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I am considering counterboring the washers on the face of the head for Schaller or Gotoh tuners.

The problem is that over time as the string pressure pulls the front of the washer digs into the lacquer on the face of the head and puckers the lacquer.

Obviously you can use a commercially made counterbore-Graingers? McMaster Carr? ????????

Any other methods?

Brad,
I use a Dremel and base to cut the counterbores freehand. First picture.
Sometimes I drill the holes in the headstock veneer before gluing it to the head. Second picture.
I like the look, and it may add some stability to the tuner shaft.
Dan

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Wah-wah-wah-wah
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I use the fixture described in David Russell Young's book. Simple block with a short 10mm pin centered under a drill press spindle. Tuner hole placed on the locating pin, the CB is cut with a bottom cutting end mill.

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Ken Cierp

http://www.kennethmichaelguitars.com/

Oh yeah, that book. I took a look at it again, he actually puts another washer under ( in the recess) the washer so the top washer sits flush.

I use these... problem solved. http://www.stewmac.com/Luthier_Tools/Ty ... l_Bit.html

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It will probably be alright.

I use this, also from stewmac. When it wears out I will probably get what Greg has.



The above bit is cool though. As long as your headstock is 15-16mm thick, counter boring from the back until the pilot guide is flush with the face (in other words, hold face down on bench and drill til it stops) the depth is correct automatically.

Those Stew Mac tools both address a different issue (and frankly a situation, tilting tuning machines which I have never seen or had a concern). I believe the problem is simply preventing the washer from peeling away the finish by adding a CB pocket. BTW I agree its a very nice simple to produce custom feature.

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Ken Cierp

http://www.kennethmichaelguitars.com/

A long phase of my life was plagued with tilting tuners pulling up the finish, the problem is very real.

Guess I have been lucky -- but to me the Stew Mac illustration defies logic if the base hole is the correct size and the back plate is secured with a screw how can that entire machine tip as shown? However, I can see how the string "post" could move and tilt toward the bridge under tension when the nut is running out of threads, so in that regard I certainly stand corrected.

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Ken Cierp

http://www.kennethmichaelguitars.com/

I just drill an 2mm starter hole though then drill from the front to match the bushing thread OD and from the back to suit the tuner stub.
Not countersunk. but the bushing is fully supported.

Until I started using the Stew Mac tool I had a consistent problem with the washers causing a milky dimple in front of the tuners due to string tension pulling on the tuner. I've never had it happen since.

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It will probably be alright.

I have had the same problems so after 40 years its time to do something about it.

I think it has a lot to do with the type (and thickness) of the finish. The illustration is showing an exagerated view of what is happening. It's just enough downward string pressure to pucker the lacquer -in my case Nitro.

+1, minus the pilot hole. I use a Lee Valley HSS brad-point bit for the bushing side, and a HSS twist bit for the back side.

Using a pilot hole avoids having to drill through the headstock with either large bit so no breakout coming through, and I have a centre so I can use brad point bits from the back first and then from the front to meet.

I'm guessing a pilot hole followed by a Forstner bit to relieve the headstock veneer, and then drill for the tuner shaft, would go some way to getting the headstock counterbored for the washers, and retain concentricity. Could also clamp the headstock into position and not move it till both the counterbore for the washer and the tuner shaft were drilled. No?

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Peter Havriluk

I've used a piloted counterbore. like this:
http://www.mcmaster.com/#counterbores/=11u4m9q
Then I made a UHMW "washer" that fits the shaft of the bore and locks with a set screw. That way there is no measuring just drill until it stops. Perfect every time.

Not a counterbore response, and more like the StewMac solution, except I'm a cheapie and don't want to fork up the $$$ for a bit. So I click on the Amazon link above, do a search for
"Atoplee 4-12mm TI-Coated HSS Spiral Grooved Step Drill Set,Triangle Shank"
And order a couple more to add to the 1 that I've had over a year.

I grind down the 12mm section, and just use the 8 and 10mm sections for tuning machines. Fits my Hipshots like a glove. I'm sure the StewMac is a tighter fit, but even this makes a LOT of difference in how the machine tightens up.

And did I say I clicked the Amazon link above?

So if all screw-down tuners generate this issue, perhaps this is more a case of poor tuner design, rather rather than an installation issue? I realize - as an example - that the Gotoh Delta and other 'contour' tuners are very fashionable right now, but are there other tuner options beyond the Schertler open backs that do not invite the issues associated with the design?

More to the OP's point, we use a modified (smaller cutting spurs) Fuller counter-bore with depth collar for this sort of task. If the central hole is bored accurately, the counter bore will be accurate as well.

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A constellation only takes shape when one maps the whole.
- Beth Brower