Re: [CR]Stress risers and Pantographing


Example: History:Norris Lockley

From: "aldoross4" <aldoross4@siscom.net>
To: "Tom Sanders" <tsan7759142@sbcglobal.net>, <classicrendezvous@bikelist.org>
Subject: Re: [CR]Stress risers and Pantographing
Date: Wed, 11 Jan 2006 10:38:21 -0500


Absolutely! Any "break" or corner in the surface of a part - weather from damage, poor finish, or engraving - will produces a stress riser. This does not necessarily mean that this is the point at which a part will fail, or even that it will fail at all, but a possible fracture is most likely to form at a stress riser.

Also, post-anodizing engraving removes the protective layer and leaves the aluminum below exposed to environmental contamination, pitting, and possibly subsequent failure at that point.

If Campagnolo moved the logo on the C-Record cranks, then they must have found that the original engraving was at a critical spot.

Aldo Ross Middletown, Ohio

----- Original Message Follows -----
From: "Tom Sanders" <tsan7759142@sbcglobal.net>
To: <classicrendezvous@bikelist.org>
Subject: [CR]Stress risers and Pantographing
Date: Wed, 11 Jan 2006 09:40:45 -0500


> I have been told that on the prototype C Record cranks

> there was an engraved or Pantographed logo that left

> stress risers in the arm and crank failures resulted so

> the logo was subsequently moved and laser etching used

> instead. My question is...Does Pantographing of parts

> typically leave such risers and why or why not? I

> certainly have not heard of any great amount of failures

> among Pantographed parts. Tom Sanders

> Lansing, Mi