1906 american eagle cutaway

[sheepherder]

Originally Posted by DonVoigt

Well,
you broach it or clean it up with a file; or use a key cutter.

I was watching The Science Channel/How It's Made last week and they showed some kind of bandsaw but instead of a saw blade it had a diamond-impregnated wire. I forget what they were making/cutting, but it was an interesting tool.

I had some interior cuts made not long ago with a Wire-EDM and although it was very precise it was also slow and the surface finish was 'satiny'.

A broach would be the most likely tool here, I think. The round hole at one end of the slots is a gave-away.