re: [how far back for] [CR]Double butted spokes

(Example: Racing:Roger de Vlaeminck)

Date: Mon, 2 Oct 2006 11:57:28 -0400
From: <sachshm@cox.net>
To: tsan7759142@sbcglobal.net, classicrendezvous@bikelist.org
Subject: re: [how far back for] [CR]Double butted spokes
Sensitivity: Normal


Tom Sanders (TS) asked:

Tom: Yesterday afternoon while detailing out a set of wheels off a '62 bike that I am sure is all original I was surprised to note that it has double butted spokes. When did they appear on the scene?

Harvey: I'm not sure, but they certainly were a mature industrial product during the 1930s. I built up my '38 Paramount with factory-spec Torrington 15/17 db spokes, provided by Ted Ernst. BTW, please note the 15/17, one size lighter/smaller than the today's standard 14/16. The work well, but the plating does blemish.

Tom: <snip> I believe the Swiss ones even use the same amount of metal, but hammer the middle of them in a press or something very similar to compress the middle of the spoke, or so I have been told.

Harvey: I hadn't thought about this, but what you refer to would be forging. Alternative might be drawing the wire through a second (openable) die. Both would tend to align the grain structure longitudinally, I think, increasing tensile strength. This is good, but regular spokes are also drawn from thicker stock. In either case, reducing the diameter by drawing or forging will elongate the spoke (the mass has to go somewhere).

harvey sachs
mcLean va usa