Removing stuck gear

MJMJ · Jul 20, 2020

An tricks for removing a gear/sprocket from a shaft? Trying to remove a drive sprocket from a haybine top roller. Initially I had to drive it on further to remove the key and it moved pretty easily. After key was removed I put a 3 jaw puller on it and it moved back to the original position and that's all the further it'll go. I probably should have burnt the paint off the shaft first...
I've heated it as hot as I can get it with oxy/acetylene torch, and hit the puller with an impact. Broke one puller, but barely budged the sprocket. Now I can't even drive it back on further, just seems stuck.

I considered just cutting the sprocket off with the torch and replacing it, but at $120 I'd prefer to re-use it.

BarnyardEngineering · Jul 20, 2020

You galled it to the shaft. It is now for all intents and purposes welded on there and the only way to remove it is to cut it off.

Always clean the shaft down to bare shiny metal and add lube before you attempt to pull it.

Michael Soldan · Jul 20, 2020

I think it can be saved. Heat and cool a couple of times. Can you get a bottle jack behind it and shove it off? I don't think heating it has
caused it to weld to the shaft. Pry bar, fulcrum, penetrating oil..keep working on it..it went on so it has to come off. Check it is straight
on the shaft and not binding on one edge.

jimtrs · Jul 20, 2020

(quoted from post at 11:57:01 07/20/20) You galled it to the shaft. It is now for all intents and purposes welded on there and the only way to remove it is to cut it off.

Always clean the shaft down to bare shiny metal and add lube before you attempt to pull it.

Agree

Clean everything first is a must.

I'll also add, use heat only when everything else won't work, and you feel pretty confident that the heat will work. In my experience jumping to heat to quickly sometimes causes more problems. If the piece doesn't come off when heated, sometimes corrosion, rust, etc has know been disturbed, and when the piece cools back down it may be impossible to remove. Then it's time to dissect.

37 chief · Jul 20, 2020

That's just what was about to say. Stan

MJMJ · Jul 20, 2020

No room to do much other than put a puller one it. I still think it'll come off. My neighbor stopped by and we managed to drive it back on 1/4" - 5/16". So I'll clean the shaft up with a grinder, add some lube and try some more.
The heat wasn't the first step. I tried with only the puller for quite a while. My mistake was not cleaning the shaft, for some reason I didn't even think of it until it was too late. It moved so freely before I must have assumed it would come right off.

steve_in_mo · Jul 20, 2020

Last ditch effort:

Heat the sprocket and put candle wax on the shaft.
Let the wax melt into the space between the pieces if it will.
Do that a couple of times.

Put the shaft in a vice and Set up your puller, then get the
sprocket hot and put ice/dry ice on the shaft.
At this point, you don't have much to lose.

Ellis Kinney · Jul 20, 2020

I have had occasional luck by tightening up a puller and lube it and leave it for a period of time. Tighten a little more, be patient. Another trick, heat
a little and put candle wax on the joint, do not heat red, just enough to melt a candle. Ellis

showcrop · Jul 20, 2020

(quoted from post at 09:37:48 07/20/20) No room to do much other than put a puller one it. I still think it'll come off. My neighbor stopped by and we managed to drive it back on 1/4" - 5/16". So I'll clean the shaft up with a grinder, add some lube and try some more.
The heat wasn't the first step. I tried with only the puller for quite a while. My mistake was not cleaning the shaft, for some reason I didn't even think of it until it was too late. It moved so freely before I must have assumed it would come right off.

It should come off fairly easily now that you have grease under it. You could drive it back and forth over that range adding grease each time.

Dennis Minn · Jul 20, 2020

MJMJ,

I hope this doesn't undertalk your experience, but here goes....

Did you tighten the puller, then "rap" the end of the puller with a hammer?

D.

MJMJ · Jul 20, 2020

It's almost there.
I did try smacking the end of the puller yesterday, but to be honest my puller leaves a lot to be desired so I didn't put a lot into it.
Once we were able to drive the sprocket back on a little, I cleaned up the shaft with a grinder, heated the sprocket a bit and used the candle method. Then I used the impact on the gear puller and it would move about 1/8". Then I would heat a little more and add more wax, hit it again and it would move another 1/8". Repeated this until it had moved about 3/4" and the little 3/8 impact couldn't move it any more. Got the 3/4 impact but a bracket on the puller is broke. Letting it cool down so I can fix it, then I'll try to get it the rest of the way off. I think if I get it another 1/2" it'll be home free. I appreciate all the suggestions. If I can get this haybine through this year it's headed to the scrap yard next year. It's just not worth the headache any more.

retired farmer · Jul 20, 2020

If there is any paint or rust on the shaft it needs to be cleaned off first. It probably got stuck to the paint when you tried to pull on it.

Patsdeere · Jul 20, 2020

When you heated it, did you hear the whole
thing or just 1 line from center to
outside? If you haven't tried the line
heat trick, give it a shot. Works pretty
swell (especially if the shaft is clean).

Mike(NEOhio) · Jul 20, 2020

Clean the exposed end of the shaft down to shiny metal. Even if it doesn't look real rusty it's actually a bit larger than the metal under the sprocket

showcrop · Jul 20, 2020

Back and forth is the key with a little more grease under it each time. Heavier artillery is good up to the point where something breaks.

old-9 · Jul 20, 2020

Forget the grinder not able to control it.Emery cloth is your BEST bet. I have seen millwrights use emery cloth and crocus cloth for hours on a shaft, it has to fit right. When you go to put the sprocket back on clean/sand it also. I use an old welding rod with about 2 inches bent back onto itself, put a strip of the emery cloth in the "hair pin" fold- put into a drill and you have the perfect sanding tool for the sprocket. Finesse it don't force it. Luck, joe
your friend

Moonlite37 · Jul 20, 2020

Each time you heated it and allowed it to cool, the sprocket became tighter to the shaft. Heat once and pull while hot. If you heat the shaft, allow to cool

steve_in_mo · Jul 20, 2020

Sort of like the guy that cut wood all day with his new chain saw, and only got half a pickup truck load.
Took the saw back to the dealer.....

steve_in_mo · Jul 20, 2020

Salesman pulled the starter cord, and the engine roared to life.
"What's that sound?" asked the customer...

showcrop · Jul 21, 2020

(quoted from post at 16:03:31 07/20/20) Each time you heated it and allowed it to cool, the sprocket became tighter to the shaft. Heat once and pull while hot. If you heat the shaft, allow to cool

Moonlight I'll bet that MJMJ had no intention of heating it more than once. He told us that he got it as hot as he could with the O/A. I have never heard that simple heat-cool cycles cause metal to contract. Have you never been in a similar situation?

72supr · Jul 21, 2020

Crap happens.Hope you got it going.

Removing stuck gear

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