Re: [CR]Cotters

(Example: Component Manufacturers:Ideale)

Date: Mon, 03 Mar 2008 09:43:22 -0500
To: <>
From: "John Betmanis" <>
Subject: Re: [CR]Cotters
In-Reply-To: <000f01c87d34$dd6c8ff0$6d7ba8c0@dkbwin2k>

At 08:45 AM 03/03/2008 -0500, David Bean wrote:
>The recent discussion of crank cotters reminded me of a long-simmering Q.
>What is the point of filing cotters?
>If you're using a new matching pair, the chamfer angles are the same, so the
>cranks will wind up opposite one another.
>Is it that the chamfered surface needs to be rougher (smoother?) to have the
>needed friction against the slot in the spindle?
>Is it that the cotter may not go far enough through the crankarm without
>making the chamfer deeper?

That last one would seem to me to be the main reason. So long as you start out with a pair of the correct cotter pins, which fit okay, the cranks should be at 180° to each other. Another reason would be if you're replacing just one damaged cotter with one from a different batch or trying to salvage an indented one that had been loose.

John Betmanis
Woodstock, Ontario