Re: [CR]cottered cranks question


In-Reply-To: <5.0.2.1.1.20010209092928.009fa2a0@pop.erols.com>
References: <5.0.2.1.1.20010209092928.009fa2a0@pop.erols.com>
Date: Sat, 10 Feb 2001 15:44:11 -0500
To: Classicrendezvous@bikelist.org
From: Sheldon Brown <CaptBike@sheldonbrown.com>
Subject: Re: [CR]cottered cranks question


Harvey Sachs wrote:
>Let's think about cotter pins, hammers, and tools for a minute or
>two. I have not doubt that Mr. Reid can get a good fit with a file
>(I do ok starting with a grinding wheel) for his cotters.

Any monkey can operate a milling machine, but it takes a skilled mechanic to use a file and a hammer properly. The simplest tools are the ones that also require the most skill.
>I lack confidence that this will hold, and still require a robust
>method to remove the cotter.
>I recently acquired a VAR adjustable cam-over tool for this job,
>which is sort of equivalent to triple-sized vise-grips.

I broke one of those once, trying to remove a recalcitrant cotter. One of the support jaws snapped off.

The C-clamp-like Park tool is very much superior in my experience.
>Before that, I used a jig which was very helpful.
>
>To me, the key is to avoid hammering on a cotter when the crank is
>not supported. If you do that, the impact blows are transferred
>through the spindle to the ball bearings to the cups, increasing the
>likelihood of pitting problems (I believe, w/o metallurical
>knowledge).

All of the old books talk about this, but I believe it has no basis in fact. Nevertheless, supporting the crank is a Good Thing.
>So, I built a stand that sits on the floor. The "business end" is a
>vertical 2 x 2 board, with a shallow hole in the top to clear the
>end of the cotter or its nut. The top of the 2 x 2 is rounded a
>bit, and clamped with a radiator clamp to prevent splitting.

I have a similar tool, consisting of a short length of cast-iron pipe. Easier to make than your wooden rig, and more rigid. I don't use it anymore, though, since I got the Park press.

I have a couple of old articles on my Web site on this topic. See: http://sheldonbrown.com/cotters.html and: http://sheldonbrown.com/tooltips/cotters.html

Sheldon "Claw Hammers Are Better Than Ball-Peens" Brown Newtonville, Massachusetts +-------------------------------------------------+ | Some of my mother's paintings may be seen at: | | http://sheldonbrown.com/joyce | +-------------------------------------------------+

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