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Full Version: O-rings for HP41 Card Reader repair
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thank you, MoHPC!! Being an enthousiastic HP Calculator user for over 20 years i am very happy to have found this website. With all the information i found here, i have been able to repair my card reader which has been ten years in a drawer! (-the cards would'nt get through anymore...).

I want to post this to the forum because apparently there is some confusion regarding the type of O-rings in the Article N°57 of Dave (an article in the Articles Forum). I found out that the type 006 O-rings are in fact the same as the englisch 1/4" OD - 1/8" ID. The 006 type has 2.9 mm ID and a rubber thickness of 1.78 mm, what makes an OD of 2.9+2*1.78=6.46 mm. Here you can find more info on O-rings: http://www.marcorubber.com/sizingchart.htm

In Tienen (Belgium) i could only find a metric O-ring size "01" of OD 6 mm and ID 3 mm which also works fine!

regards, Hugo

Where did you find your rings ?

Actually 006 o-rings tend to be a bit too big. Size 005 is better. Some 005's are 15/64" OD, others are 7/32". I think the 15/64 are probably ideal... but I much prefer the silicone rubber tubing.

Found them at a local car repair center, BVBA Brems, Ambachtenlaan 28, 3300 Tienen (see http://www.brems.org at a price of 0.20 €/piece (they only have a small stock!). These were the smallest rings available.
regards,Hugo

Bedankt !

(thanks!)