RE: [CR]Naked ritchey, falcon, pinerello

(Example: Production Builders:Peugeot)

Subject: RE: [CR]Naked ritchey, falcon, pinerello
Date: Sun, 5 Mar 2006 03:22:09 -0800
Content-class: urn:content-classes:message
Thread-Topic: [CR]Naked ritchey, falcon, pinerello
thread-index: AcZAEuhnltCNtcsdS9qhzjsh2D0yrAAMhXFg
From: "Mark Bulgier" <Mark@bulgier.net>
To: <tsaleh@rocketmail.com>, <Classicrendezvous@bikelist.org>


Tarik Saleh wrote:
> There were some Japanese frames (Bridgestone) that had copper
> furnaced brazed HT and head lug pre assemblies that then were
> brass brazed into frames,

Yes, and those Bridgestones were left so weak that the headtubes yielded in normal riding - they stretched out such that the headsets became loose where they seat in the head tube (not all of them, but enough). The great Jobst Brandt declared this impossible - no head tube could be that weak - but I saw at least three or four of those Bridgestones with headtubes stretched from "JRA" as we used to say in the bike biz (Just Riding Along). Jobst was right for most bike frames, which luckily are not copper brazed.

Copper melts at a MUCH higher temperature than brass, and damage is done to the steel at those temperatures - and not just from the temperature. There is also brittleness caused by inter-metallic compounds that are formed between copper and steel. I'm not a metallurgist, don't even play one on the Internet, so that last bit is hearsay. But this I know from ample first-hand experience: excess temperature and copper brazing are both bad for bicycle steel.

Mark Bulgier
Seattle WA USA