All-Terrain Tractor "Muskrat"

Hi folks!  Its been awhile since I've been on here and I'm loving all the cool new builds on here!  Well anyways ever since my half-track I decided to keep to tracks, so in essence I'm building a fully tracked vehicle.  So I started with a Murray garden tractor took only the transaxle and engine from it and is based on a completely homemade undercarriage and running gear.  I realize its not a "true" ATLT, but I've done that so many times, it was time for something new.  Basically I am using the donated power train components from a GT and using them for my homemade chassis.  Anyways the suspension is based on a Bombardier J5 skidder vehicle, this comprises of a walking beam and a front sprung trailing arm unit.  The wheels are 4 ply T115/70D14 TempaSpare tires that you can get real cheap at the scrapper and are all on tapered roller bearings.  The tub is welded 14 ga steel, it is a little flexible I noticed, especially torsionally, so I hope to reinforce it later on.  The engine is a 16 horse Briggs opposed twin and the transaxle is a Peerless 820-018.  Now since I've rarely over driven a transaxle, what is a good safe limit of imput RPM while still keeping a modest lifespan?  I wanted to over drive 1/3:1 or have a 12" pulley on the engine and a 4" pulley on the trans.  Does anyone have experience with over high overdrives on these or am I asking for trouble?  Here are some pictures of my current progress on the undercarriage .


^Mockup

^How it is presently

^Front sprung trailing arm, very nice and squishy

^Walking beam, track tensioning device can be seen

^I can't wait to take it off-roading!!!!  I'm going to have to leave on a cliff hanger as I am in Michigan on an internship and I won't be back in Iowa till classes start at the end of summer, until then I'll be entertained by others builds. 

A TANK! ... you beat me to that build my friend, but I can't wait to see what yours turns out like... kick-ass!

** Edit - have you thought about making a compressed-air 'gun' with some sort of pop-off valve, to create a nice loud BOOM?

Way cool!

i have a hydro its about 2-1 ratio. 7 on my engine and a 3 on the tranny. no problems yet. i had it the same way on another mower 7 and a 4 and hit 30 without problems

This evening I had some free time so I decided to start making the drive sprockets.  This is how I started making the teeth of the sprocket.

The teeth are made of 1/8" X 2" flat stock cut at a 15 degree miter.

I made a die and stamp to bend the flat stock at a slight radius.

A couple of thwacks with the minisledge produced a nice convex face.

I had my workout for the day (and several callouses on my hand).
 
Put them in a welding jig and welded them puppies up!

Finished tooth, dimensions came out perfectly where I wanted them 1.75" wide and 1.375" in height .

Finished 12 today before I called it quits.  This is enough for one sprocket, I will finish the rest tomorrow and grind away some of the welds.  So far so good .

hey man i moved the thread to here because, even tho it is all terrain, there isn't much tractor left, im very interested to see how this comes out man

prometheusEDI wrote:

A TANK! ... you beat me to that build my friend, but I can't wait to see what yours turns out like... kick-ass!

How did you see through my disguise?  For now lets just call it a crawler tractor with armor.  I would like to skid timber with this after I finish .

crazykid1994 wrote:

i have a hydro its about 2-1 ratio. 7 on my engine and a 3 on the tranny. no problems yet. i had it the same way on another mower 7 and a 4 and hit 30 without problems

Awesome, thanks for the info.  I put about 4 ounces of STP Oil Treatment into the 820 to loosen up the bentonite grease.  I guess I will stick with the 3:1 ratio, I just hate that gear whine of those straight cut spur gears at high rpm .

richie thomas wrote:

hey man i moved the thread to here because, even tho it is all terrain, there isn't much tractor left, im very interested to see how this comes out man

Good deal.
Also a correction on the teeth, they use 1/8"x1.5" flat stock NOT 1x2 flat.  Whoops

I wanna see this get done. If you do a cab on it it would make a great paintball machine. >

Doug Fackler wrote:

I wanna see this get done. If you do a cab on it it would make a great paintball machine. >

shouldn't be to hard to do, but think it would work better if it was a removable top half,

richie thomas wrote:

Doug Fackler wrote:

I wanna see this get done. If you do a cab on it it would make a great paintball machine. >

shouldn't be to hard to do, but  think it would work better if it was a removable top half,

It could be removable, it doesnt have to be solid. Tube steel and field netting will work.

Now THAT is gonna be cool!!! What do you plan to use for tracks, snowmobile stuff?

Also- with some careful design, you've got a damned good start to an amphibious vehicle. Have you given any thought to that?

Doc Sprocket wrote:

Now THAT is gonna be cool!!! What do you plan to use for tracks, snowmobile stuff?

Also- with some careful design, you've got a damned good start to an amphibious vehicle. Have you given any thought to that?

At first I was thinking snowmobile tracks, but I decided instead to build my own tracks for traction and strength reasons.  Last week I too had thought if it could be amphibious.  I did some calcs and with the predicted weight I would have to widen the tub by 9" just to get enough buoyancy, so I decided to keep it as.  Plus here in the glacial till of Iowa, I hardly encounter bodies of water where I will be going.  Now if I was in the Canadian shield area around upper Minnesota and Manitoba with all the kettle lakes and rivers, oh yeah an amphibian definitely would be the way to go.  My next project I do hope will be an amphibian though.

All 24 finished teeth, now I have to wait for $$$ to buy steel and tire rims. 

Just make a watertight cab and a snorkel kit and youll be fine lol.

That would be pretty awesome too.

than again it depends on tire size and the ratio inside the hydro

I've had thoughts about amphibious builds. One way to ensure watertightness (and TOTALLY foolproof) is to simply NOT penetrate the hull with anything. You could mount the tranny well above the waterline, and extend the shafts outboard of the hull. From there, it's chain and sprockets. The downside is that all that running gear will be submerged every time you're in water, so maintenance is a must...

This evening I continued work on the sprockets.  

First I cut down the flanges of the rims to the proper O.D. of 14" using an angle grinder.

The rolling surface consists of 1/8"x5" flat stock that was first clamped and inch by inch bent around and welded to the rim.

Further bending, it was quite easier than I anticipated to bend.

Cut off extra.

Completed wheel, diameter came out very concentric with only a few areas coming off 1/32". 

Welded teeth to appropriate pitch, unfortunately the measuring tool I was using only goes a 1/16th" and I had 1/8" of misalignment between the last set of teeth.  I only tack welded them so I will redo them once I obtain dial calipers.  Plus not to mention I was in a rush to see the final result.  Ah well.

Those 1/64" of inaccuracy really add up with 12 teeth!

Nice I might have to make some as never flat tires.

Doc Sprocket wrote:

I've had thoughts about amphibious builds. One way to ensure watertightness (and TOTALLY foolproof) is to simply NOT penetrate the hull with anything. You could mount the tranny well above the waterline, and extend the shafts outboard of the hull. From there, it's chain and sprockets. The downside is that all that running gear will be submerged every time you're in water, so maintenance is a must...

Aye.  Several months ago I started on a concept of a tracked AATV, I really ended up liking the design and concept.  Unfortunately I am at that stage in life where crossroads are closing, so the resources and logistics for such a project are nonexistent.  Once I settle down and acclimate to the "real world", I hope to start on it.  For now this armored crawler will be a good prototype and a learning experience .  Here is the AATV on paper...

I did a cost analysis and came out conservatively at $6,000 USD (at present steel prices), still cheaper than a newer used Argo with tracks .

Looks great! Even plain you will still end up with some insane traction.

Very very cool fabrication. Very clean and well made. Awesome.

Work continues on the crawler.  This weekend I am back in Iowa and finished the final drive/steering unit aka a super shortened Chevy 12 bolt axle.  The half shaft outboard holes were also drilled in the tub.  I have a plan for these half shafts utilizing the 1" drive axles of a old Roper Rally transaxle.  I do hope they are strong enough, but for the most part, they will only be undergoing torsional stresses so we will see.  I will also be removing the current angle to tube mounts to something more nicer.  Until next time...

Wow. That's one of the shortest stortened axle I've seen

this is really cool, very nice fab work, did you get the axles resplined or just weld them?

redlinemotorsportts wrote:

Wow. That's one of the shortest stortened axle I've seen

Haha, it's the shortest it could go.  When I finished it, I had to resist the urge to put it on a garden tractor.

Creepycrawler-  The shafts were just ground to a point and welded with multiple passes.  Good 'nuff for my purposes.  I just wish there was a group like you guys around my college town that romps tractors for fun.