Official Luthiers Forum!

Anyone else get really tense when drilling out that huge 1/2” hole in a beautiful finished (acoustic)guitar?


Sent from my iPhone using Tapatalk

Nope...

My 3rd one.


Sent from my iPhone using Tapatalk

For the jack you mean? Get a step drill bit and the proper reamer and you will never worry again.

Done it many times and have the correct tool(s). Most endpin units are actually designed for a 15/32” hole, so that 1/2” is looser than ideal. Stewmac carries the ideal reamer for the job. Expensive. I waited until it was 15% off. Still expensive.

The other issue with installing endpin jacks is that the tail block may be too thick and require a counterbore. Various ways to handle this. You’ll find posts on the forum about modifying a spade bit as a counterbore, but the slickest solution is a rear spot facer. I drill out the original endpin hole to 5/16” to accommodate the pilot shaft (indexed for correct depth) for the 7/8” spot racer and prepare the face. Then the Stewmac reamer to make the 15/32” hole. In a busy shop, these pay for themselves in no time.


Sent from my iPad using Tapatalk

As Tim said, get the reamer and you'll never worry. Expensive, yes, it takes a couple of installations to amortize it but not splitting a D-35 makes it worth while. And like Tim also mentioned, I had one guitar with a very thick end block and made a pull counter sink bit out of a spade bit. Mine is home made, kind of mickey mouse but worked fine.

+1 for step drill. You need the one that is long and has about 1/2" facets. Stop at 7/16" and do.the rest with the StewMac reamer.

_________________
Stay with the happy people.
--Reynolds Large

Actually, if you’re using the Stewmac reamer, there’s no need for a step drill bit. The reamer is very sharp and does a quick enlarging an existing endpin hole, or you drill a 5/16” pilot for guitars without an endpin.


Sent from my iPad using Tapatalk

15/32" is 11.901 mm.
Metric step drill to 12 mm cost = $15 or less
Stewmac reamer cost = $87
Never seen the need for the reamer myself, considering I had the step drill anyway....

_________________
The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

Sure, your way will work. A step drill from Harbor Freight costs less than $10 and does the lion's share of cutting. Plus, you can start with a 3/16" pilot hole drilled with a twist drill (to minimize tearout on inside block). I figure my StewMac reamer will last much longer by shifting most of the drilling to a disposable cutting tool. Also, many are using Baltic Birch as a tail block and the glue used is not especially kind to cutting tools.

_________________
Stay with the happy people.
--Reynolds Large

I drill on the drillpress with the LeeValley brad point bits before the back and top are installed. Works well for me.

I still use a step bit with the reamer. I drill the end pin screw hole out with a 1/4in bit then step up to 7/16th and finish with the reamer.

I’m gonna pre drill my next tail block. Pre fit the jack.


Sent from my iPhone using Tapatalk