How do I get the bearings out of this?

[pgrbffParticipant @pgrbff]

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?

[pgrbffParticipant @pgrbff]

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 R2Participant @adrianr2]

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.

[pgrbffParticipant @pgrbff]

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 R2Participant @adrianr2]

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 HancockParticipant @jhancock95746]

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 CauntParticipant @davidcaunt67674]

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

The idea is good though.

[pgrbffParticipant @pgrbff]

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 HalfordParticipant @davehalford22513]

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 CauntParticipant @davidcaunt67674]

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 FarrParticipant @nicholasfarr14254]

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

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

[pgrbffParticipant @pgrbff]

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.

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 TaylorParticipant @mauricetaylor82093]

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 LewisParticipant @howardlewis46836]

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

[HopperParticipant @hopper]

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

Field Service 101.

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

[pgrbffParticipant @pgrbff]

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

Thank you all for you help.

[J HancockParticipant @jhancock95746]

Just out of interest.

Did you note at what 'pressure' it broke free ?

[pgrbffParticipant @pgrbff]

Unfortunately not. I was concentrating hard on part in case it didn't move.

It felt fairly high. It was a large press in a car workshop and I had to pump a few times.

Not looking forward to putting the bearings back.

[Martin King 2Participant @martinking2]

Put the bearings in the freezer before putting them back, works for me!

Cheers Martin

[pgrbffParticipant @pgrbff]

Posted by Martin King 2 on 21/03/2021 09:50:11:

Put the bearings in the freezer before putting them back, works for me!

Cheers Martin

I used to do that when replacing bearings in R/C model engines.

[Nicholas FarrParticipant @nicholasfarr14254]

Hi pgrbff, you will probably need the use of a press again, I wouldn't bother about freezing the bearings because if anything that will make them tighter to fit onto the shaft. First of all, press the fixed end bearing onto the shaft using a suitable tube or a clearance hole in a piece of thickish plate, then mount the shaft and bearing into the housing and put it on the press with the tube or plate on the bars of the press. Then lower the other bearing onto the shaft squarely and get the outer race to start into the housing, you will need another piece of tube and a plate if you wish, which is a clearance fit over the bearing journal and the plate a clearance fit inside the housing and the tube will have to be long enough to extend past the shaft end to allow the bearing to be pressed up the the shoulder on the shaft.

I've always found when pressing the second bearing in, is to press it a little way then release and turn the housing a quarter or a half turn and press a little further and then give it anther small turn and then press it home, this just helps to make things square and all lined up.

Regards Nick.

[pgrbffParticipant @pgrbff]

Posted by Nicholas Farr on 21/03/2021 13:08:46:

Hi pgrbff, you will probably need the use of a press again, I wouldn't bother about freezing the bearings because if anything that will make them tighter to fit onto the shaft. First of all, press the fixed end bearing onto the shaft using a suitable tube or a clearance hole in a piece of thickish plate, then mount the shaft and bearing into the housing and put it on the press with the tube or plate on the bars of the press. Then lower the other bearing onto the shaft squarely and get the outer race to start into the housing, you will need another piece of tube and a plate if you wish, which is a clearance fit over the bearing journal and the plate a clearance fit inside the housing and the tube will have to be long enough to extend past the shaft end to allow the bearing to be pressed up the the shoulder on the shaft.

I've always found when pressing the second bearing in, is to press it a little way then release and turn the housing a quarter or a half turn and press a little further and then give it anther small turn and then press it home, this just helps to make things square and all lined up.

Regards Nick.

Someone suggested I should use the old bearings to press in the new?

Edited By pgrbff on 21/03/2021 13:14:05

[Howard LewisParticipant @howardlewis46836]

Good Idea! It may be worth stripping the old bearing. A quick grind round the OD of the outer race will prevent it sticking should it enter the housing.

The old bearing will put the load onto the outer race, avoiding damage to the balls and the inner race.

The old inner race can then be used to support the new inner race while the shaft is pressed in, avoiding loading the outer.

Howard

[Nick WheelerParticipant @nickwheeler]

Posted by pgrbff on 21/03/2021 13:13:39:

Someone suggested I should use the old bearings to press in the new?

You need a suitably sized spacer to press against, and the old bearing is already close to being the right size. Once you've reduced the outside diameter so it's no longer a press fit, it will be the right size.

[Nicholas FarrParticipant @nicholasfarr14254]

Hi pgrbff, yes yon can use your old bearings, but just make sure the inner race isn't press onto a little bit on the bearing journal that may be sticking out past your new bearings. Of course you could use a die grinder ( or a Dremel type tool) just to make your old inner race a bit bigger a little way in on the side used next to new bearing, just make sure every thing is clean, as you don't want grinding dust in your new bearing.

Regards Nick.

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