Removing a stuck gear from a shaft

[gewf631]

Think I've almost exhausted my options, but never hurts to hit-up the collective wisdom of GJ

Sprocket is on a snowthrower (JD 510 tractor, M03280 snowthrower) - so parts are mostly made of unobtainium.

I've tried heat (propane and MAPP), PB-Blaster and wax, hammers, and a 3-jaw puller. I can get it to slide maybe a 1/16" in/out, but never far-enough!

Just looking for any suggestions, or maybe another set of eyes (or a few hundred), will help me see something I've missed.

Thanks in advance

 

[TheEquineFencer]

Step up to an OA torch with a rosebud...

 

[ez-duzit]

More heat and a bigger hammer.

 

[TheEquineFencer]

More heat and a bigger hammer.

 

[OccupantRJ]

Sometimes set screws are stacked in a single hole. I remove all set screws and look into the hole with a flashlight to verify. I have had a few items where I had to drill and tap the hub to provide for a puller closer to the center. Pulling on the sprocket OD can cause it to dish and bite the shaft in some cases. More heat and penetrant soaking is likely needed, most likely. If someone in the past has beat on the shaft, it could be mushroomed, and it will not come off without dressing it properly. Power wire brush the area and look really close at it.

 

[lis2323]

Mapp/propane will prob be too slow. Oxy acetylene would work better if it stubborn. Heat up the gear HUB cherry red for it to expand and use puller or pry bars before too much heat transfers to the shaft. Heating the whole assembly won't accomplish much.


Sent from my iPad using Tapatalk

 

[ez-duzit]

...If someone in the past has beat on the shaft, it could be mushroomed, and it will not come off without dressing it properly....

Good point. You can't just beat on the end of the shaft without using a punch.

 

[gewf631]

Thanks for the suggestions.

I did look REALLY carefully at the set screws - only one screw there, but 2 holes.

I think I'm the first one who ever attempted to get it off - it was virgin before I started. I've been using a punch, or just hitting the end of puller, so no mushrooming of the shaft (just some denting of the gear from my attempts)

I've seen a few recommendations for heat, following by a quick spray of dust-off on the shaft (a quick super-cool).

If that doesn't work, guess I'll have to upgrade my torch set.

Thanks again.

 

[Mechtech]

If its sliding a 1/16 each direction its not stuck.(unless the movement is the entire assembly) Something is bent or still fastened, can you get enough bite on the key to pull it first? ( vise grips wth slide hammer) Hard to tell from the pictures but I would work on getting the key to move seperatly from the sprocket/shaft.

 

[Jazz1]

More heat, Mapp or propane not hot enough. Oxy/acetylene and 3 way puller.

 

[claymont]

• Drive sprocket back as far as it will go, make sure puller can be installed
• File or grind end of shaft to make sure there is no burr
• Install puller put a lubricant on screw tighten as much as possible
• Use an impact driver or gun on puller screw
• Heat with your torch and drive puller screw with impact
• Keep heating and driving constant tension and impacting is the key it'll move

 

[55bigblockcid]

I`m wondering if you could drill and tap through the gear on opposite sides of hub and then thread bolts in and tighten the bolts to the other side of housing to push the gear off.Some pulleys have threaded holes for this .Still may need to heat the hub to get it off.

 

[OccupantRJ]

Cleaning and dressing the protruding shaft will definitely help. A few thousandths of rust interference makes a big difference.

 

[Snaparxon]

Set screws create a lip when the press into a shaft or key, this lip catches on the set screw hole and the lip try's to gall to the shaft. Drill and tap the key, or drill the key then use a self drilling-self tapping screw. Thread in until you can use a couple of pry bars to pull the key out. When the key is out you will be able to rotate the the gear and the key slot will fit over the high spot on the shaft plus.
I cant tell how much key you have sticking out but I have used a piece 3/16" by 1" flat steel with a nut welded on end. Cut a notch in the opposite end that just fits over the exposed key, to protect from accidental welding on the shaft, and weld to the key. Use a slide hammer to remove the key.

The closer the puller jaws are to the shaft the better your puller will work. I don't no how many ton your puller is rated for or if you have a two jaw puller but you can cut two slots opposite each other so you puller jaws are able to go through the gear and pull on the back side of the hub. I would use a 10 ton 2 jaw puller for this method.

How much is a new gear? Cut off the old one with a torch, clean up the shaft and replace the gear. Around here you can make your own gear, buy a sprocket that has the right pitch and tooth count, buy the hub with the correct I.D. and weld together. The hub has a pilot that fits semi tight in the sprocket to keep it true while welding. Also look on the web, I found this as an example,https://www.rollerchain4less.com/Finished-Bore-Sprockets_c_21.html

 

[Jazz1]

Cleaning and dressing the protruding shaft will definitely help. A few thousandths of rust interference makes a big difference.

^^that's likely all that's preventing the sprocket from falling off at this point

 

[matt_i]

I wouldn't even mess around with a straight bore sprocket.

Assuming you can get the sprocket via # of teeth and the roller chain size, order it with a taperlock hub. I prefer the QD/SDS hubs with a flange, but there are numbered series of taperlock bushings which are flush.

The taperlock squeezes the shaft as its tightened in addition to using the keyway but in general its better at longevity, especially when you have non-constant shaft loads, shock loading (or anything reversing of which this is not). A slip-fit shaft/bore interface has to be tight in order to be long-lasting which defies easy assembly (and disassembly).

If you did put the same sprocket back on, I would consider using a milling machine to drill and tap a 4-bolt threaded hole pattern into the body of the plate sprocket (roughly halfway between hub and minor root diameter of the teeth. In the future you could then use something like a slide-hammer and a simple crossbar to pull the sprocket without fear of damaging the teeth.

 

[Bottlecapdigger]

Well, did you get it off? BCD.

 

[kbs2244]

I vote for cleaning up the shaft with a file and then using the impact gun on the puller.

Or a new gear.
Check around on gear mfg web sites.
It is sure to be a catalog item somewhere.

 

[ez-duzit]

If the end of the shaft has been peened over, just grind it off flush with the sprocket hub.

 

[gewf631]

can you get enough bite on the key to pull it first?

Early-on, I (stupidly) hammered the key back - in hindsight, I should have pulled-out the key, then probably could have rotated the gear on the shaft and twisted it off.

Thank you for the suggestion

 

[gewf631]

I`m wondering if you could drill and tap through the gear on opposite sides of hub and then thread bolts in

Don't think there's enough room behind the pulley (between the pulley and the housing) to make this happen - it's maybe a quarter-inch

Some pulleys have threaded holes for this

If only it were like a brake rotor!

Thanks for the suggestions

 

[gewf631]

drill the key then use a self drilling-self tapping screw. Thread in until you can use a couple of pry bars to pull the key out.
... Use a slide hammer to remove the key.

Thank you - this sounds like an excellent next step (worse case, I booger-up the keyway a little, far better than breaking the gear)

The closer the puller jaws are to the shaft the better your puller will work.

The puller is pretty hefty. I agree about the geometry, but not really a way to get the jaws close to the shaft. Furthermore, I can't believe that force on the outside of the gear, would impact the gear's hub (that's a pretty hefty piece of metal)

I found this as an example,https://www.rollerchain4less.com/Finished-Bore-Sprockets_c_21.html

Thank you - I know the part is N/A from JD, but realizing it's a 1" shaft, it shouldn't be that hard to find a close replacement.

 

[gewf631]

Thanks to all for the suggestions.

I should have cleaned-off the wax before taking the photo - the shaft doesn't show any signs of peening, but I'll double-check.

Was worried about hitting the puller with too much force (the impact wrench) - worried about breaking the gear. Thanks to snaparxon, matt_i, and kbs2244, I'm pretty confident that a replacement is available, so I can attack-it with more vigor and not be too concerned if it breaks.

 

[Snaparxon]

I agree about the geometry, but not really a way to get the jaws close to the shaft. Furthermore, I can't believe that force on the outside of the gear, would impact the gear's hub (that's a pretty hefty piece of metal)

Some of the pulling force can get lost in the flex of the sprocket. that is why I said the closer the puller jaws are to the shaft the stronger the pull. I don't know what size chain runs on that sprocket but I have severely warped 8" 60 chain sprockets with a 10 ton puller. IIRC they are approx 3/8" thick sprocket

I think the "key" to getting your sprocket off is removing the key. Sounds like the key has moved which is a good thing, just need to move it the other way

 

[ez-duzit]

Early-on, I (stupidly) hammered the key back...

A potentially serious blunder as the shaft keyway likely ramps up and has caused the key to bind against the sprocket. Remove the key.

 

[gungatim]

you could drill a couple holes in the gear and run bolts in with nuts and use a harmonic balancer puller maybe? reweld the holes when done. or maybe even just weld a couple bolts right to the gear/hub and use a puller that way? I would be soaking with atf/acetone as well, get plenty into the set screw holes and keep working it back and forth.

 

[gewf631]

Some of the pulling force can get lost in the flex of the sprocket.

That makes more sense than the way I understood-it
Pulling on the outer 'lip' was transferring some of that force to the hub, effectively squeezing it tighter around the shaft.

Thanks!

 

[gewf631]

A potentially serious blunder as the shaft keyway likely ramps up and has caused the key to bind against the sprocket.

I didn't pound-it hard, but even if it did, I'm pulling the sprocket away from that ramped-up force, releasing that binding as the sprocket moves.

There's no real room behind the sprocket to get something down in there and push from the backside (no leverage either), so I'll be drilling the key as many have suggested.

Thanks!

 

[gewf631]

you could drill a couple holes in the gear and run bolts in with nuts and use a harmonic balancer puller maybe?

Not sure I could get a nut on the backside - there's just not much room, and if I went with a thinner nut, it might not be able to withstand the pulling force. Welding might work in conjunction, so if drilling the key doesn't work, that'll be my next step.

Thanks again to all for your suggestions.

 

[lis2323]

I’m in my shop right now and was looking at my puller board. You would prob require something similar to this one.

 

[Mgdoug3]

Torch off the gear, split the hub then pull it off. Order a weld on sprocket and hub. It looks like 40 chain. Any farm store should have those in stock.

 

[gewf631]

I’m in my shop right now and was looking at my puller board. You would prob require something similar to this one.

Yea, that would be great, but I could purchase a new snowblower for less than those pullers

 

[lis2323]

Yea, that would be great, but I could purchase a new snowblower for less than those pullers

You’re more than welcome to borrow mine but buying the set would be cheaper than gas for the trip. [emoji23]

 

[DieselNut88]

More heat. Make it cherry, then pull. Continue to heat as you pull.

 

[EdT]

Drill and tap two 5/16 " holes diametrically opposed into the hub of the sprocket. Make a bar about 3/8"/1/2" thick by 1 1/2" wide by as long as the hub is wide. In the center of the flat face, tap a 1/2" hole and two 5/16 clearance holes spaced the same as the tapped holes in the hub. Grind a rough point on a 1/2" bolt that fits the 1/2' Tapped hole in the bar. Bolt the bar loosely to the hub with two 5/16" bolts. Screw the 1/2" bolt in allowing the pint to center up on the center drill hole in the end of the shaft. Tighten the two 5/16 bolts 'til the bar is tight to the hub. Tighten the 1/2" bolt enough to put some load on the set up. Rap the end of the 1/2" bolt with a hammer. Snug up the 1/2" bolt and repeat 'til the sprocket comes off. Took me about as long to write that as it would take to do it if you have the material and the tools at hand.

 

[gewf631]

Drill and tap two holes...
Took me about as long to write that as it would take to do it if you have the material and the tools at hand.

Thanks for the suggestion. In my mind, drilling the hub would remove so much material that it might be prone to failure. No clearance behind for a through bolt. Besides, it's at the end of a 36" tractor-mounted snowblower, so not that easy to setup for my drill press (have to be really steady with a hand drill to get a good hole for tapping).

 

[Tracs]

I have rebuilt 2 of these snowthrowers. I would not hesitate to destroy that sprocket to get it off. Infact many people replace the sprocket with a smaller one for more auger speed. I seem to think that the stock one is 41 tooth and they like to replace it with a 32-34 tooth 1" bore 50 pitch chain.

I have removed all set screws and locking collars and driven the shaft itself sideways out of the sprocket. Takes heat and a whole lot of hammering or a puller and impact. The sprocket can be replaced for $20 or so.

 

[gewf631]

I have rebuilt 2 of these snowthrowers.
The sprocket can be replaced for $20 or so.

Thanks Tracs If you don't mind, I might PM you with a question

I've broken my puller twice now, so hope to attack it like a madman this weekend. Don't have access to Oxy/Acet, but have several extra disks for my angle grinder, so if it doesn't come off one way, it WILL come off another.

 

[gewf631]

SUCCESS

Thanks again to everyone for the excellent suggestions. Ended-up with just brute force (impact wrench on the puller). Bent the sprocket, but thanks to several suggestions, I've already got another one on order (and some new chain)
For the astute, don't worry, the bolts holding the carrier are just temporary