Dan1954 wrote:

I just joined DIY and I have a question on tools. I am considering
making my own and possibly selling wood guitar tuner buttons. The
problem I have is on the shaft side of the button is a 3/32" x
5/32" rectangular shaft slot with rounded ends.
http://img.photobucket.com/albums/v3...ttons-hole.jpg.
I was looking at mortising bits but they are just too big. How would
anyone go about making this hole? Thanks in advance for you help.

Cutting that would be a bitch. I'd drill the hole oversize, fill it
with epoxy and use the correctly sized piece to cast the hole.

I'm not sure how much stress the tuning peg is under, but replicating
the plastic insert from that picture you linked to in epoxy would
definitely be stronger than a hole in wood and would last longer.

R