I have set of those cutters. I had given my old pillar drill away..... never used it, so there was a compromise when using plug cutters.
The 'Montana' brand were comparatively inexpensive, but had a retractable spring-loaded centre-point that allowed it to be used in a hand drill. They seemed to copy a pattern by 'Hitachi' that I noted was only sold singly in America some while ago, but not available in the UK. Compared to the 'Montana' cutters, the 'Hitachi' were comparatively expensive.
Anyway, the 'Montana' came in a set set from Rutlands and was quite affordable for small quantities of plugs - quicker than whittling them by hand.
The single draw-back I found with my set, - like Ollie mentioned above, was that, even at moderate drill speeds, they tend to get hot and scorch the wood a bit.
I noted that the tips of the cutting points that rotate into the wood were straight from the machine - not sharpened at all.
The solution was simple and very effective. A set of Diamond paddle-hones (which I use for all smaller blades with tight corners) can get onto the cutting faces and just a few strokes improved the corners immensely and solved that little problem.
So, if you can locate them..... they work well with a few minutes fettling.
Good Luck
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