"Tom" wrote in message
.. .

Well it's been in service here since 1987 so I'd imagine they are
failing from normal wear. I have just rebuilt the machine ways with
new linear shafting and bearings. No flanges per se as it uses plate
mounted wheels. The bit of vibration is requiring more wheel dressing
on some very friable open wheels.
The machine grinds the knives from wood chippers and the like.

Can sealed bearings fit where the ones with grease fittings were?

Dimensions are the same for open, sealed and shielded bearings. I
would suggest shielded bearings unless you have a pretty severe
contamination issue. Shielded are cheaper than sealed, more readily
available and do a pretty good job of sealing out dust, dirt etc but
does not work for water. Contact seals create drag and limits your
speed (but probably is not a problem on 1800 rpm motor of this size).
If you need a better seal than the shields provide NTN makes a non
contact seal (add LLB to the basic bearing number) which provides
better sealing than the shield but still does not contact the raceway.
I'd also look for bearings lubricated with Exxon PolyRex EM grease -
pretty much the new standard for electric motor manufacturers. Be sure
to press the new bearings on the shaft using the inner race if you
don't have a bearing heater to prevent brinnelling and shortening the
life. Good luck - let us know if you have any further questions.

Iset my bearings on a 100w light bulb for a little while to expand them a
little and warm the grease.