1989 A1S mill spindle runout < 0.0002"

slow-poke

Ultra Member
I pulled the quill and spindle, repacked the Made in Germany SKF 7207BEP Angular contact bearings, and set the preload.

Runout was good before, but even a bit better now and really smooth, measured on a 5/8" end mill just below the collet at < 0.0002" not bad for a 35 year old mill.

When repacking the bearings I sent an email to SKF(asktheengineer) asking how many CC of grease per bearing is ideal, I don't know what to make of the response shown below.

Bearings are typically filled according to the speed of the application at installation. Usually, fine to fill/pack 100% of the bearing itself when first installed. Some references call for 50% or even 30% pack in the bearing if it's a "fast" application (>50% of the Limiting Speed of the bearing).

The7207BEP bearing needs about 27.77 cm3 for 100% fill.



I think he slipped a digit and means 2.7cm3, I used a syringe and used about 1.5cc probably a little less.
 
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