Paul:
The cotter pin flats are filed so they will have full bearing (and therefore greatest strength and stability) with the bottom bracket spindle flats. They can be additionally filed to adjust orientation to obtain 180 degrees from the opposing crankarm. Use carpenter's chalk to check the area of contact with the spindle flat: Dust it onto the cotter flat, insert with a light tap from a mallet, remove and examine pattern. You may need to use a light film of grease to hold the chalk on the cotter pin flat. Chalk remaining indicates a low spot and bright sections the high spots that will need to be filed down to ensure full bearing. Bonus tip for the parsimonious - flour or talc pinched from your spouse will also work as a tell-tale.
For setting the pins once filing is complete, you can improvise a cotter pin press using a robust c-clamp with a section of pipe (or a socket) that will allow the threaded section to protrude as it is driven. You may need to use something to keep the upper portion of the c-clamps pad from walking around (and off) the pin as you tighten it.
regards,
Charlie Young Honey Brook, Pennsylvania USA
On Thu, 31 Jul 2008 08:34:41 -0400, wrote:
> Thank you to the few who replied to my query last night about fitting
> cotter pins - I should have realised that this was a well trodden query
> and answers were to be found in the archives. I am still a little
> unclear, however, how to properly file the cotter pins. What am I
> looking for in doing this in order to not only ensure that the pin will
> fit but also to put the cranks in proper alignment?
>
> Also does anyone have any tricks to setting the pins without using a
> press or a hammer?? I am not sure I want to invest in a press at this
> time (not sure how many cottered chainsets I am going to be installing)
> although Mark Stonich has one which is reasonably priced:
>
> http://www.bikesmithdesign.com/
>
>
>
> Paul B. Williams, BAH, MPhil, PhD
> Ottawa, Ontario, Canada
> castell5@sympatico.ca