M1a strapjack too short for vintage Gibson tail block

[Dakota FlameRider]

I have a 1956 Gibson Southern Jumbo that I had a cheap soundhole pickup installed in a couple of years ago. I decided to upgrade to a M1a. I didn't expect any problems since I had a luthier install an end pin jack to make a semi-permanent installation for the old p/u and the hole was already there. First, I found that the old end pin jack was a tapered one that pressed into the original tapered end pin hole. I was prepared for that and was ready with a reamer to ream the tapered hole to the 1/2 inch one required for the M1a. I was not prepared, however, for the fact that the threaded shank of the M1a strapjack was about 1/4" too short to pass thru the tail block of the vintage Gibson.

Fortunately, after a period of sheer panic, I realized that if I took ALL the washers off the strapjack the entire assembly would pass thru the hole. I was able to slip an appropriately sized flatwasher down the body of the jack and epoxy it in place to form a retainer that allowed the jack to protrude the right amount for all the external hardware to fit properly.

I don't know how unusual this problem is but I wanted to pass it along in case anyone else runs into a similar situation. I was also wondering if there is such a thing as an "extra long" jack available for guitars with thicker tail blocks?

[Bryan McManus]

By far, the best way to get around a thicker tail block is to have the hole counter-sunk on the inside surface of the tail block.

You may have issues with the epoxied washer being the only stop point on the internal hardware.

Done correctly, countersinking will be invisible from the outside and will not affect the structural integrity of the guitar.

[Dakota FlameRider]

Thanks, Bryan. Countersinking was my first thought, but I don't have the equipment to do it myself and the nearest qualified luthier is 5 hours away. I will definitely take your advice the next time I make that 5 hour drive.

BTW, the M1A is FANTASTIC!!! It took an afternoon to tweak the pole pieces but BOY was it worth it. And please let the powers-that-be know how MUCH we appreciate the great access to accurate, prompt support this forum offers.

[Bryan McManus]

Hi Dakota,

Thanks for the appreciation. We're very pleased with this forum and the increased access it gives users to support as well as to communicate with each other.

[RadioC1ash]

I know this thread is super old, but in the off chance that this might help someone...
I ran into the same issue with the M1a and a thicker tail block. Really tough to get a drill inside the guitar to counter-sink the hole for the endpin jack. So, I made this little tool from a spade bit. Using a metal file I duplicated (approximately) the leading edge of the tool on the trailing edge. You can feed it through from inside the body of the guitar, and then attach it to the drill on the outside. Seemed to be just the ticket for me!
Spade.jpg

[Caleb_Elling]

Thanks for sharing! I'm sure this will help those who have this same issue.

[vaporlock]

I know this thread is super old, but in the off chance that this might help someone...
I ran into the same issue with the M1a and a thicker tail block. Really tough to get a drill inside the guitar to counter-sink the hole for the endpin jack. So, I made this little tool from a spade bit. Using a metal file I duplicated (approximately) the leading edge of the tool on the trailing edge. You can feed it through from inside the body of the guitar, and then attach it to the drill on the outside. Seemed to be just the ticket for me!

Thanks for the tip! Excellent idea, which I probably would have never thought of.