!:D

These are shots of the threaded bushing that inserts into the hole in the cab. The hollow stud is an old 1/2-13 bolt that I bored to run the wires from the slip ring.

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG1020_zpsptayivpt.jpg

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG1019_zpsw9lpn7de.jpg

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG1018_zpsk7lmpd8k.jpg

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG1017_zpsosmcdepz.jpg

Maybe I can dry out some sand Sunday and post a digging video...

Jim

[Rvjimd]

Some more pics...

It looks SO much better all rigged with a bucket on it!:D

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG1021_zpsoxh6qdup.jpg

I took one motor apart to match drill mounting holes (which I ended up NOT using:o) this is a "how the heck does this sucker go back together" photo.:rolleyes:

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG1010_zpsonwxkur4.jpg

This shot is too close to really see the setup. This is where I clamped the cab down to the mill table and used a fly cutter to enlarge the pivot hole.

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG0999_zpsattwns24.jpg

Jim

[modelman]

Your making good progress jim. You should be moving dirt soon. You may not be thinking about this now but are you planning to R/C the truck that this dragline goes on? That's a good idea to still use the truck and the crawlers.

[Rvjimd]

Tom,

My original plan was to motorized the truck and swap the crane from one to the other. I had to cut the big hole for the crawler slew but I can mod the truck bed to make that work. I actually bought a second entire truck crane just like the first so I don't know what I might do with them both now...

Jim

[robcakes]

fantastic job

[Jared]

That bucket looks great!. Well, so does everything else.

[Rvjimd]

My parts came in yesterday and it looks like the sprockets are going to fit really good! :p the plasticky "roller" chain is sort of cool, it comes in a bag and you snap each link together. It will make things much easier than the O ring setup since I can break it at any link to take it off and on. I ordered HiTec spline hub sprockets so I made new hubs and tapped them for mounting to the sprocket and put a set screw in the hub.

I STILL have to make rollers! :rolleyes: but, this baby is really close to moving to the job site!:cool:

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG1023_zpshdtvdlr4.jpg

Jim

[modelman]

Looking good jim-You are really close to making a move across the floor. This is when it gets exciting!! Did you find a slip ring that will fit this model?

[Wiskybilt]

It's been a while since I was on. You are really getting it to all come together nicely. Thanks for sharing all the pics and your build with the rest of us.

[Rvjimd]

ITS ALIVE, :p enjoy the mistakes the operator makes, you can tell it has been several
months since I ran this thing ;)

http://youtu.be/MBk1NOU6REk

http://youtu.be/pKyItv_0cYU

Thanks to everyone for the comments, helps me keep going!

Now, I wonder what my subconscious aversion is to making the upper and lower rollers? I know it will work better once I get those done. I'm sure that is the first thing the shop manager is going to throw at me when I show up tomorrow!:rolleyes:

Jim

[Rakthi]

A fricken brilliant job you did on that little machine!

Congratulations are in order :)

Stephan

[Jared]

That's great, Jim! But I don't think that driver was very happy with the way you treated his truck:D It walks just like the Link Belt LS-52 I've been around a little. Tracks snap, pop and squeak just like it. Rollers will make it smooth as long as they stick down lower than the tumblers/idlers. You don't want the bottoms of the tumblers and idlers at the same height as the bottoms of the rollers or it will still hop. When the pad transitions from flat on the ground to the tumbler, the leading edge goes up but the trailing edge has to go down since it cannot conform to the radius of the tumbler. If you see any steel tracked machine that is hopping along, it means the undercarriage or at least the bottom rollers are worn out. Sucks when you are trying to hold a grade with a dozer or walk it any distance on hard ground.

Did you have to do much monkeying with those drive chains to get the proper amount of slack? Where'd ya get 'em at? Looks like the direction I might want to go.

I see one more item to add to the list: a fairlead to keep the drag cable away from the tracks.

[Rvjimd]

Thanks guys!

Ya, Jared, you got it right on the truck driver.:p I was cracking up when I watched the video the first time. It was like I was sleeping as I swung around and clanged into his truck. :p

If I had a fairlead on the drag rope it wouldn't try to boom up when the rope get stuck on the track. My current rope path goes around two pulleys low on the boom so when it pulls hard it booms up:o

The chain is from servo city. It is .25" plastic and I used their plastic sprockets. It comes in a little bag with all the parts loose and you have to snap the links together. I got lucky with the slack, I didn't make any adjustment allowance in the drive tumbler or motor mount. I could put on a smaller tumbler sprocket if needed but I was able to pull it together with needle foreseps and pop the links together. On one side I removed the pin from the tumbler and assembled the chain and then slid the pin in place. I already had some standard steel chain bit the plastic stuff is going to work good and is munched easier to work with.

Jim

[9W Monighan]

Looking good Jim. We could bind that up to my controls next month.
Anyhow, Try changing the host chain length and dump cable length. I noticed the drag chains not pulling like they should because of the dump rope. Just some minor experimenting you will be able to dial it in I'm sure.
There seems to be an art to getting a bucket to work correctly as I had found out with mine.
Next project would be to build a fairlead to get the drag rope out away from the track.

[Rvjimd]

Some photos of the chain drive setup...

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG1024_zpsdnqzx1dy.jpg

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG1025_zpsahwb6nbs.jpg

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG1026_zpsdiw5ok9a.jpg

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG1027_zpsujmfwxvc.jpg

Working on upper and lower rollers today:bounce:

Jim

[modelman]

Nice work jim-this is the pay-off for all that work. The operator does look a bit rusty but I'm sure this will work it's self out :D. How many channels are you running? You have a lot going on there.

[Rvjimd]

Steve, ya a fair lead would be good. I was trying to dig wet packed sand the other day and my attach points on the drag rope at the bucket are too high and cause it to tip the aft end of the bucket up. I plan to make some new brackets so I can move the attach point up or down for different soil types. I haven't really tried to tune this setup since I got it running last fall. I have the airplane instrument panel ripped apart for an upgrade so it looks like I will be driving again this year. I should find a topper for the truck so I don't have to sleep on the ground this year ;) don't think Jennifer is coming with me this year. Going to be a long drive doing it all myself :(

Tom, i thought i had the bucket a bit higher on a few swings:rolleyes:. As soon as i sat down i knew it was going to be a crash fest.

I am running 6 channels. The stupid motor controller is fussy so I have to use a separate BEC for the radio and servos, and that means every one of the seven sockets on the RX has a plug in it! They put the pins so close on the RX that the plugs hardly fit.:p

Jim

[Rvjimd]

I should have just copied this picture from your thread Jared! :p

Jig to make the roller axel shafts. I decided to do it just like you did with a flat on each end of the shaft and drill them and tap holes in the side rails.

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG1028_zps1llhpkvq.jpg

Jim

[9W Monighan]

Those drive chains fit very nicely under there.

[Rvjimd]

Steve, ya I got lucky! They have a smaller plastic chain but I didn't think it would hold up and it might have looked too small? I think this stuff turned out just about right.

Here is a picture that explains how I get any work accomplished in the shop AND read the forum and post updates all the time. The iPad is on the wall right above the band saw. ;)

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG1029_zpsvhgmtb5u.jpg

Jim

[modelman]

Jim-I know what you mean about the rec.. The last one I hooked up was so small I almost couldn't deal with it. I think you made a good choice on the roller pins. It may take some time to make the jig but then it should go well and I think you will like the results.

[Rvjimd]

Rollers and pins, rollers and pins...and I'm only about halfway done:rolleyes:

Need to make 5 more of these and then match drill and tap the holes. And that is only the bottom, five each side:p

I think I will/can do 2 each on the top.

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG1030_zps01amwjry.jpg

Another one of those things that I think, "well, that shouldn't take too long" and then I spend all day doing it:D

Jim

[9W Monighan]

:D:D:D Nice

[Rvjimd]

Ha! I'm kicking some pins, spacer and roller butt now! :p

http://i1291.photobucket.com/albums/b554/Slotcarjim/IMAG1031_zpscgh2rw46.jpg

Going to be five on the bottom and probably two on the top. I tried it last night with just the two outboard rollers on each side and it works SO much better with rollers!:cool: it almost like having bluetooth on this sucker!:D

Jim

[Rvjimd]

I got the idlers rollers all finished and installed!:cool:

http://youtu.be/fiCI-9QpdCQ

Makes me wish I had a truck and an low boy to haul it on...

Jim

[modelman]

Jim-that seems to work really good!! Your suspension looks a bit stiff to me though. :D :D Just my opinion but you have gone this far, I say put a 3rd. roller on the top just for looks if nothing else. The bottom looks much better to me but the top needs more. Great job either way!!Maybe you are tired of making little parts.

[Rvjimd]

Tom,

I was not looking forward to today's thanks of making eight more roller,pin, spacers sets and then mounting them. But, today I tried the pneumatic drill for the small #50 drill for the mounting holes in the frame rails and it worked really good. So, I might add more. My big problem is the placement of them and interference from the rest of the frame.

Did you mean the tension looked too tight or something else on "suspension"?

I am elated at how well it worked out! I have been running it a lot today and can't wait to see how it "breaks in" and what trouble spots pop up.

Jim

[RCKiwi]

Awesome result on the tracks - simply, very realistic and they work a treat, with great scale operation. The chain drive was a good move - I think the o-ring drive set up would not have been able to transmit the sort of torque your unique track gear requires. I watched the digging vid too and was impressed - I wish I could find these sort of old retired workhorses over here in NZ to convert like this.
Nicely done I reckon and such a marvelous result without all the flashy gear.
Top marks!
Glenn

[Rvjimd]

Glenn,

Thank you very much! It is actually quite fun to dig and even more so now with the undercarriage !:D

The pulley and O rings was just my lazy initial test to see if it was actually gong to be a workable system, I already had the .25" steel roller chain, but the new plastic stuff became available and it is very easy to work with and seems up to the task. I also really like the fact that it should be a "weak" link in the system I case of over stress.

Jim

[modelman]

Jim-I was just teasing you. A lot of people on here like to brag about how much suspension travel they have in there models and watching you crawl over that air hose made me see just how realistic this model worked. Watching it go over the hose and the blocks looks just like a real shovel moving. I know the rollers are your choice but this is a great model and you should be proud.

[Rvjimd]

Tom,

Thanks for all your tips along the way, that helped me keep going!

I looked at the top rollers again and I think you are right, it sort of looks like it is missing something. The track pads are actually resting on the sprockets and chain at the top center. I'll ponder it a do something.;)

Jim,

[Jared]

I was kinda mesmerized watching those tracks roll over the blocks and hose. I think the chain is pretty realistic. Great job, Jim.

[Rvjimd]

Jared,

I should give you a big Thank-You also! I couldn't have done it without all the good information from your thread!;)

Thanks to Steve for posting all the drawings of the BE In Jared's thread! I have some of them printed out and hanging
over the bench in the shop!;)

And, here is a link to 20 minutes of moving sand at the loading dock.

http://youtu.be/J_7SKGJWoV0

Jim

[modelman]

Nice video jim-looks like the operator is getting back in the groove. You may have the drag chains mounted too high on the bucket. I think that is why it wants to tip over forward. Just some minor tweaks though. Looks like you are enjoying yourself and the tracks seem to be working perfect.

[Rvjimd]

I painted the undercarriage and made some other adjustments. Also put in a dirt ramp on the south end of the loading dock for the crane and trucks to get up and down.

http://youtu.be/tQO3R-t4RXk

Jim

[kerst]

I painted the undercarriage and made some other adjustments. Also put in a dirt ramp on the south end of the loading dock for the crane and trucks to get up and down.

http://youtu.be/tQO3R-t4RXk

Jim

Very nice!

Kerst

[Rvjimd]

Kerst, thanks!

I ran the poor thing in the dirt and spun a set screw on one motor, so into the shop. Cleaned a bit and put a new set screw in. Then I took it back to the sand pile and it had a nice squeak and I hope I figured out my low audio volume so I recorded another short video. The squeak is classic! :p

http://youtu.be/wgfCpIFZDwE

Jim

[modelman]

Looking better every day jim-That is a steep hill but your drive motors seem to have plenty of power. The bucket is working good also. Did you make a change or just better digging conditions. I wasn't expecting that ending. What a shock!!!!! :eek: The operator didn't have time to jump out so I guess a change of clothes is in order for him.:lol: I like the squeak also.

[Rvjimd]

Made a new video today. The sand is really wet and a bit tough and sticks in the bucket a little. Toward the end I try to move but I had some sand jamming things up...

http://youtu.be/f4G3C7oiO1k

Jim

[modelman]

Looks like some tough digging jim but the machine handled it really good. The model looks to be balanced well, do you have any ballast in the back end.

[Rvjimd]

Tom,

Ya, there are two chunks of lead in the back along with two 3S lipo batteries. With the sand wet you can see the weight shift as I lift a full bucket.

Jim

[Rvjimd]

for some reason BoobTube duplicated my cab view video, so naturally when I deleted the second one that indicated they had trouble uploading, they also deleted the primary video. So, I uploaded again.

If an Admin can/or would like to edit the post with that old link and use this new one, and delete this post that would be good, or not...

https://youtu.be/N-ctlSUP2lM

Jim

[9W Monighan]

That is working beautifully. Now you can stop here on your way East and help me work on my control panel:D.

[Rvjimd]

Steve, are you ready for next week? I think I got the wife convinced to come out with me again this year. It is about 12 hrs of driving and I wasn't looking forward to that on my own. See you in a week, we are planning to get there late afternoon Thursday.

Jim

[9W Monighan]

I hope I'm ready. Still painting some stuff. Stop by here on your way through. PM me for contact info.

[TylerDSAudi]

Build is coming along just great! Really nice work on those tinny rollers and track pads! Love the old shovel crawler system look!

[Rvjimd]

I put new line on the clamshell bucket and tried it out moving some concrete blocks.

http://youtu.be/cwm3Fu8yRgE

Jim

[Rakthi]

Hi Jim, nice video! Love the clamshell bucket!

Stephan

[Rvjimd]

Stephan,

Thanks! Even though the drag bucket seem so much more efficient for moving material it is a lot of fun doing "heavy" lifts with the clam bucket. It was interesting to watch the crane tip forward on the tumblers at the end of the undercarriage since I was not blocking it as it should have been for a heavy lift. :p

Jim

[modelman]

Nice video jim-that operator is getting good!!!! :lol: I personally would like to see a few minutes of the clamshell working at actual speed. Did you not make it to Brownsville?

[RCKiwi]

....... I personally would like to see a few minutes of the clamshell working at actual speed.......

Me too! Lookin real good I reckon....:cool:

[Rvjimd]

Thanks for the comments guys!

Tom, I am pretty bummed out about NOT making it out to Brownsville. It was going to be the third year for me and the FIRST time I showed up with a descent machine to move some material.

I need to think about a nice scenario for the clamshell video...

Jim

[Rvjimd]

Tom,

Here is a bit of real time video of the clam loading some concrete blocks into a hopper barge at the north sea wall. I am going to try and find some material that loads well and shoot another video of loose material. The sand was a bit wet tonight and the clam is real tricky on loose material. I have tossed around the idea of making a new clamshell, making it just a bit narrower and maybe a bigger mouth and taller for more leverage in the close.

https://youtu.be/CfcPLkml37A

Jim

[modelman]

Thanks jim-interesting video. The blocks looked like they were almost too heavy for the clam but you got it done. Nice operator work! Smooth and steady is always the best. Personally I like the drag bucket for moving dirt but I guess it depends on the application. I have watched some real clan shells working under water and they seem to do a good job. It seems like most model clamshells are too lite-weight to be efficient when digging but maybe you can work something out. Also I saw a goldfish streak thru the picture a few times. Must have been doing his morning sprints. As fast as he was going I was surprised there wasn't a roostertail coming up behind him :D.

[Rvjimd]

Tom,

Ya, those blocks are pretty much the max load for the thing.

Jim

[Rvjimd]

I had a few questions about the boom and clamshell bucket and made a video trying to explain a few details. Not sure how well I did at that goal, but here is the video link anyway...

http://youtu.be/A4jtn-lO_qU

Jim

[modelman]

Good to see you working on a dragline again jim-I know nothing about the clamshells except most of the models I have seen do not work very well. The weight idea is probably good. I like your technique on cutting the aluminum. Seems to work good although me being a wood worker I cringe when I see that. :eek: My dad used to take pride in how good of an edge he could put on a wood chisel (and his pocket knife) so I'm sure he would not like this but I say what ever works. Is there any way to put a release line on the clam bucket? I think you said it had to go all the way to the top of the boom before releasing. Is that right?

[Rvjimd]

Tom,

The brass clam that I built DOES have a closer line and a hoist line just like a full scale bucket. What you heard me say about going all the way to the boom tip was the old black bucket that came as original on the toy.

Jim