Like all interesting things, this repair started out simply enough. I saw my friend Bill down at the North Arkansas Fiddlers’ Convention, and he said, “The bridge is just starting to pull up on this old guitar,” as he handed me his 1944 D-18. I didn’t think regluing the bridge would be any big deal, then Bill said, “The bridge has been off before. And there’s a hole through the top underneath it that you could put your little finger in.”

I looked more closely, and Bill says, “You know, the bridge has been reglued a few times since I got it in the eighties.” I felt around the top a little more carefully and realized that it was thin and yielded easily to light thumb pressure. Looking inside, you could see where the X brace legs had been drilled through and extra bracing had been added alongside the damaged sections. It seemed like the best course of action was to remove the back and replace the top braces that were so weak. Once I got to work on the guitar, the first tasks were to remove the bridge and neck.

The top of a guitar, under the removed bridge
The bridge has been off many times, and the runout in this area is significant.

Under the bridge, I found that there was not much wood left, and what there was showed significant runout, which makes it hard for glue to make a good bond between the bridge and top. I called Bill again, and he told me that when he first got the guitar, it had “an old piece of 2×4 for a bridge, and a knitting needle was laid across it for a saddle.” I’m guessing that the pine wood bridge was bolted down, too, explaining the bolt holes in the X brace legs. Obviously, the bridge had always been a problem. The bolt holes, the extra bracing, an oversized replacement bridge patch, and a bridge doctor had all been used to try to keep the bridge on. After talking it over, we decided that, since this guitar was meant for playing, and had been modified extensively in other ways (for instance, a truss rod was added to the neck by routing from the backside of the neck, like a skunk-stripe electric guitar neck), the best answer was to replace the top with a mechanically excellent red spruce top from our friends at Old Standard.



I decided to replace the top without replacing the delicate tortoise celluloid binding and purfling. So, I made a new top plate and matched the soundhole and rosette to the original top, then used the guitar body as a pattern to guide my binding router so that I could size the new top to fit inside the existing purflings. Once the top was trimmed to size and shape, I used a purfling router setup to cut the old top off.



Once the top was off, I scraped the linings and the inside edge of the purfling to make a clean ledge for the new top to drop into. I also braced the new top, taking it back in time about 8 years, to the mid 1930s. In the late 1930s, Martin closed the X brace down and moved it back toward the bridge, presumably to put more structure under the bridge and prevent some warranty repairs. In rosewood dreadnoughts, a more closed-down, backward-shifted X brace sounds crisper to me (particularly the compromise shift that Martin started using in the late 1950s that was somewhere between the early 30s forward position and the late 30s far-back position), but, for mahogany, I like the earlier, looser tops. While I had easy access, I fixed several cracks in the sides and back. Once everything was ready to go, I closed the box again–and does it thump!




Now that the body is back together, it’s time to fit the neck joint again, correcting some problems with the alignment. This neck needed to go way back to allow the right string height over the soundboard, so I’ll need pretty thick mahogany shims to fit the dovetail. When I took the neck off originally, I noticed that the tenon was cut off-center on the neck, and that the factory made up for it by routing the neck pocket off-center, too (or vice versa). It complicates the neck reset slightly, but mostly is just a curiosity. As is the large wood screw that was screwed through the body’s neck block into the neck’s tenon. The neck has been reset at least once, and the screw is probably a clue that the reset didn’t go that well.



The old top's color under finish compared to the new top's color under finish.
The new top needed to be toned down to match the old top’s color more closely. I guess I’ll have to drop a bag of hammers on the new top to simulate 75 years of being played hard and put away wet.

I’m currently finishing the top of this guitar, then I’ll need to reset the bridge and glue the neck in place. But, it shouldn’t be long until the guitar gets to try out her new voice. This guitar has been well-loved; it’s clear from the many repairs that have been done to it over the years to keep it going. I hope that the repairs I’m doing now will set her up for a long and happy second life.

3 thoughts on “Interesting Repair: Putting a new top on a 1940s D-18

    1. Hi Hugh, Ain’t that the truth. Bill’s guitar has had a full life, if life is measured by the challenges we face. 🙂 Hope you’re well!

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