another 'Tamiya' dig unit

[BigSki]

I first saw one of these on a club members truck last summer. Metal Masher is his name on here, he makes the realistic body panels for the 'Yota trucks. After asking him a bunch of questions, then seeing his build thread on here ( 'digging outside of the box' is the title of it), I wanted to build one for myself but I wasn't sure if I had the time.

I purchased a DNA dig last month only to have so many issues with it I returned it and got a refund. That was the motivation for my 'Tamiya' dig unit. I call it a Tamiya dig because all of the gears come from an old 3 speed Brusier tranny.

I didn't take any fabrication pics because this was an on going project, some of it involved 'utilizing' equipment from my job. Anyway, here are a few pics of the final product. I've only bench tested it so far, but it works flawlessly. I hope to have the crawler moving under it's own power next week.

This is the neutral position


this is the 4wd position



this is the dig position. this gear is bolted to the bracket, so it can't move. the middle gear is splined to the output shaft and passes through the dig gear, supporting the shaft. The front of the shaft is supported by the pinion gear, sort of like a pilot bushing. The shift rod bushing is a simple press fit drill bushing and I used 1/8" drill rod for the shift rod. The whole unit is simple and strong, hopefully it will prove to be reliable. I still plan on closing up the side with thin, clear abs plastic to keep dirt out of the gears.


you can see the 2-56 bolts that hold the rear dig gear to the bulkhead. I messed up a bit while caluclating the bolt hole locations and I didn't catch it until it was too late. Oh well, I never claimed it was perfect.....

[fordmike65]

I like it. I'll be checking in again soon.Hope it works out the way you planned

[Aussie Nerd]

Sorry for digging up an old thread but is this the shaft with the center gear? Possible shaft And if so what is the 'lock gear'? Is it the 18t idler out of the bruiser transmission? Oh and how many tooth is your pinion to the outdrive?

Thanks
Kieren

[BigSki]

Aussie Nerd,

no problem with digging up the old thread, I'm glad that someone can use the infomation. The gear in your link would work, you will just have to cut the shaft down to the correct length and make a flat spot on the end of the shaft so the set screw for the driveshaft yoke has something to tighten against.

The 'dig' gear is one of the gears from the Brusier tranny. I used the narrowest gear that I could find. The gear on the outdrive is a Robinson Racing 18T pinion gear, .8 MOD w/ a 5mm bore. The .8 MOD gear cut is close enough to a 32P gear cut so that it works really well w/ the shift collor.

This home brewed dig unit has been absolutely flawless! I ran a 500 Cobalt motor through it, a 10T Puller motor and the 35T Torque Master. It has never gotten jammed or bound up, it will shift while holding the rig on a hill and it's quiet, it doesn't make a single noise.

[Aussie Nerd]

Thanks, for your info Might have to order up some parts and start making the dig.

Kieren

[Sharkey]

thats a great dig, i like the way its built. gives me some ideas for a home brewed dig, however i need so find some parts thats arent quite so rare like you used.

[BigSki]

Originally Posted by Sharkey

thats a great dig, i like the way its built. gives me some ideas for a home brewed dig, however i need so find some parts thats arent quite so rare like you used.

check out the R2 rebuild kits from RC4WD, they use some of the same kind of gears. I just used the Bruiser tranny parts because I had one on hand.

I want to build another one, using sandwiched plates instead of a milled housing, just to show how easy these things are to build. The hardest part for me was getting the correct amount of servo throw to operate the shift rod. I ended up making a super short servo horn and a simple linkage.

I'll get some pics of the completed dig unit and post them up. The best feature about this whole dig unit is that the driveshaft doesn't move in and out while the dig is being engaged.