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Hate to go to a bunch of trouble that ends up with no upside - - - tuner holes in the peghead. Tuner body shanks are 10 mm. The shaft nut is 8 mm. The shank fills most of the hole in the peghead. It's a bit of a nuisance to drill through at 8mm and drill a 10mm hole save for that little bit at the top to positively contain the shaft nut. I've done this drill/counterbore dance on five guitars so far. Bit is it necessary? What bad stuff happens when I drill 10 mm all the way through and dispense with counterboring? Love to avoid a step I don't really need to do.

Thanks!

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Peter Havriluk

I believe in drawing everything out, that is different on the guitar, before I start work. It has saved me more than once.
This is for a current build:

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Joe Beaver
Maker of Sawdust

Joe, thanks for taking time to respond. But I think 'drawing everything out' doesn't speak to my question.

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Peter Havriluk

If I understand the question - I use this:


https://www.stewmac.com/luthier-tools-a ... amers.html

and then a typical step drill or this on the back:

https://www.stewmac.com/luthier-tools-a ... eamer.html

If I’m getting what you are asking, my understanding is you don’t want the tuner post to be in a larger hole with only the bushing keeping it upright. The bushing will dig into the finish / headstock because of the pressure trying to hold the tuner post against the string tension.

Is that what you meant?

Hope that helps.

Brad


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If you don't counterbore, the washer under the bushing creates an indent in the headplate due to the tuner tilting toward the bridge. It can cause the finish to separate from the wood and chip in some cases. I just checked on one I did with African blackwood headplate and shellac finish, and it has a very slight indent, but I don't think it will ever cause any trouble. Softer headplate would indent further, but a thin shellac finish will never chip, so it still probably wouldn't cause trouble aside from possibly needing to tighten down the bushings at some point if the washers ever get enough wiggle room to rattle.

It certainly is more proper to support the bushing from the side so the tuner doesn't tilt in the first place. I was always too much of a cheapskate to buy one of those StewMac tools, but I do have some cheap step drills now which I can try next time I build one with closed back tuners.

Peter,
Your right, posted on the wrong thread. My mistake

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Joe Beaver
Maker of Sawdust

These sealed tuning machines can certainly cause finish damage if they become loose or if they’re over-tightened. Having said that, I can’t recall when I’ve ever seen a counterbored hole on any factory guitar. It’s usually just a straight 10mm hole.

The Stewmac counterbore bit is on my wishlist:
https://www.stewmac.com/luthier-tools-and-supplies/types-of-tools/drill-bits/1-step-peghole-drill-bit.html

I’ve actually had more finish damage caused by tuners with press-in bushings.


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I hadn't noticed that counterbore bit before. I've been using their rear peghole reamer to drill from the back after drilling a 5/16" hole from the front side. https://www.stewmac.com/luthier-tools-and-supplies/types-of-tools/reamers/rear-peghole-reamer.html What I like about the reamer is that it automatically counterbores to exactly the right depth. It's impossible as far as I can tell to mess that up. It looks to me that with the 1-step peghole drill bit, you would have to pay close attention to that.

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Once in a while you get shown the light in the strangest of places if you look at it right - Robert Hunter

I use one of these: https://www.amazon.com/Irwin-11102-Unib ... B00075RFZG

Drill an 8mm hole from the top side, flip it over and use this step drill from the back side. I use the 12mm step as a depth gauge. I like to go a tiny bit past, leaving a nice clean chamfer. Does a flawless job and doesn’t cost $85.

M

To be clear I’m using a drill press for these operations.

Thanks, everybody. I got myself a fine education in tuner hole drilling. This is wonderful.

And Amazon says I'll have the Unibit on Monday. So I have all day Sunday to drill a dozen 8mm holes.

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Peter Havriluk

I still the small diameter hole then use a counterbore. Specific to the tuner


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The Stew-Mac rear counterbore is worth the money 1000%.

Drill your 5/16” hole through from the face on the drill press, turn it over and counterbore by hand. Takes under a minute for the rear counterbore and bit will last your lifetime.

Ed, I think a problem for hobbyist builders (like me) is becoming topheavy with tools that are costly and single-use. Very different from a production environment when a tool might be used on an instrument a day. A builder who can save a half-hour on an operation he does once a day by buying a tool is in tall cotton. An amateur, he'll be using a tool three times a year. He's needing to justify the purchase (like stew-mac's eighty-dollar counterbore). I'm very happy to be able to do a fussy job with a twenty-dollar step drill. For me, that's moving up in the world.

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Peter Havriluk

Great for drilling your endpin jacks too...

Here’s how I did it pre stewmac tool..

1) drill through with 1/16 bit

2) drill from back to desired depth with 10mm brad point

3) drill front with 5/16” brad point

The brads follow the 1/16” pilot hole...

Now I have two techniques to get this job done. Thanks!

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Peter Havriluk

Just drilled all 12 tuner holes using the 'Unibit' technique. Lawd 'a mercy, was that slick! I'd piloted with a small number drill, drilled the 8mm holes through from the backside, then used the Unibit as a counterbore to go to 10mm for the tuner body. Sweet! Everything was painlessly concentric, the tuners fit so nicely. And as advertised, after I'd drilled a little chamfer for the tuner body to set solidly on the peghead, the hole depth was just right for the tuner, no measuring, no fussing. Best eighteen bucks I ever spent on geetar tools.

Michael, thanks very much!

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Peter Havriluk

You bet!

Just thought I'd mention that propeller reamers for model aircraft can be handy as well.

I use one to clean out finish from tuner holes, as I'm a bit uneasy about using a drill mounted unibit.

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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.

I put the unibit in a hex bit driver handle to clear finish manually.

M

Great if you have a hex unibit, mine isn't.

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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.

I've always just drilled 10mm holes through and called it a day. But that does seem the proper way to do it. I've just never had a problem doing it that way before.

This is one of those little tasks that factories could take a 10mm shortcut on and nobody would be the wiser, but when you (I) make one at a time and puzzle over the details, sometimes we can find the corner the factory cut. It may well be gratuitous effort for no usable benefit, but it feels nice to do something mechanically right. Don't take much to amuse me sometimes (my wife says it happens more than I think).

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Peter Havriluk