How do I get the bearing off the shaft cylander thing?

[Ives]

Got my new bearing for my bandsaw, and I measured wrong, so the inner diameter is 1mm too big. I should have taken it off to measure!! Anyway, I can't get it of this cylindrical thing it's on. It seems impossible, how do you get it off?

Also, when I spin it, it feels gritty or something inside, is that another sign it's bad and needs replacing?

Found a number on it in amongst the rust, it looks like 625 ZZ but it doesn't measure the same as what I've found that one to be on Simply Bearings or Ebay. I'm sure it measures 15 x 9 x 4 but that doesn't exist!!!!!!!!!!!!!!!!

 

[Teckel]

Can you get a bearing puller on it ??

 

[Ives]

Oh, I need a special tool to get it off?

 

[Teckel]

if it's a tight fit you will but maybe someone with better experience in this field than me might tell you better

 

[kirkpoore1]

Got a picture?

15 x 9 x 4? That's tiny. Or is that a 4 mm bore? There is such a bearing as a 634 ZZ, which is 16 x 4 (bore) x 5 (thickness). At 15 mm OD and 9 mm bore wouldn't leave much room for race thickness or ball diameter.

Kirk

 

[Racers]

Hi, Ives

They are a tightish fit, can you get the shaft its mounted on off?

If you can you can put it between the jaws of a vice and tap out the shaft using a rod/nail, then tap the shaft back into the bearing, when you have the right one.

Check the number with a magnfying glass

625 zz http://www.bearingoptions.co.uk/bearing ... -237-p.asp



Pete

 

[Eric The Viking]

Got my new bearing for my bandsaw, and I measured wrong, so the inner diameter is 1mm too big. I should have taken it off to measure!! Anyway, I can't get it of this cylindrical thing it's on. It seems impossible, how do you get it off?

Also, when I spin it, it feels gritty or something inside, is that another sign it's bad and needs replacing?

Found a number on it in amongst the rust, it looks like 625 ZZ but it doesn't measure the same as what I've found that one to be on Simply Bearings or Ebay. I'm sure it measures 15 x 9 x 4 but that doesn't exist!!!!!!!!!!!!!!!!

Go on, post us up a picture, with a ruler next to the bearing!

 

[Ives]

I'm pretty sure the measurements are 15 OD, 9 ID, 4 thick. But with the macro lens shot, the number looks like 625 2Z, not ZZ.

Here are some photos:

 

[Bradshaw Joinery]

http://simplybearings.co.uk/shop/advanc ... d84b1db9c9

from the picture with the tapeit does look like the bore is 5mm...

as said, you need a punch with a diameter of slightly less than 5mm, and drill a hole in a peice of wood for the spindle to sit in, and then tap the spindle through,

When putting the new one on dont tap the outer race, only the inner, so the bearing surface doesnt get damaged.

 

[mbartlett99]

In addition when you're putting the new one on put the shaft in the freezer for an hour , you can also gently warm the new bearing but I'm saying radiator not blowtorch. Looks like that shaft could do with a bit of a clean up as well.

 

[Tony Spear]

Maybe it's the angle it's been shot at, but the o/d looks well over 15mm. to me.

 

[Teckel]

The OD looks about 18mm to me.

 

[Ives]

It must be the angle, the OD is definitely 15. I'm confused about the ID though. I think maybe I'm measuring the wrong thing. There is a smaller diameter which is about 5mm, but it's inside the 9mm diameter which spins around with the shaft. I figured the part that spins must be a part of the shaft. But it if its 5mm ID, it fits with the measurements of the 6252 Z.

And thanks for that link, I was just putting a space between the last 5 and 2, that's how it looks on the bearing! Would it be better to get an RS one so it doesn't clog with sawdust?

 

[mbartlett99]

Is this what you're looking for; http://simplybearings.co.uk/shop/advanc ... Z&x=4&y=13

SKF are probably the best bearing manufacturer in the world, certainly the largest so going to RS will not be an improvement although you might try getting a fully sealed unit.

 

[Ives]

Is this what you're looking for; http://simplybearings.co.uk/shop/advanc ... Z&x=4&y=13

SKF are probably the best bearing manufacturer in the world, certainly the largest so going to RS will not be an improvement although you might try getting a fully sealed unit.

It's just that someone mentioned it's good to have the rubber seal, which I think is what the RS means, as it keeps the sawdust out.

 

[mbartlett99]

Ah - thought you meant going to RS Components. Whenever I've an issue like this my first action is to call up the bearing supplier with either the dimensions and duty or the part number and see if they can give me a more robust unit. Call up your nearest SKF dealer and see if they can supply a fully sealed unit, it would be best if you can give them the speed of the machine as well (rpm of the shaft).

 

[CHJ]

It's just that someone mentioned it's good to have the rubber seal, which I think is what the RS means, as it keeps the sawdust out.

Yes as long as you do not let the sawdust pack up around the bearing putting side pressure on the seals the rubber seals are normally a better fit on the inner race than the metal ones and prevent fine dust ingress better.

 

[CHJ]

Having said the above sooner or later you may well end up with something akin to this, using an airline blowgun to 'clean' the dust off rather than a vacuum cleaner can be counter productive in forcing the dust in.

I've yet to work out how come so much manages to pack itself in, I can only assume centrifugal forces combined with some measure of warm air movement from generated heat suck it passed the inner seal, I sometimes wonder if a plain dry lubed unsealed bearing may fare just as well.

Mind you looking closely at the rubber seals from the above bearing it is obvious that both the inner seal surfaces have been very severly abraded, presumably by the wood dust or associated grit particles.

 

[jimi43]

I think that this is the thrust bearing behind the guides (or one of them) isn't it Ives?

RPM is therefore unimportant...(unless something is seriously wrong with your setup!)

Jim

 

[Cheshirechappie]

The '2Z' on the bearing number is the usual bearing manufacturers' code for metal shielded bearings. If the code had been just 'Z', that would be shieded one side only, '2Z' or sometimes 'ZZ' means metal shielded both sides. An 'RS' code usually means rubber shields.

The shields are supposed to prevent ingress of foreign matter to the races. Clearly, they are not always totally effective!