A few important points not to be overlooked......
1. These WAD type [circular hollow punches] are best used hammering against the
end grain of a supported piece of timber
2. Close grained hard wood or semi hard wood is preferable
3. Soft woods will result in the material being punched, tearing & elongating down into the softwood
If you needed 1 x steam gasket, make 6 x at the same time...cut one from plastic sheet...then use that as a jig plate for the punching of the bolt holes in the blanks & yes on the correct PCD & equally spaced...............
Saves a lot of time in the long run