What diameter should I make for this press fit?

[phantomcow2]

I am boring out a cast iron bearing block to permanently press fit two 32mmOD bearings. Right now I have the OD of the bored area to 31.95mm, chucked on my lathe still. I am hesitant to do any more machining at this point without some guidance of how much I should leave on. Does anybody have any advice?

I am not sure whether this should be under this forum, or the general metalworking, so I will be posting in both.

[NC Cams]

Be careful with fitting bearings - it is possible to press them in and take up ALL the internal cleareance. A decent expanation of fits can be found here:

http://www.jp.nsk.com/app01/en/catal...gi?ec=bearings
Get the NSK E1102 catalog for starters

Press fits calcs for bushings here:
http://www.eng-tips.com/faqs.cfm?fid=1230

SWAG's sometimes work.

My business partner used to do it that way - until he messed up a bunch of high buck ball screw bearings by listening to an "expert machinist" who said "put em in at a thou press, this ain't rocket science".

When the bearings wouldn't turn, he then called me and I used the above table to calc the fit which he followed and the machine worked thereafter.

I was still an "a-hole" in the mind of his "expert machinist" but the book-learned, rocket science stuff at least worked.

No time or interest in calculating the fit the right way, use loctite and glue them in....

[NC Cams]

Be careful with fitting bearings - it is possible to press them in and take up ALL the internal cleareance. A decent expanation of fits can be found here:

http://www.jp.nsk.com/app01/en/catal...gi?ec=bearings
Get the NSK E1102 catalog for starters

Press fits calcs for bushings here:
http://www.eng-tips.com/faqs.cfm?fid=1230

SWAG's sometimes work.

My business partner used to do it that way - until he messed up a bunch of high buck ball screw bearings by listening to an "expert machinist" who said "put em in at a thou press, this ain't rocket science".

When the bearings wouldn't turn, he then called me and I used the above table to calc the fit which he followed and the machine worked thereafter.

I was still an "a-hole" in the mind of his "expert machinist" but the book-learned, rocket science stuff at least worked.

No time or interest in calculating the fit the right way, use loctite and glue them in....