Another Mini-Dozer

[mjncad]

I didn't consider those cutting systems because I figured it would be out of my price range.

If you can do the CAD work, that will save you a bunch of bucks as you're doing a big chunk of the work for them.

 

[Verticaltrx]

Neat project, I'll be following this.

I have a set of plans to build the Magnatrac 1800, the one that uses a 4spd transaxle. Hopefully someday I'll have the time to build it. Just looks like something fun to build and play with. I wanted to get plans for one of the newer ones like the MT 3000, but they seem real stingy about releasing any plans that use their current track system.

MT 1800:

One bit of advice, and you may already employ this technique, is the use of hole saws. I have found that any hole 1" and over is much easier to make with a good quality hole saw. All the Lenox ones I've used have been surprisingly accurate. I've made holes as big as 2.5" through 1/2" plate with them with great success. I like to drill a 3/16 pilot hole to line them up, then just go slow (200-500rpms depending on dia.) and clean the chips out often. I also keep a bowl of water nearby to occasionally dip the hole saw in to cool it. I stopped using cutting oil years ago in favor of water for any drilling processes. Saves a lot of time cleaning parts before welding and I haven't noticed and reduced life of the bits either.

Also, I really think if everything works well after an initial test run, you should send out all the undercarriage related parts to get professionally heat treated. It's not terribly expensive but will increase track and sprocket life by a lot.

Look great so far. :thumbsup:

 

[Short Game]

I like hole saws, but can't say that the tolerances are all that tight in my experience. But, it certainly makes sense to move less steel with the cutting edge. If one were to slightly undersize the hole with a hole saw and finish with a drill, how much would one want to be cutting on that last pass for things to work out best/easiest? I'm self taught and learned by doing. I may have always been doing it wrong, for all I know. I'm willing to listen to the voice of experience on these matters.

 

[NormL]

I like hole saws, but can't say that the tolerances are all that tight in my experience. But, it certainly makes sense to move less steel with the cutting edge. If one were to slightly undersize the hole with a hole saw and finish with a drill, how much would one want to be cutting on that last pass for things to work out best/easiest? I'm self taught and learned by doing. I may have always been doing it wrong, for all I know. I'm willing to listen to the voice of experience on these matters.

Me too SG! I too am finding inconsistencies when using the hole saws. If the hole turns out to be under size by a thou or two I'll use my die-grinder to smooth out and expand the hole. If the hole is oversize, I have been known to use crosstube cutoffs welded over the opening since the holes are usually for pins on the backhoe I'm building. As for using a twist bit for the final pass, that gets beyond the capabilities of my press drill real fast. I find that the bit will grab the edge of the hole and stall out the drill. My cheapo bits usually chip out when that happens.

 

[Short Game]

Yeah, when the hole is only there to bolt a couple of things together, no big deal. But when it is to accommodate moving parts under loads, thousandths of an inch get huge.

 

[rawinok2]

Verticaltrx:

One bit of advice, and you may already employ this technique, is the use of hole saws. I have found that any hole 1" and over is much easier to make with a good quality hole saw. All the Lenox ones I've used have been surprisingly accurate. I've made holes as big as 2.5" through 1/2" plate with them with great success. I like to drill a 3/16 pilot hole to line them up, then just go slow (200-500rpms depending on dia.) and clean the chips out often. I also keep a bowl of water nearby to occasionally dip the hole saw in to cool it. I stopped using cutting oil years ago in favor of water for any drilling processes. Saves a lot of time cleaning parts before welding and I haven't noticed and reduced life of the bits either.

Rawinok2:
I got quite a bit of experience with hole saws when I built my "Ground Hawg" back hoe a few years back. I didn't have my drill press rigged up to run at low rpms (620 was the slowest) and I had trouble with it sawing crooked if that makes sense. In other words, the sides of the hole would not be perpendicular to the surface.
I wish I would have known about cooling with water, I did have a big mess to clean up every time.

Verticaltrx:

Also, I really think if everything works well after an initial test run, you should send out all the undercarriage related parts to get professionally heat treated. It's not terribly expensive but will increase track and sprocket life by a lot.

Rawinok:
I like that idea ! I might just do that.

 

[Verticaltrx]

When I built my CAD Digger 628 a few years ago is when I really started using hole saws. What they are excellent for is if you need to cut a large hole through plate to weld a bushing in (lots of those on a backhoe). In that case the tolerance isn't that important since you are welding the bushing in anyways. I did find however that surprisingly most of the holes fit the mechanical tubing with pretty close tolerances, so they can be accurate. I think it may have to do some with the setup also. I was using brand new hole saws and on a pretty good drill press (heavy old Delta-Rockwell). Also had the work firmly clamped to the table. I have a second drill press now that is a cheapo with a lot more spindle run-out and it isn't as accurate with the hole saws. I think that run-out is greatly magnified with a hole saw for what ever reason. With that said, I do use drill bits for anything that is fairly precision. If it's just a pin hole on a piece of farm equipment or to weld in a bushing then hole saws work great.

 

[NormL]

When I built my CAD Digger 628 a few years ago is when I really started using hole saws. What they are excellent for is if you need to cut a large hole through plate to weld a bushing in (lots of those on a backhoe). In that case the tolerance isn't that important since you are welding the bushing in anyways. I did find however that surprisingly most of the holes fit the mechanical tubing with pretty close tolerances, so they can be accurate. I think it may have to do some with the setup also. I was using brand new hole saws and on a pretty good drill press (heavy old Delta-Rockwell). Also had the work firmly clamped to the table. I have a second drill press now that is a cheapo with a lot more spindle run-out and it isn't as accurate with the hole saws. I think that run-out is greatly magnified with a hole saw for what ever reason. With that said, I do use drill bits for anything that is fairly precision. If it's just a pin hole on a piece of farm equipment or to weld in a bushing then hole saws work great.

I agree with your assessment of the cheapo drill press. That's what I have and when the bit was new the holes were pretty close. Now, after about a dozen holes into 1/4, 3/8, and 1/2" steel, I find I'm using the die-grinder a lot more, reaming and smoothing the holes for fit.

I saw a neat idea to slow down my spindle speed on another thread. I hope to try that and see if that will help for accuracy.

 

[rawinok2]

Question how many track pads did you make per side? Looks great!!:thumbsup: Loren

34 per side. Thank You.
Today I got a little ahead of myself and started welding before I had all of the figuring done. I didn't allow enough room for the front sprockets to adjust all of the way backwards.:ashamed: But after a few modifications, I think I'm OK now. Also, I welded the hubs onto the sprockets.

 

[cschulz]

These are very cool projects and your is really nice. If you are looking for Diesel engines look here.
Chris
Electric Start