Olympus-OM
[Top] [All Lists]

RE: [OM] cross point screws follow up; JIS cross-point screws

Subject: RE: [OM] cross point screws follow up; JIS cross-point screws
From: Michael Collins <Michael.Collins@xxxxxxxxx>
Date: Tue, 03 Sep 2002 15:26:46 -0400

 Well, to add to the fun, the range of screws in the model shop that looked
like they might be the right size were called "0-80 x 1/4" and "0-72 x 1/4".
The ones for the Rolleiflex were a tiny bit smaller than the 0-72, but a lot
bigger than the 0-80.

 The metric 2x... ones were sensibly named, but the screws in question were
about 1.5mm or so across, so I don't think that 0-72 = 1/72nd of an inch,
either

There are literally dozens of screw thread standards and designations, though only a few relevant to photographic equipment. An ANSI list can be found at:

  http://www.simpsonenterprises.biz/tech_specs_ansi_thread.html

The examples you give are "Unified Inch Screw Threads" in ANSI terminology. Some history at:

  http://users.pipeline.com.au/aandb/expert/vee.html

The "0" is a code for the screw diameter (approximately 0.06"), with codes beginning at 0 [there are also 00 and 000 sizes, as the scale was extended in the other direction]. The "80" is threads per inch.

In household use, you're probably familiar with 6-32, 8-32, 10-24 and similar sizes; same terminology.

There's another standard, from ASME, for even smaller screws (Unified Miniature Screw Threads). Story at:

  http://www.normas.com/ASME/pages/B1.10M.html

Michael

P.S. Mostly distilled from Google searches, I don't really know all of this :-) .

< This message was delivered via the Olympus Mailing List >
< For questions, mailto:owner-olympus@xxxxxxxxxxxxxxx >
< Web Page: http://Zuiko.sls.bc.ca/swright/olympuslist.html >


<Prev in Thread] Current Thread [Next in Thread>
Sponsored by Tako
Impressum | Datenschutz