These are the waste discs from punching 3/8 holes in 
copper. I made the punch out of a pushrod from Blue, 
my faithful '62 Ford Econoline. I sharpened the edges 
with a 3/4 generic brand silicon carbide grinding sphere 
and a drill. Press and grind. I use oak end grain as my 
punching surface; these discs have ragged edges because 
A) the punch has dulled and B) the oak I used for this 
pic was beyond its prime. The shape is what Boris desires, 
I think, but the size is wrong. But, thats the process 
I use. I hope this helps.