I wanted a plug cutter to cut wooden plugs for fret markers for a guitar I am working on. I with an old bolt.
chopped up a 1/2″ stainless bolt
turned the threads down to 3/8″ shank so it would fit in a collet
made the other side shiny, bored the plug hole and tapered the cutting end
clamped it sideways in the mill to cut the side chip clearance
To form the ‘flute’ of the cutter where the chips clear out, I made an angled clamp block. I just eyeballed the angle I wanted and drilled a hole in a block of aluminum. Then I band sawed through the hole so it would allow clamping. The position of the end mill was also eyeballed. Position seems pretty forgiving.
fixture for holding the plug cutter at the right angle for cutting the ‘flute’
on-end view of the flute being cut
Below is the confirmation that it works! I drilled a whole bunch of plugs close together. Then I used a piece of tape to hold them all together while I band sawed them off.
future fret markers!
Amy Qian 
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