Tuning Machines on Martin Kit

[naccoachbob]

John or anyone who might know, I'm about to drill the holes in my headstock for the Martin kit I have. I do not have any documentation on the size of hole that I need to drill.
Absent that information, where should I take the measurement on the tuning machine to get the proper hole size?
Is or was Martin using metric or fractional sized machines?
Here's where I took the measurement. I got 25/64" there, 9.93 mm, and .39 decimal inch. The machines say Martin on the back.



Thanks,
Bob

[tippie53]

you need to get a drill card , there are many different tuners so there are no set sizes. Most tuners will use a 1/4 in post but you have the furrel and base. I would say make a test hole for the best fit.
mark your centers and drill a small pilot hole. Figure your countersinks , I am sure you will figure it out real fast.

[naccoachbob]

Ok, I got out all the brad point bits I could find, picked out a small piece of cherry that was looking for work and discovered this. I have a 19/64" bit of all things. The ferrule (if that's what I think it is - the part that screws into the body of the tuner) will screw in nicely.
So, I'm assuming that they use fractional inches. I used a 3/8" bit and found I could push the body in about half way. It took a good bit of effort. I don't want to use that much effort and risk breaking the headstock or scratching it from exertion, so I'll find a 25/64" bit somewhere.

The remaining question is this: Should I run the 19/64" bit thru the headstock, and come from the back with the 25/64" bit and drill it the 5/16" that it needs to go to seat properly? Or is this overkill? Should I just use the 25/64" bit thru it all and leave it at that?

Thanks,
Bob

[Ben-Had]

Does this set have press fit bushings?

[naccoachbob]

No, if this is what you're saying is "press fit": http://www.stewmac.com/shop/Tuners/Tune ... hings.html

Here's what I have:




Bob

[Ben-Had]

I drill those straight through with a 10 mm bit. I have a Lee Valley HSS lipped brad point bit that cuts super clean. I place piece of tape on the back side and use a backer board and have virtually no tear out. If there is a little the tuner hides it. A little expensive but worth it IMHO for this job.

http://www.leevalley.com/US/wood/page.a ... 2240,42247

[johnnparchem]

I drill those straight through with a 10 mm bit. I have a Lee Valley HSS lipped brad point bit that cuts super clean. I place piece of tape on the back side and use a backer board and have virtually no tear out. If there is a little the tuner hides it. A little expensive but worth it IMHO for this job.

http://www.leevalley.com/US/wood/page.a ... 2240,42247

plus one on straight through with 10mm. There is no need to be fancy as the bushing is straight and screws on.

[naccoachbob]

Thank you all. 10mm bit it is. No two-stepping for me (and I'm from Texas). Now I gotta find one.
For some reason I thought I had one from previous guitar builds, but it must be hiding.
Much appreciated.
Bob