Cast Lead Thread ?

[No.3]

Yeah, I recall that the one I encountered was made to use the can material as the shim stock. You can buy steel and brass shim stock from engineering supplies outfits by the sheet or the pack, possibly not the cheapest. If you make the punch/die set to suit the stock you have available, that kind of gets around the sourcing issue for shim stock. I don't think there was any functional issue with the can material as far as I can recall, but the die and punch clearances needs to fit the shim stock.