Acoustic End Pin Jack doesn't protrude quite enough - will my idea for a fix work?

[telel6s]

Earlier this year I installed a sound hole pickup in a 30ish year old Simon & Patrick acoustic I picked up used. The pickup, a MojoTone, sounds great.

However, the endpin jack doesn't protrude quite enough from the end of the guitar. Once the strap button is screwed on the jack, cables will often work their way loose just enough so the connection is lost, and I can't use a right-angle plug at all (which is my preference). The install manual says the jack should extend a minimum of 5/16" from the body of the guitar. I haven't taken a ruler to it, but I'm probably at 8/32" - 9/32". Enough so that if I sit/stand really still it works but even just regular playing can cause it to lose the connection. (I've attached two pages from the install manual below.) On the inside part of the jack, the hex nut and washers are as far down the jack as possible.

Here's my idea for the fix. Would love to hear from some of you if this makes sense or if there is a better idea.

From the inside of the guitar, drill a slightly larger hole at the endblock so that the hex nut on the jack can set inside of it. It would need less than a millimeter based on the manual's specs for min/max extension on the outside of the guitar., but because of the adjustable hex nut on the inside part of the jack this doesn't need to be real precise. Just saying I wouldn't be taking a whole lot of wood out of there. I should be able to do this with the hand reamer I used to widen the end pin hole in the first place. Does this make sense?

Thanks in advance.

 

[Jakedog]

Your solution is about the only one.

I used a dremel to do it once. I have no way to drill from the inside, so I used the dremel, a little router bit, and a very steady hand to leave the outside of the endpin hole the correct size, and make the inside of it slightly conical, so it was wider on the inside than the outside. It worked great.

 

[Freeman Keller]

I have installed a lot of end pin jacks as in your picture and there have been a couple of instances where the end block is too thick. What I did was make a pull cutter out of a 1 inch spade bit by squaring and sharpening the shoulder.



Insert the shank of the bit thru the end block via the sound hole, chuck the shank in your drill motor and pull as you run the motor. You will cut a nice flat bottomed one inch hole from the inside, then install the jack in the usual fashion.

 

[Freeman Keller]

For what it is worth, there are three other tools that make installing end pin jacks much easier. The long tapered reamer eliminates the possibility of splitting the end block. the long brass rod with a plug on the end lets you pull the jack into position, and the little caming tool that Frank Ford calls "jack the gripper" lets you hold the jack while tightening the lock nuts

 

[telel6s]

Your solution is about the only one.

I used a dremel to do it once. I have no way to drill from the inside, so I used the dremel, a little router bit, and a very steady hand to leave the outside of the endpin hole the correct size, and make the inside of it slightly conical, so it was wider on the inside than the outside. It worked great.

I didn't think about the dremel....I think I'd rather do this by hand but that's a good back up idea.

Thanks!

 

[telel6s]

I have installed a lot of end pin jacks as in your picture and there have been a couple of instances where the end block is too thick. What I did was make a pull cutter out of a 1 inch spade bit by squaring and sharpening the shoulder.

View attachment 1382045

Insert the shank of the bit thru the end block via the sound hole, chuck the shank in your drill motor and pull as you run the motor. You will cut a nice flat bottomed one inch hole from the inside, then install the jack in the usual fashion.

Cool idea. Unfortunately, I don't have any way to modify a spade bit like that.

Thanks!

 

[telel6s]

For what it is worth, there are three other tools that make installing end pin jacks much easier. The long tapered reamer eliminates the possibility of splitting the end block. the long brass rod with a plug on the end lets you pull the jack into position, and the little caming tool that Frank Ford calls "jack the gripper" lets you hold the jack while tightening the lock nuts

View attachment 1382087

Those all make sense for a repair bench. I did purchase a tapered reamer to widen the hole. But had no problem inserting the jack with my hand through the sound hole.

And if you look at the second instruction page I included, this jack has a small hole through the end of the threads through which you insert a rod (like an allen wrench) to hold the jack in place while tightening the nut. The fact that there is a jack-the-gripper tool makes that little hole seem all the more handy and ingenious.

Thanks!

 

[Freeman Keller]

Cool idea. Unfortunately, I don't have any way to modify a spade bit like that.

Thanks!

You could easily do it with a bastard file.

Those all make sense for a repair bench. I did purchase a tapered reamer to widen the hole. But had no problem inserting the jack with my hand through the sound hole.

And if you look at the second instruction page I included, this jack has a small hole through the end of the threads through which you insert a rod (like an allen wrench) to hold the jack in place while tightening the nut. The fact that there is a jack-the-gripper tool makes that little hole seem all the more handy and ingenious.

Thanks!

Yes the allen key in the cross holes will work if you don't have a better way to grip the jack. The clever little gripping tool works wonders with a recessed jack like a strat. And I have installed jacks in guitars that you can't get your hands inside, small bodies or guitars with f-holes. Just tossing out some options.

 

[Peegoo]

The modified spade bit in 'pull' configuration is the way I've recessed tail blocks for end-pin jack installs. I saw this in action at the Taylor factory in the 90s.

It doesn't need to be a precision cut because it's inside the guitar. However, it makes a very nice counterbore if the blade is properly ground.

 

[telel6s]

You could easily do it with a bastard file.

Yes the allen key in the cross holes will work if you don't have a better way to grip the jack. The clever little gripping tool works wonders with a recessed jack like a strat. And I have installed jacks in guitars that you can't get your hands inside, small bodies or guitars with f-holes. Just tossing out some options.

Hey! Only my dad is allowed to call me a bastard!


You assume I already have a bastard file. Or a spade bit for that matter. I tend to fill my tool box on an as-needed basis. I've been a homeowner for 25 years, a light wood furniture restorer for 35 or more. Never found a need for either of those tools (yet).

Thanks again.

 

[Freeman Keller]

You assume I already have a bastard file. Or a spade bit for that matter. I tend to fill my tool box on an as-needed basis. I've been a homeowner for 25 years, a light wood furniture restorer for 35 or more. Never found a need for either of those tools (yet).

Thanks again.

I assume that someone working on a guitar has basic tools or will buy the things they need. A 1" spade bit and a 10 inch mill bastard file are about seven dollars each at Lowes, just part of DIY lutherie. I've done enough of these that buying the right tools has paid for themselves long ago.

 

[telel6s]

So I finally got around to finishing this up. I tried to file the back side of a spade bit to make a pull cutter as suggested earlier in the responses. Couldn't get it to work. Whether using just a hand file or a Dremel blade sharpener I couldn't get enough of an edge for that to cut anything (clearly, I was testing this on scrap wood before attacking the guitar).

What I ended up doing was get a flexible drill extension and attached a step bit that I already had. This solved a few things for me by (1) being able to easily access the inside of the guitar body, (2) I was able to line up the step bit by feel with the existing jack hole even though I couldn't see anything, (3) at low RPMs, you can feel the step bit "click" to the next size so I could control it without drilling out too much of the end block. I ended up going two steps farther, but checked after just one step.

End result is the whole thing now sits deeper into the end block and the jack protrudes just enough more so that cables click securely into place when inserted, including right-angle plugs which I prefer. Everything is nice and solidly attached.

Thanks again for all the suggestions above.