Advice needed on a vintage chain sprocket

[Dunsey]

Hi Folks, I am a new member from NI, who badly needs your assistance.

I am struggling to maintain some very old winches on an island in Strangford Lough, which is part of a very small farm.
Need all the help I can get, as all the parts are probably pre WW2.

I need to remove and reposition a chain sprocket on a DC motor that drives a winch used to haul boats .

I have managed to remove the three grub screws from the sprocket ( One on the key way and two on the face ) but now need to pull the unit.
Q. Been soaking it in lube, but should I force lube down the threaded way with another grub screw?
Do I then pull it with the key in position, as I cannot see how else it was put on?

Any suggestions please.

I attach some photos.

Thank you.

 

[MBfreak]

I worked on some electric motors on a FUTURLINER. Gear reduction and output hsft had chain sprockets. Mfr around 1936.
Removing the sprockets was difficult, until I found out that there were two grub screws! The bottom one was very hard to see.
The outer one was to secure the inner one, which pressed on the key.
Removed both used 50% ATF /50 % Acetone magic fluid . Let it soak for 10 minutes and then all sprockets came off quite easy.

Ola

 

[MushCreek]

Yes, make sure all of the screws are out. I don't know if it's an optical illusion, but the shaft looks very slightly mushroomed on the end. Clean up the exposed end of the shaft so once it starts to move it doesn't have to drag over all of that rust. A few licks with a file will determine whether it is mushroomed, and then you can dress that off.

 

[Dunsey]

Thank you both and f you will go back and make sure I have all the grub screws outand Clean it all up
Thanks for the advice which is gratefully accepted

 

[Dunsey]

Sorry auto correct has made a bad typo that should read I will go back and check.... definitely not what was posted above very sorry

 

[4x4Petr]

I have worked on older belt drive sheaves that have a somewhat hidden taper lock. You need to see if there are any "unused" threaded holes in it, thread in a couple of appropriate bolts to disengage the taper lock. Sometimes even the grub screws are used for this. It usually is fairly easy to see but once in a while they can be weird like it's some kind of big secret. Good luck.

 

[OccupantRJ]

Look inside the holes in the face of the hub to see how it is threaded. This will be a clue. The hub may have been taper locked by driving it into place, and the threaded holes may be to remove the sprocket instead of holding it on. There are usually two sets of holes in American hubs, one set for install and one for removal. By looking into the holes you should be able to determine if the screws are used for retaining, or for removal. One half the wall of the hole may be threaded. One of yours may be for retention and the other for removal.

 

[TractorJeff]

Look inside the holes in the face of the hub to see how it is threaded. This will be a clue. The hub may have been taper locked by driving it into place, and the threaded holes may be to remove the sprocket instead of holding it on. There are usually two sets of holes in American hubs, one set for install and one for removal. By looking into the holes you should be able to determine if the screws are used for retaining, or for removal. One half the wall of the hole may be threaded. One of yours may be for retention and the other for removal.

Its been a long time since I have seen a hub like that and I agree with Occupant those maybe half threaded for a "Taper Lock". No matter what with a captured key like that, the sprocket will need to come over the key. I agree to dress the end of the shaft with a file to make life easier. I don't recommend pulling with those hub bolt holes. I would pull from the back side with a Good brand multiple jaw puller (OTC).

 

[BillK]

Take a brass punch or maybe even a large socket and see if you can get it to move back on the shaft towards the motor some. Once you get it moving it will probably come off pretty easy. If you use a three jaw puller what I have found works is to tighten up the puller as tight as you can and if it doesnt move smack the end of the puller with a hammer. Then tighten it some more and repeat.

If you can get hold of something like this tool they work even better and wont hurt the sprocket:

https://www.harborfreight.com/Bearing-Separator-and-Puller-Set-62593.html

 

[larry_g]

https://www.usarollerchain.com/1008-Taper-Lock-Bushing-p/1008-12mm-taper-bushing.htm

Above is a link to a taper lock bushing that is similar to the one you have. You may find that the threaded hole to push the taper apart is on the back side of the assembly. If it has no threaded hole to push it apart then check on the two faces to figure out which way the taper is and then drive the sprocket off of the taper. If you try to pull it against the taper you will succeed in tightening things up. With luck once the taper is separated the bushing will just pull off by hand.

I would also suggest that you google 'split taper bushing' or 'taper lock bushing' or 'taper lock hub' to learn a bit more. There are a few different forms of these but most work in a similar fashion.

lg
no neat sig line

 

[SGKent]

I have worked around sprockets and pulleys much of my life. The issue you have is that the elements have fused those two together. Use some real penetrating oil on it over night to convert the red rust to black rust, and that will reduce the friction between the two. That means you need something stronger than ATF and Acetone. Use Liquid Wrench or PB Blaster.

Find someone with a press and a bearing plate they can put behind the gear. Then you can use either a press or a good two finger bearing puller on the plate. Be 100% sure any grub screws are removed first. Try to stay away from drifts and punches but if you do use one make sure it is a brass one. Do NOT use a steel drift.

or

You can use one of many different pullers like the Kuko above with the bearing separator plate or even one of these if you can find one that fits right. Make sure what ever you use pulls on the hub and not on the teeth.

 

[larry_g]

I have worked around sprockets and pulleys much of my life. The issue you have is that the elements have fused those two together. Use some real penetrating oil on it over night to convert the red rust to black rust, and that will reduce the friction between the two. That means you need something stronger than ATF and Acetone. Use Liquid Wrench or PB Blaster.

Find someone with a press and a bearing plate they can put behind the gear. Then you can use either a press or a good two finger bearing puller on the plate. Be 100% sure any grub screws are removed first. Try to stay away from drifts and punches but if you do use one make sure it is a brass one. Do NOT use a steel drift.

or

You can use one of many different pullers like the Kuko above with the bearing separator plate or even one of these if you can find one that fits right. Make sure what ever you use pulls on the hub and not on the teeth.

I don't agree with the above considering that this most likely a tapered hub sprocket, and the two threaded holes on the face and the split line. If you confirm this is not a taper lock then the above is right on.

lg
no neat sig line

 

[ttpete]

Most of us in the US aren't familiar with grub screws. They're drilled half in the shaft and half in the sprocket and aren't much used here. That's just a straight shaft that uses a flat key. It should come right off with a puller. A little heat might help as well.

 

[John Timmins]

Here's a dirty stunt I learned the hard way...… when you remove the screw holding the key, make sure there isn't a SECOND set screw in that hole that is STILL holding the key in the keyway
Sometimes there's 2 screws in there !!!!

the 2 holes in the end are for the puller. you can screw some all-thread in those holes ahd work form there

You don't want to put too much heat on that motor shaft. I would get it nice and hot and melt some bees wax on that key. It will wick into the crevases. You can't get it too hot or the wax will burn off. Repeat the heat and melt a bit more wax.

It you get the puller tight, hit the end of the puller screw with a hammer.

I place a copper penny against the shaft where that center hole is machined the tighten the puller. Let us know how you make out !

 

[MattT]

I don't agree with the above considering that this most likely a tapered hub sprocket, and the two threaded holes on the face and the split line. If you confirm this is not a taper lock then the above is right on.

Yeah putting a puller on what may be a taper bushing is a very bad idea. A good look at the gearbox side face may yield further clues. A counterbore or tapped holes.

Another thing is the hole on the outside diameter at the front. That may be for unscrewing the sprocket halves?? Also check there isn't anything down in that hole.

Most of us in the US aren't familiar with grub screws. They're drilled half in the shaft and half in the sprocket and aren't much used here.

Grub screws in the UK are set screws in the US. What you're describing sounds like a dog point grub/set screw.

 

[nadogail]

A lot of years ago (maybe 60) I worked for an automotive machine shop who was also an engine re-builder.

One day I was using an OTC puller, a 3/4" drive ratchet trying to pull something from a shaft, nothing was budging. I rapped on the end of the puller screw with a 5lb single jack, a customer said to the shop owner "I'd fire anyone who beat on a puller"
My boss, the shop owner said "I will fire anyone who won't"
I left the puller under tension for a few minutes and we soon heard a loud pop, as the something broke loose.

Sometimes you are "Damned if you do and dammed if you don't"

Given enough force, time and some vibration, things just might move.

50 years later, at another job, I was asked to help disassemble a machine. The tech working on it was using a propane torch in an attempt to heat a gear to pull it from a shaft. Too little heat, I told him he needed some serious heat. He asked, how much? I rolled over the cart with the torch set, hooked the "Rose Bud" tip, fired it up and said "Orange is nice". that orange hot gear almost fell of the shaft.

Sometimes you just have to get serious.

 

[Dunsey]

Thank you all for your very helpful replies.
I am delighted to tell you the sprocket has pulled off and cleaned up and replaced in the correct position.
I would not have been able to do it without all your advice.

Many thanks.

(My bro -in laws hands)


Alisonx

 

[BillK]

 

[SGKent]

Good job.

FYI to others - lots of the things I have worked on have taper shafts. If you have the factory puller they work great but without it you have to use a split shell bearing puller or a tool designed for the hub size. ALL the taper shafts I have come across had a nut or bolt on the end of the shaft holding the hub onto the shaft so the hub was pushed down on the taper. I have never seen a taper shaft held on with a grub screw. That did not look like a taper shaft hub and I don't see why some people were so alarmed. A taper shaft needs pressure from the end to hold the taper shaft and hub together.

Taper shaft with key

View media item 94067
His sprocket and shaft has a spot to put it on a lathe but not a bolt or nut. It is not a taper shaft. Even if it was the procedure is the same but you should leave the nut or bolt on a ways to keep the hub from becoming a projectile when it releases. And yes, if someone had the correct factory puller they could have probably threaded it in to the hub. Also as stated, always file the end to rid of any burrs or mushrooms that may be present. A flat mill file will tell you quickly if any are present.

 

[ttpete]

That sprocket has been bushed down to fit the shaft and that's why the grub screws were used.

 

[larry_g]

Good job.

FYI to others - lots of the things I have worked on have taper shafts. If you have the factory puller they work great but without it you have to use a split shell bearing puller or a tool designed for the hub size. ALL the taper shafts I have come across had a nut or bolt on the end of the shaft holding the hub onto the shaft so the hub was pushed down on the taper.

His sprocket and shaft has a spot to put it on a lathe but not a bolt or nut. It is not a taper shaft.

In all the posts above I don't think anyone referred to a tapered shaft. All taper references were to a taper lock hub. After see it off it does seem to be a straight bush. I'd be curious to see the back side of that sprocket and know if the bushing is straight or tapered.

lg
no neat sig line

 

[SGKent]

I see an old straight shaft hub, nothing more. Not a taper shaft or taper lock hub. The hub bushing has no splits in it to pinch the shaft. Also I see the smooth area as machined. Maybe I am wrong but that is what I see.

example: