Holes for installing tuners

[Island Jim]

I have a question for you builders. Do you drill two size holes when installing tuners with bushings, one to just fit the peg and then a larger one for the bushing? I would love to have a single drill bit that would work for both in one pass, have you seen one like that?

 

[rb4player]

I drill single hole to fit bushing when installing Grover’s.

 

[sequoia]

I drill 4 10mm holes and then 2 1/16 inch holes for each geared tuner. I use a tape stop on the 1/16 bits so I don't drill too deep. Once, long ago, I drilled right through the peghead and out the other side. That was the kind of bad moment that can happen building ukuleles. !#&&@#!!! S--t! As I remember, I had an ebony veneer on that peghead so I filled the hole with ebony dust and used black CA glue and the hole disappeared and nobody is the wiser except me. Sometimes we know where the bodies are buried. Oh, and use drill stops on all your bits. You will be happy you did.



You can buy these from SMD which are ridiculously expensive ($11.00 apiece???) so I just wrap painters tape around the bit at the depth I want.

 

[Pegasus Guitars]

Yes, you should drill 1 size hole for the bushing and another for the shaft. It stops the posts from leaning over and binding under string pressure. Stew-Mac sells a 2 step drill in a number of sizes. They aint cheap, but it is soooo nice to have the right tool for the job.

 

[Island Jim]

Thank you all for the answers. I just found that Stew Mac bit which is exactly what I was looking for, I felt that having the bushing size hole to support the shaft would eventually cause problems. I will save my money and order it.

 

[Timbuck]

I used to do 2 different size holes but now I drill just one.

 

[ProfChris]

I drill a small pilot hole right through, the same size as the brad point of my bits. Then I drill from either side, using different sized bits so the post hole is smaller than the bushing hole. Prevents blowout and matches my cheapskate philosophy!

 

[jupiteruke]

I found some counterbores at McMasterCarr that do a good job for Grover tuners. I use the 9.13mm body with a 5mm hole. The counterbore fits the tapered bushing well, and the 5mm hole is easily drilled out to 6mm for the tuner post. Since the drill hole and counterbore happen at the same time everything is perfectly aligned. Not cheap but pay for itself in ease of use and accuracy. See https://www.mcmaster.com/products/drill-bits/counterbores-2~/

 

[rb4player]

Is this discussion around sealed tuners where the gear housing is larger diameter than the bushing? I could understand the second diameter as more elegant in that case. If the bushing is the larger diameter vs the shaft only, I have trouble imagining the utility, particularly for nylon strings. Certainly not an expert compared to many here, but millions of open geared Grover’s installed on steel string guitars with a single hole diameter matched to the bushing. I’m here to learn.

 

[rb4player]

Best practices likely vary with specific tuner type.

Chuck Moore specifically addressed Grover Sta-Tites (what I use) in this thread.

https://forum.ukuleleunderground.com/threads/grover-geared-tuning-machine-installation.68574/

 

[1bad914]

One hole size. Never had an issue on any instrument I built and used that style of tuner.

 

[Pegasus Guitars]

There probably is no right way or wrong way of doing the tuner holes, except that the stepped hole is the right way! Like most everyone I suppose, I started my building doing the single size hole, generally the size of the bushing. When I started doing better finishes, I had a couple of instances of sideways pressure on the bushing causing the lacquer to bubble at the nut side of the bushing, and I did experience some excessive friction on the shaft if everything was not perfectly aligned. After a builder clued me in to the stepped hole, that issue went away. For tuners with screw in bushings I've seen some builders go as far as having 3 steps. One for the tuner rear housing housing, one for the shaft, and a third for the washer under the front bushing. I think this is done specifically to deal with the lacquer bubble issue. I've never tried that. If you have a oil finish, or are not going for a pore free gloss finish, or the bushing is not out of alignment with the shaft there probably won't ever be an issue. Even though many commercial ukes and guitars use the single hole style, I never use those instruments as a model for how I should build. In the real world, none of this matters to anyone but the builder. If you are comfortable with your style, and good enough is goof enough, then you're home free!

 

[Island Jim]

It seems opinions vary, some highly respected Luthiers do it both ways. I feel more comfortable with a stepped hole for Grover type tuners. I tried the Prof Chris method with a small hole drilled straight thru and then brad bits from both sides, a little fussy but it worked well. A stepped drill with a brad point would be ideal.

 

[Timbuck]

with stepped holes I found it was a pain to knock out the bushes if I wanted to do more work on the headstock.

 

[Island Jim]

I had to pull bushings out of a headstock last week, I used my flush ground end nippers and was able to get a grip on the edges. They came out with no damage.

 

[Titchtheclown]

I use a cheap step drill bit. The 4 to 12mm in 2mm steps (leftmost in picture) seems to work with the 6 to 8 step for most open geared tuners that have a bushing and the 8 to 10 step is almost perfect for most sealed tuners. I just had to take a grinder to the 12mm lip so it now is 10mm to the depth required for the sealed tuner.
Sometimes a drop of glue is needed on the bushings and sometimes I need to wiggle to get the hole slightly wider on sealed tuners or file out the 6mm hole to 1/4 inch.