Re: [CR] engraved vs. etched campy crankarms

(Example: Humor)

Date: Thu, 17 Mar 2005 16:53:09 -0500
From: "Julian Shapiro" <julians@optonline.net>
Subject: Re: [CR] engraved vs. etched campy crankarms
To: gpvb1@comcast.net
References: <031720052146.23454.4239FAAB000D071900005B9E2200748184CE0D909F09@comcast.net>
reply-type=original
cc: Classicrendezvous@bikelist.org

Slightly OT timewise but I recall a photo of Laurent Fignon sitting by the side of the road with a broken left crank arm in his hand.


----- Original Message -----
From: gpvb1@comcast.net
To: classicrendezvous@bikelist.org
Sent: Thursday, March 17, 2005 4:46 PM
Subject: Re: [CR] engraved vs. etched campy crankarms



> The funny thing is, I've never seen a first-hand report of a Campy R/SR
> arm (of any flavor or vintage) breaking right at the arm-to-spider
> junction. The vast majority of the ones that fail seem to do so at or very
> near the pedal eye (which certainly makes sense from a
> stress-concentration viewpoint).
> My informal CR survey last year turned up precisely zero vintage aluminum
> cranks (of any brand) that broke at the arm-to-spider junction. It
> actually surprised me a bit - I thought there would at least be *some*
> that broke there. Lots of cracks there, but no failures....
> I think the bottom line is: examine your vintage cranks (of any brand)
> around the pedal eyes very closely and frequently for cracks that radiate
> outward from the pedal thread, or for any cracks in that general area.
> These can be fatal. There is virtually always a crack before there is a
> failure.
> The R/SR arms were forged, then machined, BTW, not cast, AFAIK.
> Greg Parker
> Dexter, Michigan, USA
>
> Date: Thu, 17 Mar 2005 08:13:25 -0500
> From: "Daniel Artley" <dartley@co.ba.md.us>
> To: <classicrendezvous@bikelist.org>
> Subject: Re: [CR]engraved vs. etched campy crankarms
>
> I once spoke to a Campagnolo USA rep about the non fluted cranks after
> getting one in the mail to drill and tap for a 74 mm bolt circle triple.
> Of course I wanted the classic fluted one. The rep told me that the
> newer lazer etched cranks when molded, had an electrical charge passed
> through the casting that alligned the molecules along the lines of the
> spider and as a result was actually stronger than the older milled
> cranks. If you check closely, the sharp edged stress riser at the base
> of the arm and spider is not a sharp edge on the lazer etched model
> either. I can't say that this information also relates the the engraved
> cranks.
>
> That crank looks good on my not quite on topic road/path fixed gear, a
> keeper of the flame only in geometry.
>
> Dan Artley
> Parkton, Maryland
>
>>>> Jay Sexton jvs@sonic.net> 03/16/2005 8:19:06 PM >>
>
>
> Is there any truth to the story I have heard that the etched and/or the
> engraved versions of Campy crank arms broke due stress fractures from
> these processes?
>
> What are the locations of the logos on engraved and etched crank arms?
>
> Jay Sexton
> Sebastopol, CA