There are just a few things left to do on the Martin 1T. One of them is to install new tuners.
The tuners on all these old Martins have lasted a long time and work well, but they do have one issue that's not easily corrected. The picture to the right illustrates it.
If you look at the tuner button at the bottom, you'll see it was molded from one piece of plastic. The part that slides into the bushing is a square shape. The bushing also has a matching square in it - this is what drives the post when you turn the button. The problem with the design is that the square drive is made of plastic. Over time, when the button gets loose and slips, the plastic turns in the bushing and the square edges are gradually worn away to the point where the button will just turn no matter how tight the screw is, because the corners have become rounded.
I "fixed" one of the tuners on my ca. 1929 Martin by just gluing the button to the bushing with JB Weld. However, that's only a temporary fix - the button will slip again over time.
When one of the tuners on this other (ca. 1940) ukulele started slipping, I decided to replace it with some new Waverly tuners. This is a new design friction tuner, not geared, but with some improvements, yet resembling the old friction tuners.
You can see the Waverly on the right also 'exploded.' The bushing has a slot that the button fits into, and the button is ebony. There is also a spring to maintain tension, which means it should not require tightening as much as the old Grovers.
However, the Waverlies (Waverlys?) are a bit smaller, and as I found out, require a little finesse when putting them in an old Martin.
Since I wanted the tuners to look right, I got the proper 60 degree (for the bottom section of the tuner where it meets the underside of the peghead ) and 100 degree (for the top side) countersink bits. You see them here - I got them from McMaster-Carr.
Here's where a little measuring FIRST comes in handy. I eyeballed the tuners and the headstock and assumed they'd fit perfectly. Never assume. Always measure!
So after assuming they'd go in with no problems I set about making the countersinks.
So I made the same chamfer on the top of the headstock, and used the 100 degree bit for the back.
The bushings fit perfectly and looked good.
However, the thickness of the headstock is about 1/32 of an inch too thin for the bushings to sit down perfectly in the chamfers! In other words, when I put a tuner in and tightened it up, there was vertical play in it.
I really wanted the bottoms of the tuners to fit well, so I decided to use some plugs in the top of the tuner holes to make a new surface for the bushings to sit in.
The plugs are about half the height of the holes - and they give the bushings the proper height to sit on.
That sign painter's tape works great to safely mask off a surface you want to protect.
The shade of the stain is 'Red mahogany.' Not even close. But dark is good.
They'd look great in a chamfered hole, but I just don't have enough thickness to work with. Still, they don't look bad - from the top they look great.
You can also see how the ebony button fits down into the bushing. This is a much better design than the old style.
They'd work really nicely on a new build. Now I just need to finish the ukulele so I can try them out.
Update April 20, 2014: I've replaced these tuners with some Gotoh UPT Geared Planetary tuners.