Well it's been since April that I got somehow locked out of machinebuilders.net I can't log in there anymore and haven't had time to restart the thread here. I thought it was about time for an update.

A little back story. I was telling a friend at work about building a blade for my 4 wheeler that is powered by the winch. He told me about a website that sold plans to build various equipment. So I started looking at the Cadtrac and thought I could do that. Being cheap I didn't want to buy the plans. So I started studying pictures and looking for dimensions to reference. I pretty much drew up the Cadtrac on Solidoworks without any dimensions other than the main beam being 3" tubing. I decided I didn't like the deisgn too much. What turned me off was the long cantilever on the wheel motor frames and the single "spine" of the machine vs a more traditional square frame. Also the use of the wheel motors seems like it would cost more and be more likely to leak later. So I decided to start from scratch and design my own machine.

It started centered around the same specifications as the cadtrac but kept growing until it got to the size that it is now.

I will have to make some new renderings of the design as it has changed from the ones on the old site.

The thing that really kicked off the build was the purchase of a 45 hp Jimna tracton engine last September on Ebay. I got it for $620. It is brand new never been run or installed. It was a spare at a dealer that went out of business. So the loader is designed around this engine.



I have built brackets for the engine.



These go on the rear frame (upside down on the pic and not complete)



Here is the front frame. The shaft is 2-3/16. It will have two bearings that will give the side to side rotation. The holes in the plates will have bushings welded into them to hold hydraulic cylinder pins.

I have a few more parts cut out for the Jount piece. The main shaft will be 2 15/16 and go in 2 15/16 bearings. If the bearings fail the shaft will be going through 1/2" plates as seen on the third pic above. It is the wrong angle so you can't see the holes in the plates.

Here are some of the joint pics. closeup of the front joint 2-3/16 shaft.



Rear joint plates yet to be welded on.



Joint pieces. 3" hole in 1/2" plate with hole saw.



To hold all this up we have GM 12 bolt rear ends from a 3/4 ton 1975 chevy. I plan on using the axles as is unmodified with brakes hooked up.



I also plan on hooking up a steering cylinder to the front axle. This will let me switch between articulating and front axle steering. The front axle steering will be better for using 3pt hitch attachments.

My trailer I built is in the background.



and of course I have my little helper.



This is a rendering of how the joint will look when assembled.

A big challenge will be getting the drive shafts from the transfer case to the rear axle. I will have to have an intermidiate shaft and then the final angle will still be about 22 degrees on one of the shafts. I will figure all that out when I get a little further along.



To drive all this will be a hydraulic motor direct mounted into a np205 transfer case(same donor truck).



We got a 1975 3/4 ton with 12 bolt axles th 350 and a 1980 3/4 ton with same axles and np203 for $150 total.

gator my friend you have a NP203 transfer,it's not a 205.A 205 will have a bolt-on front adapter,with the 2 shift rods coming out of the front of the case,linked with a metal bar between them.The 203 is a full-time 4x4 transfer case,chain drive with a big wide chain inside,high and low ranges in the front part where your input shaft is.The 203 will work for you,just don't push it too hard with quick forward/reverse cycling,shock loading it.What kind of mileage was on the truck when you got it?(or it got you,depending)

I was just about to argue with you and I decided I better look up more pics. I did a lot of research trying to leard about these two style boxes and somewhere along the way got them backwards in my mind. Anyway I am planning on tearing down the other truck and getting the other transfercase from it also. It is the smaller case presumable a np205.

This case had about 50,000 miles on it. I don't know about the other one.

Thanks for the correction

Trying to make sure I understand here: The hydraulic motor is driven from the engine, right? Then the rest of the driveline is mechanical?

Your articulation joint looks a lot like some log skidders I've worked on. Should be fine, IMHO. Yeah, you probably need an intermediate shaft, or maybe just a double yoke U-joint(or whatever they call those things) if you are going to turn very short with it. That's what's in the skidders, and they REALLY get abused!

I plan on driving a pump off the flywheel of the engine and puting a hydraulic motor into the input of the transfer case. I hope to be able to get the drive shaft from the transfer case to the rear axle with an intermediate shaft. There is a loader close to my fathr in laws property that I looked at. It has a big gear box (transfer case)the output shaft goes to a second shaft that croses the machine pivot, it is supported with pillow block bearings. Then another shaft goes to the axle. So three shafts to get that 45 degree angle. If all else fails I will take out the transfer case and direct drive a hydraulic motor into each axle and plumb them like the cadtrac. I want to use the transfer case so I will have low and neutral.

That should work. If you are multiplying torque with the hydraulic drive, it might be hard on U-joints, but probably not, since traction is the limit there. Sounds like a winner!

FWIW, John Deere log skidders typically have a big hydraulic pump on the front of the engine, driven from the crank, that runs the winch, sterring, blade, and whatnot. Might be source for something reasonable, if they are around your area.

hey gator,not tryin to bust your ba**s on the 205 thing,it's just the 203 is a full-time case and might give you steering difficulties.Hope you're not cussin me at the dinner table.There is a part-time conversion kit available for the 203(maybe not now,the 203 is pretty old).anyway if it all possible try to direct mount the hyd motor right to the input shaft of the case,make a splined adapter.I used a roller chain side drive to drive my artic and it's broken twice now..I just havent hardened it enough yet.Make sure the hyd motor is accessible so you can remove it.oh,and definitely run a case drain if the motor is ported for it.You should be using a drive motor with enough torque to drive this tractor,most that do have a case drain provision on them.You might want to think about a crossover relief valve between the hyd motor and the controlling valve as well.

No cussing at the diner table. The other truck has a 205 on it (I think). We will tearit down to scrap before I get to installing transfer cases. I might put it on instead. I had planned on direct driving the hydraulic motor into the transfercase, that way I will avoid the side load that has broken your loader down.

It's my understanding that the 203 has a built in differential in the case and then the differentials in each axle. I don't know if the axles have lockers or anything in them. I was going to see how it worked before modifying anything. If I go as planned, it will basically be a trucktor without the truckpart. Full drive line from a 3/4 ton chevy.

I am guessing that the loader will weigh about 4,500 lbs when done. What kind of pull/push force can you develop before you spin tires? With the hydraulic motor I had originally picked out you would be able to push about 3000 lbs with 30" tires and low gear on a transfer case.

Anybody have an idea what the CadTrac is developing (push/pullign force)? It isn't as simple as torque X wheel radius x 4 motors because the flows are in series. I guess it might be torque of two motor because the fronts are in parallel with full pressure drop x wheel radius. In actuality the pressure drops across the front motors and the rear so you don't get the full torque from any one motor but less from all four.

thoughts?

gator,the first time I broke the driveline in the lil'loader I just picked it up with the forklift and carried it to the shop.The forklift is a 4000lb Hyster..once you run one for a while you can kinda tell what things weigh by how the forklift moves out under load(and the 'pucker'factor under your butt)-my guess the artic loader weighs around 3500lbs.I have not gauged the hydraulics,it just didnt get done when building it.The pump is a 2-section gear type.The relief valve on the drive circuit valve is set at the factory 2000psi,and I have yet to hit it under load.It will spin all 4 tires under load in low range,rear axle locked 4.11's,front posi 4.11's,with 23"x8.50x12 skid steer loader tread tires.The bucket will sink into a pile of soft dirt(when driven into)with little difficulty.I can push brush piles and 8'L x 24" dia logs around easily.I have to get it back into the shop to fix the drive chain idler and a few other things.Keep us posted with your progress,we all want to see photos of your machine build.

I have made a little progress in the last few weeks. I have the main frame together and am ready to try to put the axles on. Here are the pics.



The articulating shaft is 2-5/16 bearings from surplus center $10 each

The wheel travel or pivot is 2-15/16. The max pivot angle is set by the two 3/4" bolts in the 3/4" plate. I had to mill out one of the 2-5/16 bearing bolt holes a little to get it to line up. Everything turns very freely now.

I am only planning on using one hydraulic cylinder to start with. It goes in the bushed pin holes.

gator,it'l steer fine with one cylinder.just a little faster on the retract side.Nice effort and fabrication..The box tubing is really strong stuff.Are you gonna cap the ends of it? you could have bee nest problems later!! keep us posted on how it goes..

He's right about the nests. I've chased four wasp nests out of the tubes on my tracked backhoe. One in the 4 x 4 tube and the rest in the 2 x 2's. They really seem to like the open tubes.

Chris

Good thoughts on the wasps. I will cap the ones on the sides. The one on the front is planned to be a square receiver.

I had better do that too. I just shortened a couple of 2" tubes on my winch/hoe frame so they are now open to the wasps. I will cap them as soon as it stops raining.

Your machine is looking great!

Chris

you could make a combination block off plate/tow ring to cover the open ends.Maybe use a piece of angle to wrap the end all the way around,makes for a really strong joint.I put tow rings on all 4 corners of mine in case it gets hung up in the woods we can snatch it out..them skidder trail ruts are hell

cheap way to cap it touch foam.. and if you add enough it could help you float. just don't add it to the tires.. home owner tried that and it worked for a few weeks.. then he had to buy new rims and tires.. old flat spots.. it was cheaper then trying to scrape it off to re use rims..

I don't think this one will be floating when it's done. I think it will end up being about 4,500 lbs.

I do have a design question for the gang...

I was planning on putting on matching front and rear chevy 12 bolt axles and using a transfer case to provide neutral and low gear. The more I think about this I think it may be more work than it is worth. I would have to mount the transfer case, and then figure out how to make the universal on the drive shaft turn 45 degrees.

I have another truck to pull axles from. Here is what I am now thinking. Scrap the idea of having optional front steering (saves money on hydraulics and complication). Assumung the two axles have the same ratio use two rears. This would allow me to take the short front drive shafts from the truck and mount the hydraulic motors directly inline with the axles. I would put the motors in series like the CadTrac is. This would cost me an extra motor and bracket but I could sell the NP203 and the NP205 to make the dollar difference up.

I also was wondering if I could add a valve to the hydraulics going to the hydraulic motors that would short circuit from the pressure side to the other. That would let me open that valve and the machine would be in "neutral". If the alxes were turned the alxe would drive the motors and the fluid would just go around in a loop. Obviously I wouldn't have low gear this way.

Anybody ever done this?

I really like the 2:1 transfer case low range in the close quarters areas,it makes for very precise control and manouvering..use high range 1:1 for long range travel.I think if you leave out the transfer case you'll be sorry later.I got mine repaired over the weekend,pushed two loads of #3 stone with it..one 24cu in charlynn motor..very powerful in low range.I'd look for 4.11/4.56 gears in your axles,especially if you're gonna run bigger tires like 30"dia.I think the front steering could also give you complications with lifting stability of the loader..you want to keep everything in line as much as possible up front.Maybe the steer axle in the REAR of the machine,like the older Cat 922 wheel loaders had.Keep us posted.

Uh, but it's "articulated". Is more steering than that really needed?
Doc