To answer File Handles question on the best method to drill very small holes through small pins or bolts I have found it is best to make a simple drilling jig from a small piece of MS. Even brass will do if the number of holes is to be small.
I use the cheap drills 61-80 and have found those supplied by Proops to be among the better.
Split Pins are easily made from wire scraped to half round section before cutting to length and bending into a pin – one leg slightly longer than the other of course
Here are some pics of those done for the governor pins on the Waller Engine
The drill jig and pin. Pin hole is about 20 thou
The wire is clamped tight to a piece of steel
and scraped to a half section using a piece of HSS tool blank
The pin is approx 2mm diameter, the split pin is 1/64 silver steel (yes that is right)
16 BA is the smallest I have threaded (the nut is 10 BA)
The parts all together. All six pins on the linkage have turned washers and fitted with split pins
All realtively easy to achieve so hope that's of interest to the OP and others
Best – Tug
Oh yes, a split pin is a split pin, a cotter, as said, is a totally different beast but that's our American cousins for you
Edited By Ramon Wilson on 14/08/2023 22:21:48