HP Forum Archive 19

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HP-67 clutch rebuild problem Message #1 Posted by Michael de Estrada on 8 Feb 2009, 3:11 p.m. The clutch metal sleeve has separated from the worm gear shaft and all the hard filler material (glue or epoxy?) has clumbled and separated from the worm gear shaft. How do I re-attached the sleeve to the worm gear shaft so that it is tight and concentric?

Re: HP-67 clutch rebuild problem Message #2 Posted by Rainer Wiedemann (Germany) on 8 Feb 2009, 3:38 p.m., in response to message #1 by Michael de Estrada Michael, maybe this article (http://www.hpmuseum.org/cgi-sys/cgiwrap/hpmuseum/articles.cgi?read=262) is helpful. There might be even more informations in the museum's article forum. You could also consider have somebody turn a sleeve, which fits directly on the motor shaft with one end, the other end matching the worm gear diameter and glue the parts together thereby giving up the clutch at all. This would yield perfect centering of all parts. Considering the size of the sleeve, this would have to be a skilled watchmaker.

Re: HP-67 clutch rebuild problem Message #3 Posted by Michael de Estrada on 8 Feb 2009, 7:54 p.m., in response to message #2 by Rainer Wiedemann (Germany) Rainer, Thanks for your assistance. I decided to make a coupling using wire insulation and eliminated the clutch operation. I used wire insulation with an ID = motor spindle OD and OD = clutch sleeve ID. I then bored out the insulation piece at the worm gear end until it was a very tight fit and used a modeling knife to remove sufficient outside material so I could force the sleeve over it and secure it to the worm gear shaft. I applied a tiny drop of superglue to the motor spindle and pushed it though the captive insulation piece and into the end of the worm gear shaft. Of course by doing this I have eliminated the clutch function, but I have tested the card reader by applying 1.5V directly to the motor and pulling a card through repeately, and there was no sign of the motor laboring or the card jamming. Everything is now very smooth and quiet now, so hopefully this will prove a safe fix.

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