29 Nov
2012
29 Nov
'12
8:26 a.m.
On 11/29/2012 09:33 AM, Chris Elmquist wrote:
On Wednesday (11/28/2012 at 07:38PM +0000), Tony Duell
wrote:
Yes. I've learned this now. I mistakenly assumed my
original ones had
decayed due to how the unit was stored (basically outside)-- and it was
extreme heat, cold and ozone that did it in. Now, it's pretty clear
it's an issue of the material and time.
OK. Thanks for
that. I've got the Tygon tubing in hand and will try
that first. Having a little trouble coming up with a good way to cut
it squarely though as it likes to deform while cutting. This is causing
the first attempts to come out non-uniform in height. I think I need
to put a 7/16" dowel inside it and then cut it on the dowel (or through
the dowel in a small mitre box)-- unless others have a good technique
for getting a nice square cut?
Chris
I just put an over size slice on the hub after cleaning and used
a bit of superglue to lock it. With the motor powered and tuning
I use an exacto knife to slice to top level with the top of the hub
and then make a cut down to metal about .160 down from there
for a clean edge. Any excess is peeled off. Then I used an emery
board while spinning to smooth and take the glazed surface off.
The whole process takes me a few minutes and I'm done.
I don't try to over complicate it. It needs to be the right width
for proper contact and no interference with the case and you
can eyeball that. That and reasonably round is good too.
One thing, even with tygon do not leave the tape in contact
when not in use, as everything I've tried (other materials)
get a flat spot in the roller that makes the drive noisy even
though it works fine.
Allison
Correct.
These rollers were not gooey in any way on inspection.
They were NOS replacements I ordered from a DEC parts supplier.
Unfortuantely,
they deacy with time, not really with use. So a NOS one is
likely to be unusable. I have
correct diameter (5/8"OD, 7/16"ID) tygon tubing as well as
various types of o-rings on order that I will try as replacements.
I am guessing about the durometer of the rubber so have a selection of
different hardnesses to try and see what works.
Rik Bos reported that a Citroen
seelve seal (the largest size) could be
stretched ovr the hub of the capstan in an HP tape drive that uses
simialr-sized cartridges. That mey be suitabkle for the TU58 too.