Some time ago I was given an old Lockwood oval lock to suit a commerical mortice lock assembly. It had a C4 keyway in it but did not come with the key (the reason it was given to me), I wished to repin this lock to accept an old house key I had with 5 bittings, as luck would have it (or not) I had some keypins which fit this lock and bitting combination... apart from one pin.
After a bit of thought on the matter I took a longer keypin, placed it in my mini vice squared it off in relation to the jaws of the vice and took to it with a fine single cut file bit by bit untill it fit flush when placed in the plug with key, then I run a chamfer around the top edge with my file to mimic what I have on the other 4.
The final finish while homecooked in 5 mins has been flawless operation and has a better top face to it than some other key pins I have scrounged. I cannot feel any difference in lock operation to one with (initially) correctly sized pins or while practicing my SPP on this lock.
In short this may be useful to anyone who wishes to repin a lock, does not have a repinning kit but does have some pins from broken or disassembled locks.