Countersinking inside of tail block?

[mqmurphy]

Hello - I'm trying to install a K&K Pure Mini pickup in an old arch top guitar - first problem I've encountered is that the tail block is too thick for the endpin jack to make it all the way through. The solution suggested by the tech at K&K was to countersink the inside of the tail block. The only way I can imagine doing that is with a Dremel bit that has a long shaft - could be inserted from the outside of the end pin hole - only need about 1/8" relief in 1/2" hole for clearance for the nut and washer to make it into the tail block. Sources for long shaft bits? Suggestions? Thanks.

[Tom West]

The correct tool is a reverse counter bore. The shaft of the tool should be close to the same size as the hole. They look like a spade bit but have the cutting face on the back instead of the front. You would insert in into the tailblock hole from inside the guitar and the chuck it in a drill on the outside of the guitar and then pull towards yourself. Not sure if you can envision that. They can be made with a bit of rod and a tool bit or piece of file shaped to a cutting edge and captured in a hole cut across the rod and secured with a small set screw.
Tom

[stanron]

There's a long thread on this subject at frets.net.

http://www.fretsnet.ning.com/forum/t...age=1#comments

Several solutions suggested. It's worth a read if you have the time.

Scroll up to the top of the page to get the thread start.

[mqmurphy]

Originally Posted by Tom West

The correct tool is a reverse counter bore. The shaft of the tool should be close to the same size as the hole. They look like a spade bit but have the cutting face on the back instead of the front. You would insert in into the tailblock hole from inside the guitar and the chuck it in a drill on the outside of the guitar and then pull towards yourself. Not sure if you can envision that. They can be made with a bit of rod and a tool bit or piece of file shaped to a cutting edge and captured in a hole cut across the rod and secured with a small set screw.
Tom

Thanks, Tom - I can picture that. It's a possibility.

[mqmurphy]

Originally Posted by stanron

There's a long thread on this subject at frets.net.

http://www.fretsnet.ning.com/forum/t...age=1#comments

Several solutions suggested. It's worth a read if you have the time.

Scroll up to the top of the page to get the thread start.

Thank you, Stan - will check that forum out.

[mqmurphy]

Thank you for those replies - speedy and helpful. I'm thinking the most likely solution for me is the re-ground spade bit. Access to the tail block in the arch top is the problem - I'll make up some kind of plug/bearing to keep the shaft of the bit centered in the hole. Wish me luck!

[Alan Carruth]

A re-ground Forstner bit will do a cleaner job. Thread the shaft out through the end pin hole, chuck it in a hand drill, and remember the reverse the thing. It makes a nice flat clean bottomed hole.

[phavriluk]

At the risk of embarrassing myself by missing something really obvious,

I can see how a 1/4" jack with a threaded body would need a counterbored hole so's the nut can thread its way onto the shank and have something for the nut to push on to hold the jack in place, but there's any number of jacks that mount with external screws that would not need such a counterbore, the wire comes through the hole, gets soldered onto the jack, and the whole business gets attached with three screws from the outside. No fussing required.

If our OP is trying to use the jack that came with the pickup, and it's of the threaded-shank variety, I can see where the problem arises, but if an externally-attached jack is used, there is little problem. And all these 1/4" phono plugs are electrically interchangeable, once the wires are in the right place. A few minutes with a multimeter will sort out which wire goes where.