Making shims to adjust semitone forks

I use brass shim in four thicknesses:

The shim can easily be cut with sharp scissors (no not your wife's embroidery scissors!). The difficult part is getting a nice clean hole in the centre of the shim - here's the trick.

You need to make little punches to cut the shim. The way I did it is very cheap and works a treat:

Note: - if you are making new semitone forks, file them down to get the correct orientation rather than using lots of shims.

Various sizes of shim punch