press fit bearing

[firebird]

Hi

I am boring a hole in some 1/2 inch steel plate to accept a 50mm dia taper roller bearing. (Nice mix of imperial and metric there :big: :big: :big I am currently at the 49mm stage. What size should I take it to for a good press fit for the outer race. I am using an imperial Myford lathe so thou's will do me.

cheers

Rich

 

[tel]

Take about 1/32" depth out to the 50mm dead on, then sneak the rest out til it 'just won't fit' - if you've noted the dial setting for the 50mm it should be easy enough.

 

[mu38&Bg#]

Timken suggests .0002-.0009" interference for press fit, or .0004-.0011" clearance for a floating fit, or something in between for a transitional fit.

 

[firebird]

Hi

Thanks Tel, that's a good idea.

Thanks Greg, that's a lot less than I thought.

I fit loads of wheel bearings at work in the press but have never thought about how much difference in size there is. I guess if it were too tight the bearing would distort??

Cheers

Rich

 

[mu38&Bg#]

They distort if the hole you're putting them in isn't round. Tight fits are probably not a big a problem for rollers, but you can use up clearance built into a ball bearing if the fit is tight.

 

[Swede]

Obviously, heating the bore for the press will help tremendously. If in doubt, I'd lean towards the large end of the interference fit. So long as the outer race remains fixed, it should function as intended. You could always slip in a set screw to help it out if you think it's going to rotate on you, but a fit would have to be pretty sloppy for that to happen.

 

[kvom]

Green loctite will keep it secure if the fit is a bit loose.

 

[Brian Rupnow]

I would never use a set screw to retain a bearing race. If its tightened enough to retain the bearing, then its tight enough to distort the outer race and lead to early bearing failure. Like Kvom says---go light on the press fit and use a bit of Loctite.

 

[firebird]

Hi

Thanks for the info, I will be completing the boring this weekend, slowly does it me thinks. I'll get some green loctite as well just to make sure.

Cheers

Rich