Re: [CR]Stress cracks on Campy NR/SR crankset spider

(Example: Framebuilders:Jack Taylor)

Date: Wed, 14 Dec 2005 06:18:40 +0100 (CET)
From: "Sergio SERVADIO" <servadio@mail.df.unipi.it>
To: Dan DiMaria <ddimaria@snowmasslodging.com>
Subject: Re: [CR]Stress cracks on Campy NR/SR crankset spider
In-Reply-To: <NEBBIOLCILDJFFDENBFEGEMKLCAA.ddimaria@snowmasslodging.com>
cc: classicrendezvous@bikelist.org

On Tue, 13 Dec 2005, Dan DiMaria wrote:
> OK, I'm probably revisiting an issue that's been visited a thousand times,
> but I did search Google (got a few teases but nothing substantial) and the
> Classic Rendezvous Archives (found nothing). What's the consensus on the
> small stress cracks where the crank arm meets the spider? Is the crank
> trash? Does filing it after the fact do anything or is it too little too
> late? For that matter, is filing it and rounding off that corner before the
> crack develops recommended? Has anyone ever seen one break catastrophically
> at this point?

I have been turning those, and only those, cranks for well over thirty years. None has failed.

However, at a shop, I have seen one with a starting hairline crack and heard (from friendly Jobst) that this might in fact happen more often than I could ever imagine.

Certainly a rounded corner is of benefit to prevent or to cure after.

Sergio
Pisa