Thread: Orden TC grinder

Have you tried looking up the bearing and seeing how much interferance it is designed to be mounted with? That way you can get an idea of the force thats holding it in place. That said, I reckon youve got a snowflakes chance of getting it off and not damaging the bearing. Is the bearing second hand? It might not be at ABEC7 specs anymore anyway.

hmmm would dipping the shaft end in dry ice help? If you can get dry ice that is... With a hair dryer on the bearing...

Also it is a mm Fafnir, so a deep groove and not an angular contact....

The only thing I can think of is a 3 jaw bearing puller on the outer race, very gently and as soon as there is a gap between shoulder and bearing that is big enough, slip in something that will pull on the inner ring.

Michael

Originally Posted by scottyd

Have you tried looking up the bearing and seeing how much interferance it is designed to be mounted with? That way you can get an idea of the force thats holding it in place. That said, I reckon youve got a snowflakes chance of getting it off and not damaging the bearing. Is the bearing second hand? It might not be at ABEC7 specs anymore anyway.

It is very second hand, and there's every chance the only spec it meets is PR (pretty ropey). But until I know that I will proceed with caution. Good idea on the fit, will have a dig..... Ok, if I'm reading the table right it could have up to about 6 microns of interference. How much force would that be? My gut feeling is any interference could be enough to do damage.

Originally Posted by .RC.

hmmm would dipping the shaft end in dry ice help? If you can get dry ice that is... With a hair dryer on the bearing...

Also it is a mm Fafnir, so a deep groove and not an angular contact....

Interesting. The documentation I found was confusing in that this bearing doesn't seem to conform to their nomenclature. It has the WI which means angular contact, but not the prefix number which gives the contact angle. See attached. They do appear to be AC because one shoulder is higher than the other. Must be way obsolete.

Not sure how well heat would transfer through the balls to the inner race. Any chance of cooking the cage? Looks like phenolic. That's pretty heat-proof right?

Originally Posted by Michael G

The only thing I can think of is a 3 jaw bearing puller on the outer race, very gently and as soon as there is a gap between shoulder and bearing that is big enough, slip in something that will pull on the inner ring.

Michael

Maybe in combination with thermal persuasion.... ?

Looking at the picture it appears to be a through bore,why cant you just knock the other bearing out with a drift.

Originally Posted by pipeclay

Looking at the picture it appears to be a through bore,why cant you just knock the other bearing out with a drift.

It's the bearing on the shaft that is the problem, not the bearing in the bore.

Michael

Would this type of puller be applicable? I think one side is flat, and that would go against the bearing?

Pipeclay, the makers have provided holes for punches to extract that bearing from the housing, so that shouldn't be a problem. As MG says the shaft is the issue. And I believe it's Not Done to apply force through balls.

Originally Posted by Bryan

It is very second hand, and there's every chance the only spec it meets is PR (pretty ropey). But until I know that I will proceed with caution. Good idea on the fit, will have a dig..... Ok, if I'm reading the table right it could have up to about 6 microns of interference. How much force would that be? My gut feeling is any interference could be enough to do damage.

Bearings can be designed to be put into place with interferance fits or with certain loads placed upon them. This is why preloading the bearings in a car's wheel bearing is so important, that last final squish is what pushes or stretches the bearing components into their intended fit. The designer of your grinder would have specified the bearing, then specified the shaft interferance to suit the manufacturers recommendations, that way the bearing is spot on when it goes on the shaft.

I dont know how much force 6 microns will yeild, but ive pushed one on that had 4 microns and it required a press. I would say yours is tight enough that a hammer will not do, but others may know more conclusively than I.

If the bearing is knackered, just get it off and replace it. No point going to all this trouble just to look after a rooted bearing. Id replace it and contemplate a lower spec bearing, but it depends on your needs. Having seen the for sale thread where you picked this machine up, Id hardly suggest you can justify the mega price of an ABEC 7 spec replacement...Id love to know the price, I bet its really funny.

Mill away sections of the shoulder to enable access for a pin punch?

Dean

Originally Posted by Bryan

Would this type of puller be applicable? I think one side is flat, and that would go against the bearing?

That's the sort of puller I was thinking you needed once you can get it in. I think the least damage will be done to the bearing if steady pressure is applied.

Originally Posted by Oldneweng

Mill away sections of the shoulder to enable access for a pin punch?

Dean, Bryan is in a Shaper only household. While that thought is attractive as soon as you remove some material you also run the risk of throwing the shaft out of balance. While I would not dismiss it out of hand I would be approaching with caution.

Michael

Would I be completely crazy to think that the dynamic load a bearing can take is higher than its static load.. so if you were going to pull on the outer race would it make any difference to make it such that the shaft turning?

(I have an excuse if this idea is sillier than my norm. I'm on the sick list lol)

Stuart

Originally Posted by Bryan

Interesting. The documentation I found was confusing in that this bearing doesn't seem to conform to their nomenclature. It has the WI which means angular contact, but not the prefix number which gives the contact angle. See attached. They do appear to be AC because one shoulder is higher than the other. Must be way obsolete.

Should not trust my memory should I.... I saw the 2 missing and had some brain thought that 2 meant angular contact..

This the page for the SKF version of that bearing (tolerances to one side). The static load is around the 2 tonne mark. Now without being a bearing expert (far from it) I would suggest that provided the force to remove it did not exceed this (and no shocks were involved) it should not damage the bearing. (Static load is in a radial direction and the removal force is axial but as it is angular contact will that really make a difference?)

7207 bearing (Large).jpg

Michael

It shouldn't be that tight on the shaft,just push or knock it off,if the problem is in that bearing then it doesn't matter.