Every mechanical calibration should include a visual inspection of all
working parts. Some of the most overlooked parts of the apparatus are the
belts. If the belts are not being inspected for part of the mechanical
calibration, then the apparatus was not properly calibrated.
Some of the things to look for are proper tension, residue or dirt on the
chain or belts, worn parts, faulty operation of gear plates, and surging of
individual spindles. The belts should be lightly lubricated every 6 monhs
with a high vacuum grease. I use Thomas lubriseal, but others work just as
well. The guide post are the parts that the belts wrap around. These should
be cleaned with alcohol at this time. The grease mixed with dirt can
accumulate on these.
Be careful not to over lubricate them too. There can be too much of a good
thing.