Hello MMD.  The rebuild of my Half Duo-Art has progressed as far as
the tracker bar, which I have removed and polished until it shines with
a brilliance dangerous to the eyes.  Of course it won't stay that way
for very long, and I am wondering about spraying it with 3M's #3900
Clear Protective Coating.  If anyone thinks this is a dumb idea, I'd
be glad to hear from them.

I should mention that I know it is inadvisable to use conventional
brass polish on small, thin metal parts, like small clock gears,
because of the abrasive nature of the polish.  But the tracker bar is
a fairly solid lump of brass and I don't think a polish or two is going
to affect it noticeably.

I have also done some cautious polishing of the hundred-and-one
(I think) nipples at the back of the bar, just enough to remove any
remaining residue of old rubber and to make the nipples smooth.  The
caution was engendered by a mental image of what might happen following
an inadvertent tug on the polishing cloth.

John Phillips in Hobart, Tasmania

 [ Many years ago I worked on a low-speed data logging magnetic tape
 [ recorder in which the many stationary tape guides of stainless steel
 [ were coated with glass micro beads to reduce sliding friction.
 [ The surfaces looked nice, too!  -- Robbie