(New version 2021-06!) This tool is made from tempered high-carbon steel and both tips are finished by hand. The tips are carefully sharpened to the correct specification to allow it to emboss the slot effectively without shredding or otherwise damaging the slot. I ensure that each tip is perfect.
The Five Cent Tuning Tool™ is used to make small changes in pitch to reeds on the blow plate without needing to take the reed plates off the comb. Use it to touch up the tuning of reeds that are only slightly out of tune (by about five cents or less) without messing up the reed shape or gap.
A pilot hole for this tap can be drilled with a 3/64" drill bit - that's a commonly-available drill bit in the US and Canada. In most cases, the rivet hole is already the perfect size and no further drilling is needed.
To use this tap, I recommend you use a tap handle or pin vise. I can provide one if needed.