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HP Forum Archive 17

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Teflon or Urethane O-Rings for HP41 card Reader : Where can I find some?
Message #1 Posted by Antoine M. CouŽtte on 5 May 2007, 3:35 p.m.

Hello to all !

I need to replace the O-rings of my two HP41 card readers.

I am aware that this subject has been earlier adressed here.

Very recently Massimo Gnerucci from Milan Italy very kindly indicated to me the following links to cover this subject: ebay HP41 Card Reader Repair Service , ebay HP41 Drive repair Service , ebay O-Rings sold by Mark Hoskins , and Card Reader Repair Short fix Approach by Mark Hoskins .

Still, I think I also read somewhere else - but I am unable to recover this in the Archives here - that there also might exist some Teflon or Urethane O-rings.

Could anyone give me information about such ( possibly existing ) Teflon or Urethane O-rings : qualities ( namely efficiency and usable life ) and price compared to compared to conventional Rubber O-rings ?

Thank you very much in advance.

Antoine M. CouŽtte

      
Re: Teflon or Urethane O-Rings for HP41 card Reader : Where can I find some?
Message #2 Posted by Randy on 6 May 2007, 2:06 p.m.,
in response to message #1 by Antoine M. CouŽtte

Teflon would be the worst choice you could make... since it is friction you want, not slip. Urethane was the original drive surface but you'd be hard pressed to duplicate it and finding the right characteristics in an o-ring would be difficult at best.

IMO, silicone tubing works consistently better due to more surface area and will no doubt survive the test of time far better than o-rings. If it is cheap and easy you want, go with o-rings. If it is a reliable and long-lasting repair you want, take the time to source some 1/4 inch OD silicone tubing.

Edited: 6 May 2007, 2:10 p.m.

            
Re: Teflon or Urethane O-Rings for HP41 card Reader : Where can I find some?
Message #3 Posted by Antoine M. CouŽtte on 6 May 2007, 8:52 p.m.,
in response to message #2 by Randy

Quote:
If it is a reliable and long-lasting repair you want, take the time to source some 1/4 inch OD silicone tubing.

Thank you very much Randy for your reply.

Any idea about where to source OD silicone tubing in the USA ? I quite often come to Chicago O'Hare, where I am currently standing ( I will take off to-nite but will fly back within 10 days ).

Best Regards

Antoine

                  
Re: Teflon or Urethane O-Rings for HP41 card Reader : Where can I find some?
Message #4 Posted by Richard Ottosen on 6 May 2007, 9:24 p.m.,
in response to message #3 by Antoine M. CouŽtte

Antoine:

"OD" means outside diameter.

You can find silicon tubing at hobby shops. It is used as fuel line for model airplanes. I don't know for sure that 1/4 inch outside diameter is a size that is used for fuel line.

Silicon tubing is sometimes used for air supply lines in fish tanks. The tubing I found has a bluish tint. It has a more rubbery feeling than the clear tubing. Again, I don't know if it is going to be the size you need. The tubing I have is about 10% larger than 0.25 inches in diameter. Maybe Randy can tell us if that is close enough to work properly.

-- Richard

                  
Re: Teflon or Urethane O-Rings for HP41 card Reader : Where can I find some?
Message #5 Posted by Randy on 7 May 2007, 8:23 p.m.,
in response to message #3 by Antoine M. CouŽtte

Send me your postal address via the Museum's email system, I'll send you some cut-to-length pieces.

                        
Thank you again Randy ...
Message #6 Posted by Antoine M. CouŽtte on 8 May 2007, 10:44 a.m.,
in response to message #5 by Randy

... for your most kind reply.

Back to Europe since last night, I attempted to register with HP Museum in order to send you postal address via the Museum's email system, but could not succeed.

So, and if it is acceptable to you, would you be so kind as to contact me through the hereenclosed e-mail address ? I will then give you my home address.

If you prefer not using this solution - which I totally understand and respect - I will then try to devise another way for us to get in contact.

Thank you again and Best Regards

Antoine M. CouŽtte


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