How do I get the bearings out of this?

[pgrbffParticipant @pgrbff]

Having spent quite a while removing the cast iron wheel and aluminium pulley I am left with this.

I need to get the bearings out and I guess I need to remove the shaft first. I assume I need a press for that, but is there any way of knowing which end to press out? To keep the pulley aligned with the motor pulley, and the bottom wheel aligned with the top bandsaw wheel the shaft will need to be put back in the same position. Is it possible that it is somehow seated on something inside the casting?

Not sure where to start.

[pgrbffParticipant @pgrbff]

[SteviegtrParticipant @steviegtr]

1st off i would try to remove the silver cover in pic 1. This may reveal something. Otherwise it will need to be be pressed from one side. Also look for a circlip in the route of the bearing in pic 3.

Steve.

[Howard LewisParticipant @howardlewis46836]

The three grubscrews are either dutch keys, or clamp screws for a taperlock type fitting.

They should be completely removed. It may then be possible to remove the shaft from that end.

The bearing at the other end could then be removed using a suitably sized dolly, working from the flange end.

Then turn end for end and drive out the other bearing, if it did come out with the shaft.

Howard

[Nicholas FarrParticipant @nicholasfarr14254]

Hi pgrbff, I would think the bearing under the cover plate will be the one that sets the position of the shaft and it will probably have to be pressed out from the end that you can see the other bearing. That bearing is likely to stay in the housing and can be removed once the shaft is out, I doubt that is a very tight fit inside the housing, as I imagine it will have a little end float for expansion and contraction during use and temperature changes.

Regards Nick.

Edited By Nicholas Farr on 08/03/2021 15:16:16

[pgrbffParticipant @pgrbff]

I'm hoping there will be a circlip under the aluminium plate but all efforts to pry it off have failed so far. The holes are through holes and not threaded so I can't pull it off. There were 3 slotted machine screws holding it on. I'm trying to avoid drilling it to get better purchase.

[Brian WoodParticipant @brianwood45127]

Is it a screwed in cover and the three holes are there to fit a pin spanner?

Regards Brian

[Swarf MakerParticipant @swarfmaker85383]

It has to be simple. The disc with three holes is likely there to retain the bearing in the housing. Tap the far end of the shaft with a copper mallet and the shaft will likely exit, bringing the bearing and that ring with it. once out and clear of the housing the other bearing can be removed from the opposite end by judicious use of a drift through the housing. Do the first exploratory taps and see what starts to move to confirm.

[Tom SheppardParticipant @tomsheppard60052]

The narrow end of the assembly has a circlip which is to prevent the shaft being pushed through the wide end. Remove it and the shaft goes thataway. Detach the cover at the wide end to ensure there is no increased diameter behind it.

[Nicholas FarrParticipant @nicholasfarr14254]

Hi pgrbff, you could try putting a couple of snug fitting pins into two of those holes in that plate, but make sure they are no deeper in than the thickness of the plate and then get a pry bar or just a suitable length piece of bar and use it as a lever between the two pins and see if it will turn, squirt a bit of penetrating oil round the joint to help free it up and you may be able to wiggle it out.

Regards Nick.

[not done it yetParticipant @notdoneityet]

First question might be why does it need to come apart?

One end of that shaft looks to be of larger diameter than the other (close to the bearing) in the pic. Is that so? If it is, it will be clear that it is retaning that bearing against a shoulder on the shaft and will not pass through the bearing from that end.

[David CauntParticipant @davidcaunt67674]

If the arrow is pointing at a circlip then that would be the way forward.

[Nigel Graham 2Participant @nigelgraham2]

It does look like a circlip, and one nicely accessible to circlip pliers, at that!

If you have to remove the pulley too, the shiny bit looks like a Taper-loc hub to me – but if so it will have a tell-tale slot that allows it to close onto the shaft, may have a key-way, and normally has two grub-screws for grip. The third hole is for removing it, using a screw. I forget off-hand the methods for removing and refitting those hubs, but it is very simple, using only the appropriate Allen key.

I would guess that the shaft has at least one shoulder on it so the components can be fitted in their proper places.

[pgrbffParticipant @pgrbff]

Posted by Brian Wood on 08/03/2021 17:23:23:

Is it a screwed in cover and the three holes are there to fit a pin spanner?

Regards Brian

No pin spanner. Just three holes that had machine screws in them to hold the plate on.

 

 

Edited By pgrbff on 10/03/2021 09:00:05

[pgrbffParticipant @pgrbff]

Posted by David Caunt on 08/03/2021 20:42:42:

If the arrow is pointing at a circlip then that would be the way forward.

No circlips either end.

[pgrbffParticipant @pgrbff]

Posted by Nigel Graham 2 on 08/03/2021 22:21:48:

It does look like a circlip, and one nicely accessible to circlip pliers, at that!

If you have to remove the pulley too, the shiny bit looks like a Taper-loc hub to me – but if so it will have a tell-tale slot that allows it to close onto the shaft, may have a key-way, and normally has two grub-screws for grip. The third hole is for removing it, using a screw. I forget off-hand the methods for removing and refitting those hubs, but it is very simple, using only the appropriate Allen key.

I would guess that the shaft has at least one shoulder on it so the components can be fitted in their proper places.

The shaft under the pulley is very slightly tapered 1mm over 42mm, but no key-way or slot. Pulley is a simple press fit, with no grub screws or other means to stop it turning other than the taper.

[pgrbffParticipant @pgrbff]

I guess I'm going to have to find someone with a hydraulic press. There are no circlips. I'm not sure how I'm supposed to know which end to push it out from but maybe it doesn't matter. I have measured as best I can how far the shafts protrude from each end.

[HopperParticipant @hopper]

If you push it the wrong way with 20 tons of hydraulic pressure you could burst the whole thing asunder.

Instead, support the housing on two block of wood and firmly hit the end of the shaft with a heavy hammer and brass drift – or piece of wood. Use suitable restraint of course and check frequently if the large lower bearing is moving out of the housing, or if the shaft is moving in the upper bearing.

Hit it on the small end where the smaller bearing is. Usually that type of set up will go in from the large end and come back out the large end. The small bearing will probably stay where it is, up against a shoulder, and the larger bearing should come out with the spindle. Then you can knock the smaller bearing out.

Heating the body with a torch will reduce the force needed to move the bearings.

 

Edited By Hopper on 10/03/2021 10:00:13

[Nicholas FarrParticipant @nicholasfarr14254]

Hi pgrbff, more or less as Hopper says, it is likely that the inner race of both bearings will be against a shoulder on the shaft and one bearing will be locked in the housing by the cover plate and the other end will have room the float each way, so when pressing you may see the bearing on the end you are pressing, move slightly further into the housing until the outer race reaches a shoulder inside the housing. It shouldn't take an awful lot of pressure to press it out though, so if you decide to press it one way and does not seem to move, then stop and try it the other way. Personally, I would try pressing the short end of the shaft.

Regards Nick.

[RedsetterParticipant @redsetter]

Pgrbff – Why the overwhelming urge to take the bearings out anyway? Are they obviously worn or noisy? If not, they are probably best left alone. Remember you will have to put them back in correctly and without without damaging them. Assuming you want the machine to work again, of course.

[pgrbffParticipant @pgrbff]

No overwhelming urge.

I haven't run the saw so to be honest I don't know how they are. The bearings in the top wheel were quite rough when I took them out. As I have the saw apart I think it prudent to swap out the bearings rather than put it back together and then discover they need changing. I have very poor/difficult access to my workshop over grass. The saw weighed around 250 kg so I dismantled it to get it home.

I was going to replace the bearings with open ones like original but several people on here suggested I replace them with sealed.

[Dave HalfordParticipant @davehalford22513]

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.

[pgrbffParticipant @pgrbff]

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!

[not done it yetParticipant @notdoneityet]

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 HalfordParticipant @davehalford22513]

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.

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