HP2648A tape drive capstans
technobug at comcast.net
Thu Feb 16 02:22:19 CST 2006
I've been following this thread with interest since I'm in the midst
of restoring an HP Dynamic Systems Analyzer with two of the same tape
drives installed. Both capstans were gooey. I considered the various
suggestions and came up with an easy, inexpensive and accurate way of
restoring the rubber coating on the capstan. Plasti Dip International
<http://plastidip.com/consumer/index.html> makes a coating for tools,
insulating, weatherproofing, etc. You dip the object you want to coat
as many times as necessary to build up the necessary layer. The
product has just about the right consistency to replace the old
capstan rubber and appears to have excellent wear characteristics.
I was able to add 0.021" [53.3] coating to the capstan in three dips
to bring the diameter to the proper value. The diameter varies less
than 0.001" [0.025] over several measures and the run-out is around
0.002" [0.051]. This was on the first try. The drive appeared to run
the tapes on hand properly.
A couple of hints:
- stir the stuff well. However, not so fast as to introduce bubbles.
- attach an extension to the can of dip and add one or two drops of
solvent to the top of the dip. This will ensure that the area above
the surface of the dip is saturated with solvent and will prevent
- coat past the capstan onto the shaft. The added weight is
negligible and will ensure that the coating is uniform over the
My next try will be on a capstan for a DEC 7-track tape drive
belonging to a friend.
More information about the cctech