Re: [Classicrendezvous] Cold setting 753....

(Example: Framebuilding)

In-Reply-To: <CATFOODnrrXj7gC2DWp00000950@catfood.nt.phred.org>
Date: Mon, 20 Nov 2000 10:07:59 -0700
To: classicrendezvous@bikelist.org, oroboyz@aol.com
From: "Monkeyman" <monkey37@bluemarble.net>
Subject: Re: [Classicrendezvous] Cold setting 753....


>Gee Brandon, I am nervous about your statement. Or at least what some readers
>might infer from them..
>
>Of course one can (and obviously you have) cold set 753. Adding 2 mm per side
>is maybe not so risky, that doesn't mean it is a good idea. In fact 753
>probably should NOT be cold manipulated like we can "get away with" in other
>steels.
>
>I believe the approach to 753 should be certainly different from most other
>garden variety bike tubing and dramatic cold setting may likely lead to
>failure sooner or later. Even cold setting the stays a smidgen , while
>apparently successful, may have introduced stress risers that might be back
>to haunt you.

You are right that only people very experienced in cold setting techniques should try this. I'm not sure why you find 753 so much different or more brittle than other "super steels." In the past I've heard that the Manganese mix that Reynolds uses is softer than the Molybdenum used by other tubing makers. I'm not a metallurgist but this is what has been explained to me by many more experienced framebuilders. I've never hear anything about 753 being specificly different, beyond heat-treating, as far as cold setting is concerened from other tubesets of the late 80's and early 90's. 753 was much different than 99% of the tubesets in the late 70's though and I'm not talking about those early scary tubesets. I know at least two of the realigned rearends and the fork are being still being ridden very hard as messenger/racing bikes. Dale, I'm sure you've coldset more frames than I and maybe you've not done 753 but I think you'd be suprised how easy it is. I'm going to ask about 753 on the framebuilders list and see what those folks have to say and I'll post the results.

enjoy, Brandon"monkeyman"Ives

Brandon and Mitzi's-- "Wurld uv Wunder" http://darkwing.uoregon.edu/~capybara/

Monkeyman's on going bicycle part garage sale http://www.uweb.ucsb.edu/~mkirklan/salepage/garage.html

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