Re: [CR]headset keyed washers

(Example: Framebuilding:Tubing)

From: "Robert Clair" <r.clair@cox.net>
To: <classicrendezvous@bikelist.org>, "John Betmanis" <johnb@oxford.net>
References: <3.0.6.32.20070120214037.008a2290@mailhost.oxford.net>
Subject: Re: [CR]headset keyed washers
Date: Sat, 20 Jan 2007 21:01:59 -0600
reply-type=original

... is this because it is a top loaded force ? what about side loaded forces like pedals on cranks ? hub shells outside of axle bearings ? anyway appreciate this dicussion very much.
yours,
r clair
alexandria, va 22308


----- Original Message -----
From: John Betmanis
To: classicrendezvous@bikelist.org
Sent: Saturday, January 20, 2007 8:40 PM
Subject: RE: [CR]headset keyed washers



> At 08:28 PM 1/19/07 -0800, Scott L. Minneman wrote:
>
>>I spent a bunch of years in physics and engineering courses, but none if
>>that is helping me formulate a explanation for a properly fitted and
>>assembled headset coming loose in the way Dale describes.
>
> Well, when you jam 2 nuts together there is very little material to
> compress in the nuts, or material to stretch in the steerer. The most
> secure way to do it is to overtighten, which you don't really want to do,
> because it permanently deforms the threads. By having a washer in between,
> you are compressing the washer and stretching the steerer, thus are able
> to
> get more preload before causing permanent deformation. It's the same
> principle as stretching a bolt within its elastic limit when you torque
> it.
> Oh, sure, you can tighten a headset securely with no washer, but you run
> the risk of damaging the threads over time by doing this. There is a very
> fine line between too tight and too loose without a washer.
>
> John Betmanis
> Woodstock, Ontario
> Canada