Repair And Restoration
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76’ D-35 neck reset
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76’ D-35 neck reset
Hey looths,
Thoughts on process on this here guitar. I have a D-35 that has…
1) a drastic bow in the neck
2) quite a shallow neck angle
So diagnosis is, without an adjustable rod, I will need to compression fret this neck to get it back straight, and then proceed with a neck reset.
I’m wondering how fellow looths would approach this. Pull the neck and do the refret, then adjust the angle. Or do the reftret, and get the neck relief where we want it, then pull it and reset the angle.
I generally take a lot of measurements to approximate the neck reset, but that sort of approach needs to have a relatively straight neck. I honestly take the measurements more for my nerdy ways, rather than needing them, as most of the time, flossing gets me where I need to be.
Thoughts?
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11 Replies
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In these situations I pull the frets, level the board in a neck jig simulating string tension, install the new frets (minus the 15th), and then remove the neck. I like to have a straight neck for reference when flossing and projecting toward the bridge as it feels more predictable and accurate. After it’s installed I’ll dress the frets. The tiny little bit of fret height removed during that process doesn’t seem to affect the saddle height enough to be an issue.
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Chances are high that you have one of those old square rods in the neck. You can get a jump on the compression by gluing a carbon fiber reinforcement down the center of the square tube while clamping the neck straight.
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oooooo I like this idea. I’m sure I can find the carbon fiber rods easily enough. do you install them and then plug a square tube, or do you glue it into place with something like epoxy?
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I epoxy them in. You want the cf to be snug though. I think stewmac sells on that works well. Dan Erlewine does this too he might know. I’ll ask.
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I agree with Isn on the square tube fix: neck clamped straight (or in the position you want, if other than straight), carbon fiber rod or combo of rods to fill the the square hole with semi tight/loose fit and epoxy, sliding the carbon into the glue-filled hole like using a ramrod to load a musket until glue stops pumping out (with an apron around the exposed hole to catch squeeze out). You may even want to introduce a tad of backbow if you can judge/guess how weak the neck wood is, which can easily be wrong. Good luck, and thanks for sharing! Dan
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Here is an excerpt from a SM video on doing this job: see it here: https://www.stewmac.com/video-and-ideas/trade-secrets/strengthening-a-square-tube-martin-truss-rod/
The SMac 1/4″ x .200″ carbon fiber rod slides easily into the tube. There’s a little gap beside this rectangular rod in the square tube. Here I’m doing a test-fitting a strip of .020″ plastic binding, which creates a snug fit. (A thin strip of hardwood would also be a good choice of shim material.) Now that I know the pieces fit, I’ll pull them out and set up for gluing.
stewmac.com
Strengthening a square-tube Martin truss rod - StewMac
Dan Erlewine's doing a neck reset on a Martin that has a square-tube truss rod. While he has the neck off, he shows how to improve the truss rod before regluing the neck.
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Thanks @ianhatesguitars and @danerlewine for the tips. I’m ordering CF rods now and will definitely install them.
I’ve done 20-30 neck resets at this point and there’s still two points that give me gruff, maybe if you have input, somone else may find this post and learn….
First is breaking glue joints. I don’t seem to have much of a problem with bridges, but fretboard extensions always give me problems. I end up scooping up a chunk of spruce with the fretboard. I use the orange heat pads for bridges and extensions with a variac. I usually get the heat somewhere up near 175 F and leave it be for 10-15 min. Should I be using more heat for longer? This D-35 gave me a lot of gruff that I’d like to make smoother next time….
Second, to shim under the fretboard extension or not? The look of very dramatic fall away for some of the more intense angle adjustments is a bit unsightly. The biggest question I have is how you go about making them? I always struggle making these, either to sharp or shallow…any tips?
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For releasing FB extensions I go north of that in heat and north of that in time. 76 is probably white glue if unmolested and really responds well the pressure and heat. Some times I get it hot enough to slip the pallet knife under a 1/4 and then wedge it with a second pallet knife. I’ll mask that assortment off with aluminum foil and let it sit with heat for a while.
After that I might move the wedge knife in a little. Bottom line, it should go in easy on white glue. You shouldn’t hear any crunching or cracking from the spruce.
Sometimes with extreme runout going the wrong way, I might set up the guitar in the neck popper jig, heat the dovetail and the fb at the same time with pressure from the popper on the neck. If I get the FB to go “eeep!” from the opposite direction, I’ll work it that way.
Also, sometimes you are just hosed. Extreme run out can be impossible.
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FB extension shims. I always shim unless otherwise told not to by the client. If it’s going to be an extreme example, I might pass on the project as without context, it would make me look like a rookie by modern sensibilities.
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Thanks for the tips @ianhatesguitars .
How do you approach making your shims?
I may have asked before, but I generally try to use a piece of ebony on a belt sander with a holder of some kind and try to eyeball it…just looking for more predictable results . I could use my drum sander I suppose and try to kick up one side enough and just try to be mindful of drum pressure so it doesn’t shoot out
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Wow! I’ve done several of these, that carbon fiber trick is new to me. Definitely using it on the next one. Some of those 70’s necks are sooo spongy. I’ve had to use the thickest tang on every single fret on more than one. Even over the extension, and yes that helped and was confirmed by TJ’s talk at Northwoods on the Bar Frets.
Extension shim yes, if the drop off is .020″ or more. I just use a headplate veneer with 3 drops of thick CA glued to a sacrificial board and take it to the sander. Doug showed Danny West a cool trick with the same idea and 2 1/4″ dowels. Probably convert to that method.
I reset the neck first, sandout FB then fret last. My methods are too difficult to describe in text. All I can say it’s a lot of trial and error until you get the hang of it. Don’t be surprised if you have to pull many frets in the beginning before you start to figure it out…having said that I will start stringing the guitar up to “a tension” even before all the frets are installed to see where I’m at. This is before any fret ends are cut.
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