[CR]The "charm" of Italian threads...the BiValent saga continues

(Example: Production Builders)

Date: Thu, 20 May 2004 20:50:01 -0400
From: "HM & SS Sachs" <sachs@erols.com>
To: classicrendezvous@bikelist.org, tr4play@cox.net, freitas1@pacbell.net
Subject: [CR]The "charm" of Italian threads...the BiValent saga continues

I've always been charmed by Italian bicycle parts, with their mixed metric/English units. Like a 36x24 BB cup, which is 36 mm diameter X 24 threads per inch (TPI). Always assumed that the Italian machine tool industry had been built on English or US lathes and other threading tools.

Well, with the help of Eric Elman (who provided a clean sample of the right model), I asked a machinist friend to make a few new Cinelli BiValent skewers. He worried that his Clausen lathe wouldn't be able to cut the threads, but not to worry:

the lever you turn mounts with a 6 mm X 26tpi thread, and its domed locknut uses a hardly-standard 5mm X 32 tpi Left-hand thread. So, Eric and Bob, I hope to have the double-thread skewers next week. Ah, since no one has recently seen a BiValent without major damage to the main screw, he's making them in annealed 4140, which should be much stronger than whatever the Master used. If you need one, too, drop me a note.

harvey sachs
mcLean va