ADT Project

[Vanisle]

I finally started one of my projects, an ADT based loosely on a Cat 350D. I am using 34 rpm / 139 oz-in gear motors from Robotshop and RC4wd MilSpec 2.2 tires.

I decided to make my own rims and hubs (using 2.5 and 1.25 inch aluminum round rod). The motors are longer than I thought so I had to make the rims offset. After much thought, I came up with a plan using a hub with set screw with the main rim bolted to the hub with ten 2-56 stainless hex bolts.

I had a little disagreement with a $20 2-56 drill bit - it wanted to stay in the hub and broke itself off to achieve this wish. I wasn't very happy but rather than go to the effort to get it out, I left one hole as a blank,

This is basically my proof of concept hub/rim and I need to make 5-6 more. Unfortunately, it could be a long time before I get back on this because I have real work to do.

Here are some slef-explanatory photos:

http://i1108.photobucket.com/albums/h404/vanisle11/1Rim.jpg
http://i1108.photobucket.com/albums/h404/vanisle11/2Rim.jpg
http://i1108.photobucket.com/albums/h404/vanisle11/3Rim.jpg
http://i1108.photobucket.com/albums/h404/vanisle11/4Rim.jpg
http://i1108.photobucket.com/albums/h404/vanisle11/5rim.jpg

I have never used a lathe before and had no idea what I was doing. It isn't real pretty but it will work.

By the way, the lathe is for sale or trade in the buy and sell section (because I want a larger one to be able to work quicker).

Richard

[Snochaser]

Frickin' awesome!

I had to order some from Germany since I don't have that option. They look great!. Boy I'd love to buy your lathe you have for sale, but I have other needs at the moment.

[RCLogger]

looks good Richard

Glad to see your project is taking shape. Great idea making the rims and hub combination work with the motor. You will have more than enough power with those motors. I am looking forward to loading it up with dirt..

greg

[Vanisle]

Thanks Snochaser and RCLogger. I thought of buying some rims but did not know what I would need. I also wanted something that looked like it had planetary hubs. The nice thing about having a lathe and milling machine, I can make my own rims for about $4 apiece (and a whole lot of time).

It doesn't show up well in the other photos but the hub fits nicely into a bored out space so there is a lot of metal on metal contact between the hub and rim. I also put a slight indent in the motor shaft so the set screw will be more secure to prevent the hub from both spinning and pulling off the shaft.

The hub I showed is actually the second I did. The first one took two drill bits (broken off in the hub), one centre bit (broken off in the hub), a 1/8 end mill (broken off when I accidentally went the wrong way milling out the bits) and 2 dulled 3/16 end mills (milling out the end mill). I eventually got everything out and filled the holes with JB weld ... but what a pain.

I made a small attempt to get the broken bit out of the second hub but soon gave up and filled the hole with JB weld.

Here are a few more photos:

http://i1108.photobucket.com/albums/h404/vanisle11/6Rim.jpg
http://i1108.photobucket.com/albums/h404/vanisle11/7Rim.jpg
http://i1108.photobucket.com/albums/h404/vanisle11/8Rim.jpg
http://i1108.photobucket.com/albums/h404/vanisle11/9Rim.jpg
http://i1108.photobucket.com/albums/h404/vanisle11/10Rim.jpg

[Lil Giants]

A great start on an interesting project Richard. http://www.scale4x4rc.org/forums/images/smilies/nice.gif

[RCLogger]

Must be time for a update Richard
Are all the rims done ? Its almost time to start sleeping in the shop cause spring is just around the corner. We need that ADT up and running. hahha

Get-at-her
greg

[Vanisle]

Not quite yet. I did get the rest of the rims turned and bored out (on the new lathe) but I stil have to do some milling on them and drill the hubs. I need to order some tubing for the axles and then I'll move on to the frame, etc. Unfortunately, the next 1-2 months are going to be pretty busy for me workwise. I shouldn't be spending any time in the garage ... but it's hard not to.

I've been busy tooling up the new lathe. It never seems to end.

[RCLogger]

Any updates Richard ?

[Vanisle]

Well, umm, no. I have been buying some new machines (sold the old lathe and bandsaw and bought bigger ones), tools (darn Enco and MSC sales) and parts (transmitter, motors, ESC's, valves, etc) ... but no more work has gotten done. I am looking at late april before I have any time to myself. Yah late April looks good unless something comes up.

[russisloud]

thats some very nice work on the rims and hub for a first shot

[Vanisle]

thats some very nice work on the rims and hub for a first shot

Thanks. What I lack in talent I make up for in tooling - I need all the help I can get in making parts. Sometimes it works out, sometimes it's a disaster. It's all fun though.

[Vanisle]

A small update on my slow motion ADT project. I made some axle housings out of aluminum tubing. I had to step the inside to slide in the gear motors for a nice snug fit. I will secure them with a couple of set screws - I wanted to be able to change the motors if needed. I also had to turn down the ends on the outside so the axle housing would fit over the rim.

My lathe DRO made it very easy to duplicate the parts. I also finished off the rims and hubs. Next step is to start the frame.

Here are some photos:

http://i1108.photobucket.com/albums/h404/vanisle11/Axle1.jpg
http://i1108.photobucket.com/albums/h404/vanisle11/Axle3.jpg
http://i1108.photobucket.com/albums/h404/vanisle11/Axle5.jpg
http://i1108.photobucket.com/albums/h404/vanisle11/Axle6.jpg
http://i1108.photobucket.com/albums/h404/vanisle11/Axle7.jpg

Richard

[JensR]

Great work, Richard!
35rpm sounds maybe a bit on the slow side? OTOH, it'll have pulling power to no end! :D

[texken]

Hi Vanisle, Looking good.
JensR do you think this motors might work??
DC Motor: High Torque Mini 12V DC Gear Motor, 50 rpm

[Vanisle]

I don't remember exactly how I decided on this motor but I think I was looking at the speed in RCLogger's ADT and these were pretty close. I plan to run these on 13.2v batteries.

[cbazq271]

watching this closely. Looks great so far

[cbazq271]

If you need a Radio and or esc's, PM

[Vanisle]

If you need a Radio and or esc's, PM

Thanks for the offer. I think I already have everything I need (for this and a couple of other projects) ... but it has been awhile so I don't recall exactly what I had planned. One of the disadvantages of building so slow. Richard

[JensR]

JensR do you think this motors might work??
DC Motor: High Torque Mini 12V DC Gear Motor, 50 rpm

No, these are too small for Richard's large&heavy ADT.

Richard, you may well be right and you have 10% extra speed with 13.2V :)
As you already have the motors, I would suggest to just bolt/tie three or four (or all...) of them onto a wooden board and see how fast they go and decide whether this is acceptable to you.

Just my $0.02, hope you don't mind - for me it's always very annoying to have to change motors and I try to test as much as I can before I commit to a motor and mounting hardware.

Cheers
Jens

[Lil Giants]

35rpm sounds plenty quick for the gh motors' rpm -> what's the diameter of the tire?

What's the wall thickness of the tube to tap threads for the set screws? You gonna drill into the gearhead a bit too?

[Vanisle]

35rpm sounds plenty quick for the gh motors' rpm -> what's the diameter of the tire?


What's the wall thickness of the tube to tap threads for the set screws? You gonna drill into the gearhead a bit too?

Hi Joe,

I am using the RC4WD Mil-Spec ZXL 2.2 tires. The diameter is 5.17" (131mm).

I am going to use some M5 set screws and I do plan to drill slightly into the gearhead casing. The tubing is approx 2.43 mm thick where I will drill through (just past where it steps up on the outside). The motors fit in the tubing without any slop so the set screws are to hold it in place and stop the motors from rotating or coming out. I also plan to use some liquid gasket seal, something that isn't permanent but that will give it some friction to help stop the motor from turning in the tubing.

Richard

[JensR]

So, I did a bit of research now ;)

First I found: I couldn't find a "Cat 350D" ADT, but there is a John Deere 350D.
http://www.deere.com/wps/dcom/en_US/products/equipment/articulated_dump_trucks/350d_series_ii/350d_series_ii.page

EDIT: Okay, the truck is a Cat D350 or maybe a D350D...
Anyway, both use 26.5R25 tires:
http://www.bridgestone.eu/upload/album/AP_429.pdf

These have an outer diameter of 1736mm.
http://www.bridgestone.eu/upload/album/AP_429.pdf
The RC4WD tires have a diameter of 131mm.
->Scale 1736/131 = 1:13.2

The circumference of the original tire is 5.45m
This means that from the John Deere pdf (I didn't find a D350D one but from http://www.ritchiespecs.com/specification?type=&category=Articulated+Dump+Truck&make=Caterpillar&model=D350D&modelid=91901 we can guess that the D350D as a speed like the Volvo 350D without its 6th gear) we can convert their speeds to rpm at the wheel:
1st gear = 25rpm (5 mph)
2nd gear = 52rpm (11 mph)
3rd gear = 74rpm (15 mph)
4th gear = 113rpm (23 mph)
5th gear = 144rpm (30 mph)
(6th gear = 165rpm (34 mph) only John Deere)

If you intend to do only (very) short hauls, 35rpm seems maybe acceptable, if the 35rpm of these motors is the load speed. If it's the no-load speed, I think that even then it would be too slow.

Cheers
Jens

[Vanisle]

Wow, that's a lot of work Jens! Yes, it is a D350D not a 350D. If it is too slow, I will change out the motors (which might require re-tubing the axle housing) or perhaps try to make a reverse planetary. Realistically though, I think I will be happy if it ever moves under its own power in my kids' sandbox (which happens to be 14'x24').

Richard

[JensR]

Hi Richard!

That's a big sandbox! Would love to have one that size to play in =)
But I agree, for that size, a slow but torquey motor is maybe not such a bad idea.
And as I said, you could always mount some motors to a wooden plate and see how it goes in the sandbox :)

Cheers
Jens