Mini bulldozer with mini backhoe: Broken bits and backyard recovery

[dremu]

The treads on the track plates are 1/2" square bar, of which we had to cut a metric assload in two different lengths. The kid did one set on the bandsaw and I chunked out the other on the chopsaw.

The net result, our prototype track plate:

Can't really see, but there's a plate underneath that welds to the chains (only one shown)

Found a place on Ebay that sells grade 8 hardware by the 100, gotta love USPS Flat Rate boxes. Nearly 300 bolts and nylocks for the 140 track plates which turn into 70 tracks.

For once I was thankful for my Trader Joe's cookie habit -- I reuse the tubs they come in, very handy for bulk fasteners.

Don't ask me to do the math on holes drilled/cut. I did it once and cried.

 

[dremu]

The inner set of plates are easy, relatively; they just get welded to the chains:

One side gets a long weld, the other has the hole underneath and so gets two short welds. After doing thirty-odd of them, though, you go crazy, and the damn thing is unwieldy and heavy.

That's a coupla like 15' 2x4's sitting on the drums, and as you can see, is also the paint booth.

 

[dremu]

The outer tread plates ("grousers") are more work. And there's seventy of them. I like welding and all, but I got tired of it with these.

One is fun. More is less fun.

Took me like a week, on and off, to do the lot.

But eventually they're all primed and painted, and then of course promptly get covered in dirt.

 

[dremu]

The inner track with the chains also got the paint treatment and then were hung on the machine:

Starting to look like something, finally. I might have even leaned back and sighed and consumed a lemonade at this point. Normal people would have had a beer. Normal people would not build a bulldozer.

Closeup of the chain tensioner:

There's one each inside and outside on each side, four total. Still fine-tuning, but takes a surprising amount of force to keep the tracks tight. (For scale, the threaded rod down the middle is 1/2" and the springs are like 1.5" OD.)

 

[dremu]

These are sort of random pix of detail bits, not in order with the above. The tub spent quite some time in this form as we collected parts and machined and cut and drilled pieces. Turns out that it's easiest to roll it around on the hoist casters

The far back, right side in this pic, is a category 1 three-point hitch. Those tabs I cut myself, and it shows but at least they're welded solidly, IMO.

I'm contemplating a mini hoe that can mount to the hitch, or be removed when not required.

Took some doing, but finally found some 1.5" exhaust pipe to match the diesel, and an expander to stretch it enough to go around the stack (which is actually conduit, but don't tell anybody.)

The exhaust flapper ("rain cap") is actually purpose-made, also from Amazon. I was gonna build one, but they're cheap enough that it's hardly worth my time.

 

[dremu]

And to keep fingers from getting burnt on the exhaust, got me some steel mesh, bent around a pipe

welded in some tiny round rod

and we have a diesel stack

Bit of black high-heat (barbecue) paint, and it looks like it belongs:

 

[kgblazerfive]

Cool, they did make Cat tractors this small

 

[blazinzuk]

Love it. I have multiple plans for home built tractors saved.

 

[cuervo]

A little OT here, did you add the digital readouts to your mini lathe?

 

[The Butcher]

Did your broach come with the round solid stock that is sized to fit inside the drive slugs to make the keyway? I get the idea of how it works; I assume you just make multiple passes taking a little material out for the keyway each pass. How do you adjust the broach to take more material each pass?

Do you have enough Dewalt grinders? I assume each has a different disc on it so you can just grab the next one you need without having to swap discs each time. Awesome!

 

[dremu]

Cool, they did make Cat tractors this small

Yeah, 4X4HIGH pointed that out when he came by -- he actually works for a big commercial rental place and they have them. If I had any sense at all, I prolly coulda rented one from them to do any actual work.

A little OT here, did you had the digital readouts to your mini lathe?

The DRO's came on it, donno if they're actually factory or part of the "deluxe" kit that LittleMachineShop sells. IIRC, they sell them separately too.

Did your broach come with the round solid stock that is sized to fit inside the drive slugs to make the keyway? I get the idea of how it works; I assume you just make multiple passes taking a little material out for the keyway each pass. How do you adjust the broach to take more material each pass?

Do you have enough Dewalt grinders? I assume each has a different disc on it so you can just grab the next one you need without having to swap discs each time. Awesome!

Yeah, I like me the Dewalts, and yeah, one for each head. (Plus a die grinder and a 7" for the heavy stuff. Just one of those though.) Saves time and wear and tear on the grinders, lets them cool down a bit between tasks.

Yeah, the broach kit comes with the inserts as well as the actual cutter, and then a coupla shims to do the multiple passes. The broach cutter proper is actually tapered, in that successive teeth extend just a nipple out further, so that as you go down it shaves more off.

Also, just so happened to drive by surplus center in Nebraska about 3 hours ago

Jealous. Really wish we had places like that here, but even the nearest Tractor Supply is like fifty miles out.

OTOH, I notice that Burden was outright closed the other week due to inclement weather. There is something to be said for the climate here

 

[dremu]

The design calls for "rock guards", to keep gravel out of the tracks. My environment is dirt and mud, so I'm not sure I really need them, but this whole project is not so much about actual need. Also, Because Diamond Plate.

Gotta love that Cardboard Aided Design. Didn't have a piece long enough, so the kid donated some of his alien duct tape to patch together two pieces.

One side's worth. The inside set are a pain to get to when the machine is on the ground, so this was all done while it was still on stands.

There's also carefully ( ) bent upper guards to deflect mud and rocks out of the tracks.

compare this pic to the above, though it's a bit later in the timeline.

 

[fastazz81]

I think that any project that gets are kids in the garage with us is worth way more than whatever we spend on materials or the tools to do it !

 

[dremu]

Spent a coupla afternoons attaching the grouser plates to the inner tracks, which is surprisingly difficult. There's not a ton of space and I couldn't make a right-angle adapter work. Ended up using a U-joint on the cordless impact. Attach the outer two nuts, get underneath and attach the inner two nuts, turn the track one unit, lather, rinse, repeat. Much as though I love me the grinders, the cordless impact is hands down the most useful tool for fab work.

The machine could finally move under its own power, so it came down off the stands for the last time, and I drove it over to the welder to put on the tabs for the upper rock guards

Also discovered how slow 1.8MPH is. Seriously, a nun in a walker going up hill is quicker than this thing. (At least the machine has more torque.) Took it out in the dirt

You can see the JD lawnmower behind it. They're about the same size, but the JD weighs about 1/5 as much The extension cord is for a trickle charger. I am contemplating using the dozer to trench a conduit out to the carport there so I can have power.

And the kid takes it for a spin. Wood pile off to the right, demo leftovers from when we bought the place.

 

[dremu]

I think that any project that gets are kids in the garage with us is worth way more than whatever we spend on materials or the tools to do it !

I should run that one by the missus. Might just convince her

 

[dremu]

There's a bunch of hinge points for the blade mechanism, as it lifts up and down, swivels left and right, and even rotates. All of these have brackets in the laser-cut parts, but for the forces involved, even two pieces of 1/4 steel isn't enough to spread the load. You put an inch or so of bushing on each end, therefore, and a longer pin through the cylinder or whatever.

To keep the pin in place, you drill through the bushing and the pin and pop a 1/4" clevis pin through. This isn't load bearing, just keeps the pin from sliding out. Here's a bunch of 1" pins with the one bushing end:

Some but not all have a another end bushing, just DOM cut to length.

The result is something like this

The yellow part is the lift mechanism. Center, horizontal, is a double-bushed pin point for the lift cylinder. The unpainted part attaches to the blade. Far left and right are the pins for the swivel (left-right) cylinders, and the odd one on the left is the bottom pin for the rotate cylinder.

Here's the lift mechanism a day or two before, test fit to the machine:

The bungie is obviously a very temporary arrangement as I plumbed and mounted the hydraulics.

The cylinders have grease zerks for the pins, so I center-drilled part of that big bolt (the joys of the lathe) and added a zerk to it too. I'd say "can't have too many zerks", but there's like 40 of them on the machine. Lubing it ... well, let's just say I bought a cordless grease gun

 

[dremu]

The swivel is done with more of the laser-cut parts, and a healthy dose of square tube:

Gotta say, those F-clamps are handy, so much quicker to adjust than a C-clamp. I got a coupla cheapos at the Harbor Freight on a lark, and found them useful enough I splurged on a coupla big ones at the local welding shop. They're brand name and were not cheap, but they are bigger and better made.

The lift hinges are cut out of the tube, and then a piece of 1/4 wall DOM welded in place. These are drilled for grease zerks as well.

The middle of the lift mechanism above is actually 2x3 tube, with rounded ends so the swivel can clear it a smidge more. This is capped with flat bar hammered into a loose approximation of a curve

and then hit with the flapdisc until it looks nice(ish)

 

[dremu]

The blade is (surprise!) 1/4" plate, and I'm not set up to bend something that size/thickness. (It's "only" four feet wide ) I considered doing three pieces and then welding them at the bend lines, but in the end just had the local place bend it for me. Looks nicer, simpler, less work. The blade has the center hole for the rotation mechanism, and then a slot at the bottom for a replaceable scraper (which is, surprise, 3/8 plate.)

Here's the back side. The grind marks under the nuts are 'cuz it's prepped zap the nuts into place as captive nuts, easier to work on that way.

There's a bit of booger welding went on here, as I mis-measured and had a small gap to fill, but overall it's solid. Also added a coupla Kert's tabs to the back, both to help move the piece around during assembly as shown, and for future lifting use. I have some railroad ties in the garden as dividers and such that may need moving, so why not use the dozer?

 

[dremu]

I do not claim to be a hydraulics expert, and kinda fumbled my way through this as a learning experience. (The plans had precisely one page dedicated to the hydraulics in the form of a vague, mis-spelled, and sometimes wildly inaccurate schematic.) I also wanted some of the controls to physically face a different direction than the others, which prevented me from using a multi-spool valve. (I thought it would be more intuitive to have a left-right lever for the left-right swivel, but having run the hoses, I kinda regret that )

Anyway, after much fiddling about and abuse of a loong stick of angle, the control panel frame came out like this

I also did up custom knobs on the 3D printer to label the controls and give some hand comfort. Left side is swivel (upper, left-right arrow) and rotate (lower, circular). Center is the tracks, labelled L and R, hopefully self-evident, and finally in the upper right is the lift cylinder.

The panel removes from the machine for service,. Upper left and top is the few electrical controls (electric start for the motor, light switch, and hour meter) and then mounts the various hydro valves. Captive nuts are welded on the back here as well.

and there it's painted and mostly plumbed. Oh My God, so many hoses. Did I mention regretting not using multi-spool valves?

I know it's a hairy mess. I did go through and clean it up a bit, and have another pass to do once I sort out using a tank return manifold instead of multiple tees. I'm also 3D printing up a bunch of hose clips to neaten the hose runs and keep them out of harm's way:

Yes, they're yellow to match. It's fun!

 

[dremu]

Oh yeah, lights. We know how Emu loves him his lights, but the electrical system on this machine is a bit lighter than the Blazer (it's like a 5A generator on a 350CCA lawn-n-garden battery.) LED is called for, obviously, and small ones at that. The front and rear are on opposite ends of a double-throw switch, so only one can be on at a time.

The plans just called for a square ROPS, but I opted for some a bit more aesthetically clever.

While the bandsaw CAN cut angles, you still have to measure them properly, and my trigonometry is apparently much worse than I thought. Took me a while to sort, as my plan was originally to do five pieces across the top arc, not three.

The back has two floods, so you can look over your shoulder, and then the front has a single bar that combines a center spot and floods on the sides. They're both Chinese cheapos, less than $30 for either set, so if they get rained out or shattered it won't break the bank.

Ran the wire down through the ROPS tube and out the bottom, kinda slick.

(again, pic out of timeline) And the front light in use

For a "30W" LED bar (and given the provenance of the thing, I doubt it's really that much), that's still a surprising amount of light.