Another Mini-Dozer

[Rusticus]

Rawinok2 -

First things first - incredible build, especially with the challenges you face. My hat's off to you.

I'm wondering if part of the trouble is that the track tension springs aren't stiff enough. The adjustment on the original Struck's was just a threaded rod (and frame flex) - pretty stiff, in any case. Similarly the Bolens Hus-Skis, an early "snowmobile" (of sorts). Can you have someone eyeball the tension mechanism while you shift into forward and reverse, the next time you run it, to see how much things move?

I wouldn't worry as much about the drive sprockets being the front ones, since almost all modern "fast" track layers (main battle tanks, for instance) have the drive sprockets in front. "Slow" track layers do usually have the drive sprockets at the rear (or up high) to keep the portion of the track which is in contact with the ground in tension (that whole "you can't push a rope" thing). The fast track layers are keeping the lower portion "limp" so that it can be more compliant over bumps and hummocks at speed. Horses for courses, as they say.

In either case, you aren't likely to be having issues due to the fronts being the driven ones, but I could imagine it's a bit difficult to "modulate" the controls if the sprockets are "walking" back and compressing the tensioning springs as soon as you try to move the tractor. If that seems likely to be the problem, I'd try cobbling something to "lock out" the spring motion (temporarily) and see if it behaves better. If so, using stiffer springs might be all the medicine it needs.

Again, great job on the build.

Kevin

 

[wrangler6831]

Rawinok2 -

First things first - incredible build, especially with the challenges you face. My hat's off to you.

I'm wondering if part of the trouble is that the track tension springs aren't stiff enough. The adjustment on the original Struck's was just a threaded rod (and frame flex) - pretty stiff, in any case. Similarly the Bolens Hus-Skis, an early "snowmobile" (of sorts). Can you have someone eyeball the tension mechanism while you shift into forward and reverse, the next time you run it, to see how much things move?

I wouldn't worry as much about the drive sprockets being the front ones, since almost all modern "fast" track layers (main battle tanks, for instance) have the drive sprockets in front. "Slow" track layers do usually have the drive sprockets at the rear (or up high) to keep the portion of the track which is in contact with the ground in tension (that whole "you can't push a rope" thing). The fast track layers are keeping the lower portion "limp" so that it can be more compliant over bumps and hummocks at speed. Horses for courses, as they say.

In either case, you aren't likely to be having issues due to the fronts being the driven ones, but I could imagine it's a bit difficult to "modulate" the controls if the sprockets are "walking" back and compressing the tensioning springs as soon as you try to move the tractor. If that seems likely to be the problem, I'd try cobbling something to "lock out" the spring motion (temporarily) and see if it behaves better. If so, using stiffer springs might be all the medicine it needs.

Again, great job on the build.

Kevin

I think you mis-understood, the fronts are not drive they just look the same as the rear.

 

[Renze]

"Slow" track layers do usually have the drive sprockets at the rear (or up high) to keep the portion of the track which is in contact with the ground in tension (that whole "you can't push a rope" thing). The fast track layers are keeping the lower portion "limp" so that it can be more compliant over bumps and hummocks at speed. Horses for courses, as they say.

Its not PUSHING a rope... its just pulling from the other end. When the drive sprockets are rear, the upper portion of the track tense just like the belts on old fashioned threshers: by the weight of the belt which hangs down between the sprockets and two or three idlers. also this allows for better track to sprocket contact, as a too slack track hanging down, will increase the contact arc on the drive sprocket. If it hangs slack on front, the contact arc will decrease and there is more chance of skipping teeth

Fast crawlers have drive sprockets up front so they pull the upper part of the track tight to reduce harmful vibrations at high speeds, caused by the polygon effect of a sprocket, which isnt round like a belt pulley, but transmits torque in several little jerks, as many jerks per rotation as there are teeth on the sprocket wheel. (imagine a V belt which bends in a perfect radius around the pulley, but a chain bends in several sections around a sprocket: this means the actual radius of the sprocket depends on sprocket tooth position, in relation to the horizontal part of the chain) the polygon effect is well known in chain drive applications, and limits the length of which a chain can run unsupported at a certain speed.

the track tension on the part that touches the ground is the same, but the part which is above ground keeps better tension when the drive sprockets are on the ground, reducing the polygon effect at high speeds.

 

[cschulz]

Happy New Year Bob!!! How are you feeling after the holidays? Good I hope.

I do have a question if you would. What size dia. are the track wheels and the bogies? And you used a 6" channel correct? Sorry if I asked this before.

Dont bother getting out to the shop for dimenions. Save your energy. Just what you can remeber off the top of your head.

Thanks and hope to see back at it soon,Chris

 

[hbs20]

Your project is amazing. I weld/fabricate for a living so I have an idea as to what goes into a project like that. You had mentioned finding the chain that Struck used on the original. Here is a link to some. Tisco Tractor Part Mart: Reliable Tractor Parts You Need. Fast :: ATTACH LINK (55K1) It is a bit expensive though. As for the hydraulics the jack shaft is an excellent idea. The majority of hydraulic pumps out there are only rated for 1200rpm. Most gas motors turn 3600 rpm I believe. That will eat a pump pretty quick. My idea is to use a power steering pump. They will only develop about 1200psi but for your needs I would like to think that it would be adequate. GM has a power steering pump that uses a remote reservoir. I feel that would work well because you would be able to use a large reservoir and you could mount it were ever you wanted. Hydraulic hose ends that will screw into a power steering pump are available. Good luck on getting it were you want it. Once again great JOB!!!

 

[rgs03833]

I've ordered some parts but that's about it.
Last weekend was not a good one for me. You may remember that I wrote about my accident at work which left me disabled (page 12). Well, I had another incident where my ankle started bleeding and would not stop until I lost a couple pints ! It was just getting started in the photo below. I usually have to get down on the floor and raise my ankle above my heart in order to get it to stop. The garbage bag catches most of the blood. I will probably be inactive for a few weeks trying to regain my srength.
It will probably be after the holidays before I post again. So you all have a great holiday season !

OMG!

First, I hope you get well soon. Your health must come first!
Second, that is Great that you are documenting this for all of us to see. Thank you!
Third, the Project is is getting there and is awesome...

Can't wait to see it done!

 

[rawinok2]

Happy New Year Bob!!! How are you feeling after the holidays? Good I hope.

I do have a question if you would. What size dia. are the track wheels and the bogies? And you used a 6" channel correct? Sorry if I asked this before.

Dont bother getting out to the shop for dimenions. Save your energy. Just what you can remeber off the top of your head.

Thanks and hope to see back at it soon,Chris

Sorry I took so long to answer. My condition has gotten worse.
My ankles and feet are loaded with painful ulcers and I just had another bleeding incident yesterday. The good news is I finally found a doctor (a dermatologist) that has taken a real interest in getting me fixed.
The track wheels or sprockets are 12" diameter and the bogies are 4".
The channel is 6".

 

[Short Game]

My condition has gotten worse.

You know we all hope for the best for you. Our best wishes that everything improves. We want to see this dozer doing its stuff too.

 

[ben2go]

Sorry I took so long to answer. My condition has gotten worse.
My ankles and feet are loaded with painful ulcers and I just had another bleeding incident yesterday. The good news is I finally found a doctor (a dermatologist) that has taken a real interest in getting me fixed.
The track wheels or sprockets are 12" diameter and the bogies are 4".
The channel is 6".

Good to hear you found a doctor that really wants to help.I am trying to get a few medical issues taken care of myself.I can't find a doctor I can afford.

 

[psdx]

Sorry I took so long to answer. My condition has gotten worse.
My ankles and feet are loaded with painful ulcers and I just had another bleeding incident yesterday. The good news is I finally found a doctor (a dermatologist) that has taken a real interest in getting me fixed.

Our family's prayers go out to you and yours. Get well soon.