Tolerance/fit question

I am turning a ballscrew end down, to fit a 6mm dia bearing. The bearing
will be ABEC7, which has a hole tolerance of 0 to -4 microns.
So far, so good. But how big should I make the shaft?
It is 6.000 mm now (yes, to +/-1 micron :o), but normally I'd turn it
down a bit more; I don't want to have to heat the bearing to get it
on/off, a sort of medium interference fit will do.
I have been googling, and there are tables of tolerances, and pages with
recommended fits, but I haven't seen one page which actually recommends
an actual size or even what a normal type of fit is in terms of
tolerances - maybe my google-fu, or perhaps my engineering-fu, or both,
is weak today.
Thanks,
Peter Fairbrother
Reply to
Peter Fairbrother
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You don't want to reduce it below 6.000mm. Doing so brings the risk of a slightly sloppy fit. With the bearing tolerance and the measured shaft size,
press on at that sort of fit, but will be a hand (clean handkerchief for
that temperature.
regards
Mark Rand
Reply to
Mark Rand
OK, I'll go with that for now, just round off the end edge and cut the slot for the circlip. Thanks.
I was a bit worried, it took me hours to get the ballscrew chucked with sufficiently concentricity and [parallelness of the axes of rotation and ballscrew, whatever that's called], and I didn't want to take it out of the lathe and disturb the setup.
On reflection that worry was a bit pointless, as I am using carbide paper for the final finishing-to-size, and I could just rechuck it any-old-how and hold the paper in my fingers ..
ah well, thanks anyway.
-- Peter Fairbrother
Reply to
Peter Fairbrother

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