Today the cleaners came and I was underfoot so I headed to the workbench to get something done on the project. Rather than just sand away, I wanted to do something a little more rewarding so I installed threaded inserts in the neck. I chose the E-Z Lok 329-008 8-32x5/16"steel inserts. I shimmed the jaws of the vice (thanks for the tip, BigSteve) to fit the taper of the neck, clamped it in and aligned the holes with a reversed drill bit then cut them shallow with a 1/4" Forstner bit (again, thanks BigSteve). All four started, I set the finished depth for the Forstner bit and went back and drilled to the proper depth to allow the inserts to set in slightly below the surface of the heel - 3/8". I took a countersink and ran it a couple of twirls by hand to take the hard edge off the holes, Then I tapped the holes with a block drilled to keep the tap aligned (thanks for that one, Kevin). When I was done, I screwed an insert in that had been drilled out to align a 3/32" drill to clean the hole about 1/4" deeper so the screws wouldn't bottom and apply unnecessary lifting pressure to the inserts. Instead of putting tape on the bit to the proper depth, I used a dowel that I'd drilled years ago for a depth gauge and set the proper depth so I wouldn't 'oops' into the fretboard. I then blew the dust out of the holes and installed the inserts with a screwdriver. I'm pleased with the result.
The screws I got are 1 3/4" long and will need to be shortened by 3/8" or so before installing