Zithers!! I recommend against using any power tools to set your zithers and remember to insert them such that you will go in further as you wrap and tighten the string.
Aslo, be very careful to not get oil or wax into a Zither hole. Those pins are threaded and rely on friction to hold their tension.
I did a lot of modification in this area, part by intent, I wanted blued pins), and part in recovery from a mistake that I made.
I would suggest you take a block of hardwood, cherry if you can find it, and practice with a Zither until you get used to them.