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Do any of you have any tricks you could share for avoiding tear out on the inside of the end block when drilling for an endpin jack? I don't have a problem making a clean hole on the outside using a brad point bit, but I'd like to have a clean hole on the inside, too, especially on guitars with side soundports where the end block is visible.

I know that one technique is to drill a smaller hole and then ream it with StewMac's endpin jack reamer, but I'd rather not invest in that tool if I don't have to. The usual method of clamping a block to the back side of something to avoid tear out on the exit would work if I had a way to clamp a block in there, but I haven't thought of a way to do that. Using some sort of counterbore on the inside would be another way, I suppose...

Thanks in advance for your ingenious methods -

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Todd Rose
Ithaca, NY

https://www.dreamingrosesecobnb.com/todds-art-music

https://www.facebook.com/ToddRoseGuitars/

I've never tried it, but an idea. If you could place the "anti tearout block" against the endblock, then use a turnbuckle placed between it and another block placed against the neck block, would that work? Kind of like using a turnbuckle and blocks in the waist area while the guitar is in the mold...similar to that. Just an idea. What do you think?

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Brad Tucker

Woodcraft sells these drill bits, Cord? Cort? and they do an excellent job at making unsupported holes clean on the inside. They are reasonably inexpensive.

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Brock Poling
Columbus, Ohio
http://www.polingguitars.com

I really like that stewmac reamer...

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Jordan Aceto
Ithaca, NY

I second the StewMac reamer. It's a few$$$ but it makes fitting a pickup totally painless. If you have to countersink the inside for a thick tail block go to theyardstore.com an aircraft tool outfit. Do a search for "reverse spotfacer"
Terry

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It's not what you don't know that hurts you, it's what you do know that's wrong.

Thanks, Brad, Brock, Jordan, and Terry, for your responses.

Brad, I was thinking about something along the lines of your suggestion, and it might just work.

Brock, I found "Colt Twinland" brad point bits from Germany in the Woodcraft catalog, presumably the ones you're referring to. Thanks for the recommendation. I will probably get a few of those for various purposes.

Sounds like the StewMac reamer is really the cat's pajamas for this, though, so I'll probably bite the bullet and pick one up. Or maybe I'll just see if my cats have a spare pair of pajamas they could lend me...

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Todd Rose
Ithaca, NY

https://www.dreamingrosesecobnb.com/todds-art-music

https://www.facebook.com/ToddRoseGuitars/

The StewMac reamer is pretty hard to beat. If you're starting from bare though (rather than enlarging a tapered endpin hole), you can get by with a 12mm forstner bit. Sometimes they can cut easier in hardwoods with a 1/16" pilot hole, but the pilot shouldn't be any larger than perhaps half the diameter of the forstner's pointed tip, and you still have to go in slowly when you get the the inside to avoid tearing.

If you anticipate doing this more than once or twice however, the StewMac reamer is a great tool to have.

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Eschew obfuscation, espouse elucidation.

It would be easier to use the block on the inside if you drilled the hole before you glued on the top. If that can fit in your build schedule then it's a really easy solution.

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Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

Thanks, David and Bob.

David, I appreciate your tips for using a forstner bit for the job. Your endorsement of the StewMac reamer, along with Jordan's and Terry's, is also very helpful.

Bob, I'm thinking about making some changes in my process of putting a guitar together - namely, putting the butt wedge in before closing the box - which would enable me to drill the end pin jack hole as you suggest on guitars I'm building. I might do that...

Anyway, the guitar on my bench right now had an ebony end pin that I couldn't pull out. I believe it was glued in. Next time I encounter one of those, I'll bug you guys for tips on pulling a stubborn end pin. What I did, anyway, was saw it off and scrape it flush. So, now I'm basically starting over from a no-hole situation. I'm thinking I'll get the StewMac reamer, which, according to the info on the StewMac site, tapers to 1/4". So, I figure I'll drill a 5/16" hole with a brad point bit and then ream it to 15/32".

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Todd Rose
Ithaca, NY

https://www.dreamingrosesecobnb.com/todds-art-music

https://www.facebook.com/ToddRoseGuitars/

Thanks, Todd. I'll check that out, too.

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Todd Rose
Ithaca, NY

https://www.dreamingrosesecobnb.com/todds-art-music

https://www.facebook.com/ToddRoseGuitars/

Todd;
Electronics are so often used now I started pre-drilling my butt blocks before gluing them to the sides.
I do not go all the way through the block just 3/4 of the thickness.
From the inside !
I center the hole in the block and my butt strip is centered so I always drill into it from the outside when i need to.

Mike

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Mike Collins

That is a great bit! I have a local repair guy here who uses that all the time on finished guitars for installing the electronics end pin jack. 1/2" is standard I think. He said it doesn't chip out at all. But I've never used one, only going by here-say. You can get one here for $12 http://www.amazon.com/10231-Unibit1-8-Inch-2-Inch-4-Inch/dp/B00004THYX

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Tracy
http://www.luthiersuppliers.com

I don't see how you could clear a 15/32" hole with that tool all the way through, unless you were to grind down the 1/2" step to 15/32".

A 1/2" hole can work, and many people use that, but I strongly recommend against it. That seemingly small 1/32" comes out of a very key point, and can make a real difference in how securely a jack can be fit in my opinion. Maybe I'll post some pics later tonight showing the reasoning behind this.

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Eschew obfuscation, espouse elucidation.

I've been using the Irwin Stepped-Ream for years.

Sure beats changing bits several times.

The K and K pickups and Stew Mac's Fishman Switchcraft work great.

Here is the detail: 15/32" diameter, for 1/2" mounting hole. Instructions included.



I love the fact that the Irwin gently shaves like a plane, rather than grabs like a regular bit.

I use a forstner bit to do my tuning machines and it might work well for this job too. Just something about scribing a cut along the perimiter of the hole that works.

I'd like to hear David's reasoning for the exact hole. I have added a round or two of cellophane tape to any that are sloppy. But I don't remember doing it with Switchcraft Fishman jacks.

One thing you do have to do is chuck up short on the shaft of the Irwin after getting most of the hole cut, that allows you to penetrate and complete the hole.

One more trick in the bag: Does anyone have problems with the endcap coming loose over time? I have, it's not easy to tighten without scratching. So, on the final install, I drop some pva glue on the threads, not much, just enough to be a wee bit binding. Seems to work for me.



Okay, I followed the link and here is the pic. Chuck up on the whole thing, drill up to chuck, stop, re=chuck on the last 5/16 to break through cleanly. That's it.

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http://www.dickeyguitars.com

I do what David does, except I drill all the way through and end up having to ream out dried glue. Drilling within 1-2mm of "through" sounds better to me.

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The member formerly known as erikbojerik....

Now, that's a very interesting idea, Mike. I'm amazed, though, if you can hit the pre-drilled hole dead-on when you go to drill it from the outside.

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Todd Rose
Ithaca, NY

https://www.dreamingrosesecobnb.com/todds-art-music

https://www.facebook.com/ToddRoseGuitars/

todd,

here's what i do. i've installed a few d-tar's in the last year and they require a 15/32" hole. i do all the drilling from the outside with a brad point the right size. the drilling is all quite slow. when i can see that i'm more than half way through the tail block, i reach in side the guitar and put up a sacrificial block (about 3"x3"x3/4") against the inside face of the tail block. it's a bit of a reach, but you can just kind of tip it into place. i then hold another stick or piece of dowel against that block, and reach around with my cordless drill to finish the job. drilling slowly again, i'm essentially pressing my two hands together. your left hand will feel it when the bit is through to the loose, sacrificial piece. no tear out for me, as i can see through my sound port.

good luck.

phil

That'll work. Sounds like a good alternative for half the price.

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Eschew obfuscation, espouse elucidation.

I have an index of straight reamers for stepped enlarging of various holes. I thought it a futile suggestion for endpins though, because if you don't already have them the cost of all the reamers would far outweigh the cost of StewMac's endpin reamer. I hadn't thought about using a 15/32" final reamer in conjunction with the Unibit, which I guess when you look at it is nothing more than a dozen straight reamers stacked on one shaft. That's actually a great idea, especially considering this certainly won't be the only thing your Unibit gets used for. Plus it seems the stacked conical nature of the Unibit would make it easier to keep alignment when enlarging a tapered hole than using a series of individual straight reamers.

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Eschew obfuscation, espouse elucidation.

Phil, thanks for sharing your method.

Todd and David, thanks for your follow-ups on the reamer options.

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Todd Rose
Ithaca, NY

https://www.dreamingrosesecobnb.com/todds-art-music

https://www.facebook.com/ToddRoseGuitars/

Todd;
I drill a small( 1/4") pilot hole first .From the outside.
Then use a reamer to enlarge the outside hole to the desired width .
No tear out and it's done in a New York minute.

Hey -how's the Flamenco restoration going?

Mike

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Mike Collins

Todd,

I posted this once before but perhaps it's worth another showing:



I rigged this up when I had an end block that was too thick for my strap jack. First I made the half inch dia. hole then I joined the three quarter inch drill bit to the half inch drill bit as shown in the picture. I put the joined drill bits through the drilled hole from inside the guitar, attached my drill and ran it in reverse while pulling back. The half inch drill bit kept things centered while the three quarter bit made the counter sink. Worked very cleanly and cost me nothing as I had the drill bits on hand.

Pat

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There are three kinds of people:

Those that make things happen,
those that watch things happen,
and those that wondered what happened.

Thanks for elaborating on your method, Mike. As for the flamenco, well... it's waiting its turn. Haven't had time to work on it.

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Todd Rose
Ithaca, NY

https://www.dreamingrosesecobnb.com/todds-art-music

https://www.facebook.com/ToddRoseGuitars/

Pat, thanks for posting that. That's cool! Great idea.

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Todd Rose
Ithaca, NY

https://www.dreamingrosesecobnb.com/todds-art-music

https://www.facebook.com/ToddRoseGuitars/

Pat--A fine example of an elegant solution!
How did you join the two? Is that a screw head I see?
I would have guessed too hard to drill holes.
Thanks
Nelson Palen