Snow Thrower Chain Replacement

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Re: Snow Thrower Chain Replacement

Postby FarmallMan » Tue Mar 03, 2015 7:55 pm

Yes, if memory serves the motor needs to come out, or at least you need to disconnect the wiring to get enough play to let it swing below the side. Is your sprocket actually free (moving back and forth)? If so push it away from the shaft end, and use a flat file to dress the circumference of the shaft lightly and see if it will cooperate then. If not then you'll use a bearing puller, or bring it to a machine shop and let them play with it. Once it's free, polish the shaft with some scotch-brite and the new one should slide right on.

Mine was fully seized in place and had to be heated with the oxy-fuel torch and pulled off with a bearing puller and impact wrench. Even the set screws were seized, I had to weld nuts to them after stripping out the hex socket just to get them out.

Nick 8-)
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Re: Snow Thrower Chain Replacement

Postby jdunmyer » Wed Mar 04, 2015 1:02 am

Larry,
When you disconnect the wires from the motor, be sure to hold the eye on the wire with channellocks while loosening the nut. Or, if you have very thin wrenches, you can use one on the nut below the terminal eye, the other on the outside nut. Whatever you do, don't just wrench on the outside nut, or you're likely to spin the terminal bolt in the motor, and cause yourself serious problems.

Chain sprockets should be lined up as perfectly as possible, and the chain must be kept lubed. Yes, it's messy, but that's the only way it'll live. It's also a Bad Idea to install a new chain on worn sprockets, as the life of the chain will be severely shortened.

I'm unclear as to why you're working on this thing while it's still attached to the tractor. It's a matter of a couple of minutes to remove it, and things are much easier to work on then. FWIW: I hate to crawl around on the floor, especially at 71 years old. We drilled 2 holes and installed forged eyebolts, one just behind the motor sprocket, the other in the angle bracket that holds the chute swivel mechanism. We then made a chain sling, using 1/4" chain, 2 hooks, and a ring, so we can easily lift the thing onto a rolling table, using an overhead hoist. This will also make it easy to set the blower on a pallet for Summer storage.
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Re: Snow Thrower Chain Replacement

Postby EtnaInst » Wed Mar 04, 2015 2:38 am

Many thanks to Jdunmyer, Farmallman, and m_c_0101 for your very good suggestions. The old sprocket did in fact come loose after some application of heat (gently), WD-40, and a file to dress the end of the shaft. Now the issue is getting the new sprocket onto the shaft. While the old sprocket slides easily onto and off of the shaft, the new one doesn't want to slide on. It appears to have a hole that is about .1mm smaller than the old sprocket (based on a vernier caliper). A 7/8" drill bit has just a little more "play" in the old sprocket than in the new one. I'll break out the Scotch-brite and see if I can get the shaft polished enough.

The new sprocket is clearly marked 7/8", so it *should* fit... ;-)
Larry Chace, Ithaca, NY I-5 and E15
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Re: Snow Thrower Chain Replacement

Postby FarmallMan » Wed Mar 04, 2015 3:25 am

If the scotchbrite doesn't do it for you, then try some 220 emery paper - dress it lightly until the new pulley slides on. It should be a nice and shiny.

Nick 8-)
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Re: Snow Thrower Chain Replacement

Postby jdunmyer » Wed Mar 04, 2015 4:22 pm

Larry,
Be VERY careful that you don't go too far with that polishing, you can't put metal back on!

First, be certain that the motor shaft is clean and polished. Use fine emery cloth, ScotchBrite, or steel wool, but remove only rust, not metal. Also, check that the end of the shaft isn't mushroomed and that there are no 'boogers' on the shaft from setscrews or whatever. If the fit is "right", it takes nearly nothing to prevent the sprocket from going on. Your caliper should tell you if the shaft is mushroomed if you measure it in 2 or 3 places. You could even file around the end of the shaft, going back only 1/16" or so, just enough to remove any boogers at the very end.

If the sprocket does need to be polished out a bit, the best way is to use something like a split dowel in a drill press or even in a hand-held drill motor. You will thread some emery cloth through the slit in the end of the dowel and use that to polish the bore.

You'll want to not allow the polishing arbor to exit the bore, as it will cause it to become bell-mouthed. Also, even though your sprocket is new, check it carefully for any dings/deformation around the hole. When you get it "right", it will just barely slide onto the shaft without any sort of "persuasion". Resist all temptation to beat on it beyond slight tapping with a piece of wood or a LIGHT mallet.

I don't mean to be preachy, and I hope I'm not coming across that way, but I've "been there, done that", and screwed up enough times to have won the T-Shirt.
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Re: Snow Thrower Chain Replacement

Postby FarmallMan » Fri Mar 13, 2015 1:33 pm

Larry, how'd you make out? Any luck?

At least it's looking like the worst of the winter is breaking.

Nick 8-)
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Re: Snow Thrower Chain Replacement

Postby EtnaInst » Mon Apr 13, 2015 1:45 pm

Yes, the worst of winter is probably over now (though we still have some piles of snow out at the road).

I got the new drive sprocket to fit after carefully polishing the bore with some 220 wet/dry sandpaper wrapped around a piece of 1/2" black iron pipe (which is more like 7/8" in diameter). The sprocket then slid on just like the old one slid off. (A non-ET person suggested I torch the new sprocket to make it expand enough to fit, but I was worried that it might cool quickly enough that I wouldn't have time to install the chain and get the sprocket correctly aligned.)

The new sprocket had two set screw holes, a 1/4"-20 over the key and a 5/16"-18 a quarter turn away. I didn't have the larger size so I used the just the smaller one. The thrower ran nicely, for a while, but then it made a "different" sound when fired up. That was the result of the key having worked loose and falling out, at which point the motor shaft turned but the sprocket didn't.

A new pair of set screws and a bit of (removable) Lock-tite seem to have improved the situation, though there was not a lot of new snow and therefore the "opportunity" to use the thrower.

If the collective wisdom on this forum suggests that I should have used heat (rather than abrasives) to make the sprocket fit, I'm willing to get another new sprocket and "do it right".

Many thanks to Jim Coate for shipping a new sprocket and chain immediately upon receipt of an e-mail. This winter's snow and wind were quite a challenge and having to repair *both* tractors in the midst of it was no fun. (The E15 first lost all but electric speeds 1 and 2, and Steve Shore was kind enough to ship new components for the Card #1 after I found that the fault was there -- a blown unijunction transistor. Then it started doing strange things like running in reverse even though the speed control was set to forward. Harold Zimmerman suggested that I check the microswitches on the speed control. They were ok, but the control lever had come loose on the control shaft so that the lever position no longer matched the cam that operates the switches. Replacing the roll pin fixed that. Luckily, we were able to push the E15 back into its garage for repair; it wasn't heated but at least it wasn't out in the middle of the blizzard.)

*MANY* thanks to all 3 of our ET parts suppliers for their prompt provision of parts and advice!
Larry Chace, Ithaca, NY I-5 and E15
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Re: Snow Thrower Chain Replacement

Postby EtnaInst » Fri May 08, 2015 8:13 pm

After using the new chain and motor sprocket for perhaps 20 minutes, I put the machines into storage in the garage. No further snowfalls came this way, and so a few days ago I decided to removed the snowthrower from the I-5. First, though, it seemed prudent to take a look at things. Yikes! The motor sprocket had moved outward (away from the motor), perhaps 3/8". The chain was clearly running at an angle. Not good!

Looking carefully at the motor and the framework to which it is bolted, I noticed that the sprocket end was ever so slightly forward of the other end. (That is, the motor axis and the auger axis were probably not entirely parallel.) A "loaner" motor assembly had its motor's sprocket end if anything slightly *rearward* of the other end.

I also noticed that the motor mounting bolts weren't quite as tight as I might have hoped. Is it possible that the motor shifted so that the sprocket end was closer to the auger and that, as a result, the chain wanted to pull the motor sprocket outward? The two set screws seemed tight, though I was able to remove them without a massive application of leverage.

The sprocket is now back where it used to be, with about 3/32" of the motor shaft extending beyond the sprocket. The chain looks nice and straight. The motor has been shifted to be parallel to the frame to which it is attached, and the attachment bolts have been tightened as much as I could. The set screws have been reinstalled with Locktite.

It seems to run fine and the sprocket hasn't shifted, at least not after about 30 seconds of running.

I'm asking if those with experience in this area feel I should do anything else to prepare for next winter's onslaught.

Many thanks!
Larry Chace, Ithaca, NY I-5 and E15
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Re: Snow Thrower Chain Replacement

Postby jdunmyer » Sat May 09, 2015 11:44 pm

Larry,
As you're learning, a chain drive (all components) must be set up "right". That means that the shafts must be parallel, sprockets aligned, etc. The motor mounting bolts need to be tight, usually defined as "until just before they break".

If the sprocket is loose on the shaft, it might be time to use some LocTite to hold it. Best product for this application is "Sleeve Locker". You might have to get everything lined up, take some measurements, then remove the motor, clean the shaft and sprocket bore, and reassemble using the sleeve locker. Done properly, it's unlikely that the sprocket will move on its own, but it's fairly likely that you'll need some heat to get it loose next time.
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