Help with "Step Timing Calculator"

If more than one or two, I'd say the probability is quite high.

If you need to replace balls, be careful they must be very precisely sized.

as todd says be careful on size , the track should be just about full , if you jam an extra one in , you'll find it will lock up and not move
the balls do track along the slide and move around , so an odd one missing wont harm directly , although i'd say more than 2 missing could cause intermittent problems

If you need more balls. I'd suggest contacting the screw manufacturer. You will need the serial number from the nut and or maybe the screw. Usually these numbers are hand engraved on the nut somewhere. They should be able to tell you the size and probably supply you with some replacements.

The link in the html manual does not work. Is this spreadsheet still available?

Try the link in this earlier post:
forum.linuxcnc.org/16-stepconf-wizard/26...ulator?start=0#34752

This is what comes up from that link