I put a
micrometer on the capstan in my 9145A. It had turned to goo,
but not melted yet---so it was intact, but difficult to measure
without deforming. I got a reasonably accurate measurement off it.
Based on experience, this should be close enough to affect a workable
repair (though I haven't gotten to actually doing the repair yet).
HP 9145A 36 Track < 0.800"
That should be read as "just under 0.8 inch."
0.8" = 20.32mm Maybe the exact size is 20mm. Although I would normally
expect imperial measurements in an American device, I have noticed that
all the screws in this drive have metric threads. So perhaps it is a
sensible diameter in milimetres.
Furter hto this. I've just put the micrometer on the (cleaned) hub of the
9144 that's on my bench. It measues 0.5925". This is almost exactly 15mm,
and I suspect that's what it should actually be. Which makes a metric
dimension for the outside diameter more likely.
So I guess the 'tyre' is 15mm I/D, 20mm O/D (which would give a wall
thichness of 2.5mm). Now to find some suitable tubing...
I am pretty sure that all these drives use the same size capstan, BTW.
-tony