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Looking for Snow Trac Chain Drive sprockets ST34

danoneal

New member
Is there anyone out there who knows where I might find both large ST34 chain drive sprockets as both mine have broken teeth? I have found a local machine shop who can make them for me but $$$. I'm not sure if I am posting to the right place or how to but let's give it a shot. Any help would be great. Dan
 

JimVT

Bronze Member
GOLD Site Supporter
it is kind of slow now but the subject has come up in the past.
maybe a search?? Someone must have put a us chain on it. they are hard on the metric sprockets.
 
Another option is to buy a pair of new sprocket plates and machine your original sprocket hubs and the new sprocket plates to be fit and welded to each other. It would be a simple process for any machine shop, maybe a couple hours or less of labor.

I've done it on my rear sprockets, the small ones. I converted them from original 12 tooth to 18 tooth.

Hint: If you choose a sprocket with a number of teeth divisible by 3, it will be much easier for the machinist to chuck it into the lathe, so less cost to you.

The ASE version of the sprocket pitch is 80. Use the "A" identifier for a sprocket with no hub, just a small bore. And then choose the number of teeth you want. Just a quick search for a 80A36 sprocket on eBay comes up with a 36 tooth TRITAN sprocket for $55.10 plus shipping.

Observe:
http://www.ebay.com/itm/TRITAN-80A3...669141?hash=item1c858c9c95:g:JW8AAOSwlndZGy7O

Here're a couple pics of the ones I made:
 

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JimVT

Bronze Member
GOLD Site Supporter
Another option is to buy a pair of new sprocket plates and machine your original sprocket hubs and the new sprocket plates to be fit and welded to each other. It would be a simple process for any machine shop, maybe a couple hours or less of labor.

I've done it on my rear sprockets, the small ones. I converted them from original 12 tooth to 18 tooth.

Hint: If you choose a sprocket with a number of teeth divisible by 3, it will be much easier for the machinist to chuck it into the lathe, so less cost to you.

The ASE version of the sprocket pitch is 80. Use the "A" identifier for a sprocket with no hub, just a small bore. And then choose the number of teeth you want. Just a quick search for a 80A36 sprocket on eBay comes up with a 36 tooth TRITAN sprocket for $55.10 plus shipping.

Observe:
http://www.ebay.com/itm/TRITAN-80A3...669141?hash=item1c858c9c95:g:JW8AAOSwlndZGy7O

Here're a couple pics of the ones I made:

your still running the metric chain? how many hrs and is this holding up ok?
 

300 H and H

Bronze Member
GOLD Site Supporter
it is kind of slow now but the subject has come up in the past.
maybe a search?? Someone must have put a us chain on it. they are hard on the metric sprockets.

Yes the rollers on SAE #80 are not wide enough and catch the sprocket, damaging the teeth.

Get the correct chain, and this problem will fix itself.

Regards, Kirk
 
your still running the metric chain? how many hrs and is this holding up ok?

No. An SAE 80 chain, to match the SAE 80 rear sprocket. If I experience excessive wear on the front sprockets, I may very well be doing the same job to them, no big deal. I had a guy offer to make me a custom set of rear sprockets identical to the original ones for $800. Jesus, why spend that kind of money when they can be updated to modern specs for a fraction of the cost? It cost me $60 for the new sprocket plates I used, plus whatever time I spent doing the machining. I think the new #80 chain was pretty cheap also.

I guess you'd have to be a purist to want to spend 10 times more just to keep things as they were 50 years ago.
 
Yes the rollers on SAE #80 are not wide enough and catch the sprocket, damaging the teeth.

Get the correct chain, and this problem will fix itself.

Regards, Kirk

The sprockets can very easily be machined to trim the width down a tiny bit to address the issue you're describing.

How does replacing the chain fix broken sprocket teeth?
 

300 H and H

Bronze Member
GOLD Site Supporter
The sprockets can very easily be machined to trim the width down a tiny bit to address the issue you're describing.

How does replacing the chain fix broken sprocket teeth?

Sorry will not "fix" dinged teeth. Machining down may remove the surface hardening if a sprocket is not through hardened. Metric sprockets if you can find them, or convert both to SAE and us No 80 roller chain. Just never mix the two.

Regards, Kirk
 

danoneal

New member
Thanks everyone. yes I do plan to change out both drive chains not sure how old they are but it sure seems to the the major factor in breaking gear teeth. wish I had the knowlage and equipment to machine my own. Do you have the specs for the inside spline?
 

danoneal

New member
I guess I would be looking for the spline size for both sprockets if I were to convert to standard size sprockets and chain. Are the small sprockets not cast like the large front sprockets?
 
I guess I would be looking for the spline size for both sprockets if I were to convert to standard size sprockets and chain. Are the small sprockets not cast like the large front sprockets?

The small rear sprockets are steel, the fronts are cast iron. If you really intend to have both front and rear 100% manufactured, you would be best to remove at least one of each and have them available for your machine shop to study and duplicate. Keep in mind, in addition to the spline features, there're multiple hub features that will need to be copied. There's an oil seal surface on the rear ones, and if I remember correctly, the fronts have a spacer ring that mates to the sprocket hub on the outboard side. Of course, the tooth pattern will have to be custom, for whatever chain size you'll be intending to use.

I would only leave the task of manufacturing the sprocket teeth in the hands of a VERY skilled machinist.

If you really intend to go this route, you'll be spending a small fortune just for these custom parts. I would guess at least a couple of full shifts of machining time. For a shop rate of $125/hr, I'm betting you'll have $2500-$3000 or more wrapped up in it.

I encourage you to strongly consider the simpler and cheaper method I discribed in my earlier post from a few days ago. You'd be using inexpensive, manufactured sprockets that you know will have correct industry specs, and mating them to your own sprocket hubs. It really is a simple job and will give you the same or better result. I've actually done it, and it only took a couple of hours of machining time.
 

redsqwrl

Bronze Member
GOLD Site Supporter
Alaska Jay hit it right on the head.

If you are confident that you will never want your original final drive ratio back. having the sprockets made out of the old ones is the way to go.

If you want both ranges available source out the recreated sprockets.

I am not sure I have the ability to weld those larger sprockets, FF member utah wilson has a nice documented thread with welding cracks in the sprockets it did not go well as the internal stress of the weld kept recracking, maybe baking them after welding would reduce some of that stress. FWIW I think those sprockets are cast.

Not any kind of expert just a guy trying to keep 268 and number 17 alive.
 
FWIW I think those sprockets are cast.

Yes, the front are definitely cast iron. The rears are carbon steel but the teeth themselves are either hardened during manufacturing, or hardened from general use. They didn't want to machine off very well. But once I got past the teeth, no problem.

Welding the front cast sprocket hubs to new steel sprockets would be a challenge, but entirely possible.
 

Snowtrac Nome

member formerly known as dds
GOLD Site Supporter
it can be done with a high nickel rod and proper heating and cooling I found this winter another thing that breaks teeth are bad chains check for end play in the links if the bushings in the chain are worn the chain will walk up the sprocket
 

danoneal

New member
I did not think you could weld a cast part? But you are telling me that a steel sprocket can be married to a cast hub. And no I don't want to change out all sprockets but can I get a steel metric sprocket? the one you gave me a link to is standard but that still leaves a metric sprocket on the small end.
Dan
 

MNoutdoors RIP

Gone But Not Forgotten
GOLD Site Supporter
Steel can be welded to cast iron with the right process.

You maybe can find a sprocket with the correct original metric dimensions but I'm not sure how they're expressed, ISO 16, I think. Do a search and see what's available.
 

nikos

Active member
Alaska Jay.

I would only leave the task of manufacturing the sprocket teeth in the hands of a VERY skilled machinist.

If you really intend to go this route, you'll be spending a small fortune just for these custom parts. I would guess at least a couple of full shifts of machining time. For a shop rate of $125/hr, I'm betting you'll have $2500-$3000 or more wrapped up in it.

I encourage you to strongly consider the simpler and cheaper method I discribed in my earlier post from a few days ago. You'd be using inexpensive, manufactured sprockets that you know will have correct industry specs, and mating them to your own sprocket hubs. It really is a simple job and will give you the same or better result. I've actually done it, and it only took a couple of hours of machining time.
[/QUOTE]


In few years (the next decades) we would not only need to leave the task of manufacturing the sprocket teeth in the hands of a VERY skilled machinist but in a 3D Technology, 3D System industry with Printer and Scaners + manufacturing soft ware or Hard Ware (Design - engineering ) transforming and create prototype products -spare parts for our Snowtracs and Snowcats.

https://www.nasa.gov/mission_pages/station/research/news/3Dratchet_wrench

The Space technology has manufactured the first 3-D printed object in space

https://www.nasa.gov/content/international-space-station-s-3-d-printer

Nikos
 

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nikos

Active member
As we talking about 3D Printing materials, except the plastic and the polymers, there are also Stainless steel 3D Printing Materials for the 3D Gear models ( Metal Sprockets) or the Chain Drive models, frames, spare parts etc.

Metals are the strongest materials available in the market, but they are still extremely expensive. Metals include steel, aluminum, titanium, copper, silver, gold, nickel, cobalt, along with various others.

http://corporate.renault-trucks.com...ure-for-lighter-and-more-compact-engines.html

http://hackaday.com/2017/01/29/light-rider-a-lightweight-3d-printed-electric-motorcycle/

nikos.
 

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Snowshadow

New member
Metal 3D printing has come along way. I just got back from Oak Ridge National Laboratory a couple of weeks ago. We were there to see how we could utilize printing for Reclamation. Current costs run between $700-$900 a cubic inch for metal. The first photo is a gear set that cannot be taken apart because each piece is printed at the same time and in place.the 3rd photo is a continuous chain for the gear set. The 4th photo is a titanium test which is basically a robot welder (that was used to print a mini-hoe). The Jeep body was printed in composite with a layer sprayed over the top, much like a self leveling paint.
 

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zspryte

Member
Site Supporter
Metal 3D printing has come along way and still has a long way to go. Current problems range from porosity to high residual stresses to poor micro structure. These issues make 3D printed parts unacceptable for many applications today. The field is advancing quickly so maybe sooner than later snow trac sprockets will be printed.
 

Cidertom

Chionophile
GOLD Site Supporter
Direct 3D printing of high stress parts has a long way to go. But for doing prototyping and such for castings, wow. The ability to print a reasonably firm model of the item for size checking, then print it again, scaled up for the shrinkage, with a wax, for casting makes it wonderful for the one (or few) casting projects.
 

danoneal

New member
OK I'm still on the hunt. Does anyone have the original metric chain specs? This will match the original small drive sprocket then I can find a matching metric sprocket plates. Hopefully then I can find a mechinist who can weld cast hub to steel sprocket plates.
Thanks everyone.
 

JimVT

Bronze Member
GOLD Site Supporter
I put this on mine last summer I think you may be able to look it up
CHAIN-16BRB-HIT
BRITISH STANDARD INSPIRE 16B sch-04/11/16
 

danoneal

New member
Thanks,
Do you know the difference in the HIT-16B-2RB and a 16B Metric Roller Chain (British Standard)? Other than the $380.00 price difference.
 

redsqwrl

Bronze Member
GOLD Site Supporter
Just to recap this thread, dan oneal needs large sprockets.
I assume they are 36 tooth. for the ST-4.

Dan I would be willing to bet I can get a 36 tooth or a 42 tooth large sprocket.

I am sure that they are available metric or standard.

I am not sure the spline I had reproduced for the output of the trans axle is the same as the large sprockets inner. ( I am guessing from memory they are not)

If it is the same, I would be happy to have large machined sprockets created for you. as I need one as well.
Mike
 

danoneal

New member
Mike,
That is correct 36 tooth I'm not sure if the splines are the same I have not remoced the trans axle sprocket. I do want to keep the metric chain and sprocket as my trans axle sprockets look good and don't want to replace them if I don't have to. You don't know the difference in chain between HIT-16B-2RB and a 16B Metric Roller Chain (British Standard) do you. And yes I have not found a machinist to work with.
Dan
 

redsqwrl

Bronze Member
GOLD Site Supporter
Hit 16 B 2 RB is unknown to me. I searched it appears from the random targeted google search it is a Hitachi 16B chain. (given the 16 designation I would be tempted to think it is metric)
what I do know is the ansi 80 chain is .625 wide rollers.
and 16B has .670 wide rollers.

It appears that when folks changed out their chains on their snow tracs they installed the narrower chain and it attacked the cast sprockets. I suppose they figured the lube would make it all good and never looked back.
(previous 50 year lives of these machines will always be a mystery)

I will be examining some of this in july at the summer workshop. Of the three snow tracs getting serviced there are chain and sprocket issues on two of them. the extent will be *discovered* then.
Issues:
One has the chains removed
one is getting overdrive installed
one is completely unknown as the hood is stuck down, and I will let the owner pull harder on it. ;-)))))

Mike
 

JimVT

Bronze Member
GOLD Site Supporter
Hit 16 B 2 RB is unknown to me. I searched it appears from the random targeted google search it is a Hitachi 16B chain. (given the 16 designation I would be tempted to think it is metric)
what I do know is the ansi 80 chain is .625 wide rollers.
and 16B has .670 wide rollers.

It appears that when folks changed out their chains on their snow tracs they installed the narrower chain and it attacked the cast sprockets. I suppose they figured the lube would make it all good and never looked back.
(previous 50 year lives of these machines will always be a mystery)

I will be examining some of this in july at the summer workshop. Of the three snow tracs getting serviced there are chain and sprocket issues on two of them. the extent will be *discovered* then.
Issues:
One has the chains removed
one is getting overdrive installed
one is completely unknown as the hood is stuck down, and I will let the owner pull harder on it. ;-)))))

Mike
yes it is metric . I put the correct one back on . my sprockets are still in good shape.
 
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