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John, That was a very useful FB post on installing endpin jacks. Looks like it works great. Years ago though, I bought SM's expensive jack hole reamer for elctric drills, and I've never looked back. It is a great tool if you end up doing enough jacks to warrant it.It will do 15/32" holes for a snug fit, or 1/2" holes for a looser fit. The reamer section takes you to a straight 15/32" diameter step section, and there is a further straight step section that is 1/2" diameter. Since the initial hole that has to be drilled to start the reamer is only 5/16", there is never any interior blowout like larger bits can cause. Very costly tool, and not for the casual user, but right for the job. The other tool shown is my prehistoric endpin reamer from the old days. I glued a handle on a 15/32" bit, drilled the hole just slightly undersize, used my cello reamer to enlarge the entry and then reamed it by hand with the drilled bit. Wish I had thought to use the step drill to enlarge the entry hole like you did.Happy New Year! Bob

as a machinist there is a tool out there called a hand reamer
https://www.amazon.com/findmall-Reamer- ... 102&sr=8-2
you drill the hole and this tool will finese it for a perfect fit

Thanks Bob

John- Those reamers are pretty cool. Whenever I see really interesting tools like that, I always wish I had a reason to use them so that I could buy one! There must be thousands of tools used in other disaplines that would be useful for building. Good thing no one is pointing them out! Anne and I almost always find 1 or 2 pennies on our gravel road when we walk the dog in the morning, but that does not buy many new tools! It remains a mystery to me why people lose pennies, but almost never quarters!-Bob

as a machinist we used so many tools that I can use cross over to the luthier trade. Step drills for tuners
hand reamers tapered end mills and tool tapers hand reamers grobet files pillar files die grinder just to name a few