I've had this Martin 0-18T (tenor) guitar hanging around The Dungeon for a couple of years. I'm trying to play tenor guitar more, so I figured it was about time I took a look at what it needs to be playable.
Plus it's really dirty.
Hopefully I can clean all this up.
My guess is it was stored in a semi-dry, but still somewhat humid basement, hence the corrosion on the tuners. And the humidity actually prevented cracks.
It may be that the seam opened and what we see here is dirt that's gotten in. I'll know more as I clean it.
In any event, I'm not worrying about the integrity of the joint. It's solid.
I took a weak mixture of Simple Green and wiped it down. I'll clean and polish it later, but I wanted to at least get the surface dirt off while I work on it.
The guitar needs three major repairs:
1 - a neck reset (pretty typical for an old Martin).
2- the neck has a bad backbow and needs to be straightened (more on that later).
3- a refret. I probably could salvage the original frets, but I want to put in frets with a larger tang to help the backbow issue.
So I'm going to do the reset first, then tackle the neck/fret issues.
With the guitar tuned to pitch (holding my breath with those grungy tuners and ancient strings), I measured the distance a straightedge placed on the frets falls under the top of the bridge. I used to do this with a small ruler, but a while back I sprung for this helpful gauge.
You get a direct readout of the distance instead of trying to eye tiny marks on a ruler. In this instance, the distance is .130 inches.
With the tension removed (strings loosened or removed), I then measure this same point. The top will deflect a bit - in other words, it will move downward with no tension.
Depending on the guitar, the string gauge, etc., this distance could be substantial. In this instance, it was only 3 thousandths of an inch (.003). It's a small guitar, and only has 4 strings, so there isn't a lot of deflection (tension). But on a larger six-string guitar, the deflection would likely be higher.
Why is this important? Well, the gauge is not totally necessary, but it helps us get a much more accurate angle on the neck after the heel is cut and the neck is reinstalled. If we were able to raise the top of the guitar up to the exact height it would be under string tension without the strings on it, we'd be simulating that tension and thus be able to judge the exact correct angle for the neck!
I have a brace jack that I've mounted to a piece of scrap wood. I've found the jack tends to dance all around the inside of the guitar otherwise, so this keeps it in place while we put it in position.
The piece of wood can span a couple of back braces inside the guitar, and the jack can be positioned right under the bridge where we measured the deflection.
Now the top of the guitar is at the same height it would be if it was strung to pitch.
The serial number indicates it was made in 1931.
Martin has kept meticulous records. If you write them, they can generally provide the day the instrument left the factory!
Try that with a Gibson or Guild.
They came off easily, except for one which just wouldn't come out of its bushing. So I put some PB Blaster between the tuner's shaft and the bushing. It took a day of small applications of Blaster to get the tuner to come out.
They were all originally very stiff, but now they turn easily.
Unfortunately, there is some pitting on the chrome buttons which can't be removed. But at least they work well and just look like old tuners instead of being green and corroded.
What a difference, huh? Compare this to the picture above. I have high hopes for the rest of the finish now.
You can see one bushing came off. I have since reinstalled it with a couple drops of thin CA.
Next, we'll measure for the reset and get the neck off.
All posts in the 1931 Martin 0-18T Restoration Project:
- 1931 Martin 0-18T Guitar Restoration and Repair, Pt. 1 - This page.
- Neck Removal on 1931 Martin 0-18T Guitar: Restoration and Repair, Pt. 2
- Trimming the Neck Heel for Reset: 1931 Martin 0-18T Restoration and Repair, Pt. 3
- Shimming Guitar Neck Dovetail and Finish Chip Repair: 1931 Martin 0-18T Restoration and Repair, Pt. 4
- Caul for Heat-straightening Guitar Neck: 1931 Martin 0-18T Restoration and Repair, Pt. 5
- Reparing Acoustic Body Cracks: 1931 Martin 0-18T Restoration and Repair, Pt. 6
- Making a Tortoloid Pickguard: 1931 Martin 0-18T Restoration and Repair, Pt. 7
- Heat Straightening Bowed Guitar Neck: 1931 Martin 0-18T Restoration and Repair, Pt. 8
- Fret Marker Installation and Filling Fingerboard Chips: 1931 Martin 0-18T Restoration and Repair, Pt. 9
- Compression Fretting to Correct Upbow: 1931 Martin 0-18T Restoration and Repair, Pt. 10
- Completed 1931 Martin 0-18T: Restoration and Repair, Pt. 11