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How do I get the bearings out of this?

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Dave Halford10/03/2021 11:27:23
2536 forum posts
24 photos

If both bearings have a step down on the shaft diameter in front of them then pressing either way should do. One end the shaft will press in, the other the bearing will press out on the shaft. If you have a vice that opens far enough to take the whole shaft I would try that first as you know how hard you are pushing the shaft. You get no feed back from a press till something breaks.

pgrbff10/03/2021 11:56:52
261 forum posts
31 photos

Both ends of the shaft are the same size as the bore of the bearing or taper down so I am hoping that it can be pressed either way. The bearings are identical, at least in diameter and bore.

There is a grease point only at one end of the hub, I'm assuming the shaft floats on the two bearings and grease passes from one end of the hub to the other alongside the shaft.

It just seems odd that there is no step or register to ensure the shaft is in the right position relative to the hub once you replace it. If not the pulley and the motor pulley will be out of alignment, as will the 2 cast iron saw blade pulleys.

So much easier to work with wood!

bottom hub showing kauffer.jpg

not done it yet10/03/2021 12:18:50
7517 forum posts
20 photos

Forgive me if I am being stupid, but the first pic on this thread appears to clear show a shoulder close to that screwed on cover. I suggest you you check again.

Dave Halford10/03/2021 12:24:58
2536 forum posts
24 photos

The Shaft is probably stepped at both ends inside the hub so that shaft will not float. So if you cut a hole in a piece of wood big enough for the outer race to pass through you might be able to knock the shaft through from the other end with a copper, rawhide or lead hammer. Use a piece aluminium or wood dowel to knock it through the bearing.

Do not use a steel hammer or steel drift on the shaft under any circumstances.

pgrbff10/03/2021 12:28:45
261 forum posts
31 photos
Posted by not done it yet on 10/03/2021 12:18:50:

Forgive me if I am being stupid, but the first pic on this thread appears to clear show a shoulder close to that screwed on cover. I suggest you you check again.

There is a shoulder. To the left of the shoulder, the shaft tapers down, to the right of the shoulder it is the same diameter as the bore of the bearing. I'm not sure what I am missing?

pgrbff10/03/2021 12:31:34
261 forum posts
31 photos
Posted by Dave Halford on 10/03/2021 12:24:58:

The Shaft is probably stepped at both ends inside the hub so that shaft will not float. So if you cut a hole in a piece of wood big enough for the outer race to pass through you might be able to knock the shaft through from the other end with a copper, rawhide or lead hammer. Use a piece aluminium or wood dowel to knock it through the bearing.

Do not use a steel hammer or steel drift on the shaft under any circumstances.

I have tried using a steel club hammer using a dense piece of hardwood as a drift, more or less the same diameter as the shaft. It won't budge. Do not have large copper or lead hammer, unfortunately.

Adrian R210/03/2021 13:59:32
196 forum posts
5 photos

If no joy by bedtime, put it in the freezer overnight then get out in the morning and give it another thwack, less destructive than heating and you may get lucky. When it comes to freeing things off one good hit is better than a lot of little taps so plan ahead and have a way to support it so you can thump confidently. I'm **guessing** that it will either be a plain shaft with a tubular spacer between bearings, or have a larger diameter internal section with shoulders and maybe some shims, and will come apart from either end.

That said, how much do you intend to use this saw once rebuilt? You now have good access to the bearings so could flush them out, relubricate and see how they run. May be good enough.

pgrbff10/03/2021 14:07:39
261 forum posts
31 photos
Posted by Adrian R2 on 10/03/2021 13:59:32:

If no joy by bedtime, put it in the freezer overnight then get out in the morning and give it another thwack, less destructive than heating and you may get lucky. When it comes to freeing things off one good hit is better than a lot of little taps so plan ahead and have a way to support it so you can thump confidently. I'm **guessing** that it will either be a plain shaft with a tubular spacer between bearings, or have a larger diameter internal section with shoulders and maybe some shims, and will come apart from either end.

That said, how much do you intend to use this saw once rebuilt? You now have good access to the bearings so could flush them out, relubricate and see how they run. May be good enough.

 

I paid around £6 each for the two top bearings, SKF 6205's. These are 10mm wider so I'm not expecting to pay much more. As I said I originally planned to replace them with open bearings but virtually everyone said used sealed. I'm a woodworker and the saw has been bought to use, so it will see some hours.

I agree the shaft probably is wider in the middle, let's hope so anyway.

Edited By pgrbff on 10/03/2021 14:08:21

Adrian R210/03/2021 14:21:01
196 forum posts
5 photos

Less convinced about my freezer idea now. The shaft will need to move on at least one and maybe both the bearing inner races, cooling the whole lot won't do much there. Perhaps put it the freezer and then allow to warm up in the sun or on top of a radiator, some differential effect might occur to loosen it.

J Hancock10/03/2021 14:23:45
869 forum posts

Option Two, a blind flange with 4 holes on same PCD as those shown.

Four lengths of 12mm studding , tight as you can pull them up , heat the body,, hot as you can , hit the flange with at least 2lb hammer , hard, tighten studs again, repeat, etc.

David Caunt10/03/2021 14:47:14
avatar
110 forum posts
40 photos

Are the holes on the small end really 12mm? If the bearing is 52mm they look less than that.

The idea is good though.

pgrbff10/03/2021 14:58:42
261 forum posts
31 photos

Every thread on this Italian bandsaw is BSW. They're 1/4", 5/8 long round head slotted.

It's costing me a mall fortune in taps and dies from the UK as a lot of the threads are in very poor condition.

Dave Halford10/03/2021 14:59:44
2536 forum posts
24 photos
Posted by J Hancock on 10/03/2021 14:23:45:

Option Two, a blind flange with 4 holes on same PCD as those shown.

Four lengths of 12mm studding , tight as you can pull them up , heat the body,, hot as you can , hit the flange with at least 2lb hammer , hard, tighten studs again, repeat, etc.

The flange is cast iron, guess what hitting it hard with a 2lb hammer will do?

David Caunt10/03/2021 15:48:30
avatar
110 forum posts
40 photos

Dave,

I believe the theory was to make a blank plate with 4 holes at the pitch diameter of the holes on the small end of the casting and then use the manufactured studs ( to what ever thread they are). Then use these to apply pressure to the manufactured plate which will push on the end of the shaft. Then rest the large end on a good support and hit the new plate which has been pulled up tight to the end of the shaft. It isn't quite the same as hitting the flange with a large hammer.

It is either that or as has been said just clean it up and refit it.

Dave

Edited By David Caunt on 10/03/2021 15:49:00

Nicholas Farr10/03/2021 16:00:07
avatar
3988 forum posts
1799 photos

Hi pgrbff, I can't guarantee it, but I image the cross section sketch below is what your bearing assemble arrangement looks like.

bearing assembly001.jpg

It is quite likely that the position of the shaft is fixed by the plate at the flanged end and the plate will nip the bearing in the correct place and there may be a small amount of end float on the outer race of the other bearing. it is likely that the bearings will be a press fit onto the shaft.

Regards Nick.

P.S. The sketch is probably nowhere near to scale, but it should give you the idea.

Edited By Nicholas Farr on 10/03/2021 16:04:08

pgrbff10/03/2021 16:28:34
261 forum posts
31 photos
Posted by Nicholas Farr on 10/03/2021 16:00:07:

Hi pgrbff, I can't guarantee it, but I image the cross section sketch below is what your bearing assemble arrangement looks like.

bearing assembly001.jpg

It is quite likely that the position of the shaft is fixed by the plate at the flanged end and the plate will nip the bearing in the correct place and there may be a small amount of end float on the outer race of the other bearing. it is likely that the bearings will be a press fit onto the shaft.

Regards Nick.

P.S. The sketch is probably nowhere near to scale, but it should give you the idea.

Edited By Nicholas Farr on 10/03/2021 16:04:08

Many thanks for taking the time to do the sketch. That is the conclusion I have come to, but I have little experience in these things. I have a friend with a press, he owns a motor workshop, and I'll have to try and get over to him. The trouble is lockdown prevents me to go to another province, Liguria, so I'll have to wait.

Maurice Taylor10/03/2021 18:41:46
275 forum posts
39 photos

Hi,

Have you got a 3 leg puller,you could use it to try to push the shaft out .This might work ,it might not but worth a try.

Maurice

Edited By Maurice Taylor on 10/03/2021 18:42:51

Howard Lewis10/03/2021 19:54:02
7227 forum posts
21 photos

Using a three leg puller on the flange could break it.

Pressing with the flange supported almost to the bore would be safer.

Once the shaft is out, you can either remove the bearing from it, and then use it to press out the other bearing, or turn up a dolly to do the job. (If possible large enough to press on the outer race. ).

Howard

Hopper11/03/2021 03:31:05
avatar
7881 forum posts
397 photos

Hammer and blocks of wood will get around the lockdown restrictions.

Field Service 101.

Edited By Hopper on 11/03/2021 03:32:11

pgrbff21/03/2021 08:03:40
261 forum posts
31 photos

Finally apart. Exactly as Nick suggested. Had to find someone with a press in the end.

Thank you all for you help.

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