Friday, October 11, 2013

Scorcher Project - Bottom Bracket/Crank

The frame and other parts now powder coated and I'm ready to start reassemble.  First will be working on the bottom bracket and crank.  I will be using the original 1970 Sports bottom bracket.  I cleaned the old grease from the cups and spindle, replaced the 22 (11 each side)  1/4" ball bearings, packed the cups with new grease, then installed and adjusted the spindle play.

The crank is also from the 1970 Sports.  I wanted to retain the Raleigh Huron chain wheel and cranks.  The surface rust was removed then polished and buffed.  Next was to install the crank cotters.  The Sports uses a 9.5 mm cotter.  These once were very common to find, but finding quality cotters is getting more difficult.  I was able to purchase some excellent quality cotters from my LBS, Velo-Classique; however the flat on the cotters would need to be filed to fit the Raleigh cranks.

Cotter before filing
I used a method discovered on the web to position/hold the cotter in the vice for filing.  It uses a magnet and spacers to hold the cotter, so the flat will be held parallel with the vice jaws when filing.

I didn't have a bar magnet so I used the magnet on my digital angle gauge.  The cotter flat is against the magnet.

I used two strips of plastic .030 thick as spacers.

The cotter is positioned in the vice across the spacers, then the vice is tighten to hold the cotter.  The flat of the cotter is held parallel above the vice jaws by the height of the spacers used. 

Ready for filing, remove the spacers and use vice jaws as a guide.  When the file starts to drag on the vice jaws you're done.


Cotter face after filing.

The cotters can now be installed in the crank arms, I use a modified Harbor Freight motorcycle
chain breaker to press cotters into the crank arms.

Here are the bottom bracket and crank installed.  I will be using MKS Sylvan "rat trap" pedals for this project.

This is the bike partially assembled with the hub resting in the dropouts.

Next will be preparing the hub and adjusting the chain line; then wheel building can commence.

Please share your questions, comments, and experiences.



  1. holy crap, the motorbike chain tool press is a brilliant idea! How did you go about modifying it? You should do a write-up of that.

    1. Go to for info on modifying.