Bill,
I've never seen file work like that.It has to be very demanding to hold the depth of parallel lines the same!
There used to be an old gunsmith in this area that was trained in Germany.He told me that,for the first 6 months of his apprenticeship,he did absolutely nothing but learn to file.He made a lot of his small parts with files.
Thanks for posting the picture!
Toby,
Is he going to use a semi-auto for the first one? I expect working on a flat surface is different than round surfaces like a revolver cylinder or barrel.
Hope you show some pictures when he's finished!
Ron