DIY neck reset

[Perry Babasin]

I found a posting on a forum and mixed a paste of vinegar and cornstarch until it was thick enough to paint on vertical surfaces. Similar to De-Glue-Goo but cheap and typically at hand. It works great on white glue, even old hard, ancient crusty white glue.

[multidon]

Mind you, I have done some repairs and restorations in the past, but am only an armchair luthier these days. So do take this with a grain of salt. But in my opinion the best way to repair this would be to bolt (screw) through the inside into the neck heel. The same way Breedlove and Weber necks are attached. You could take out the end pin and buy a really long drill bit that will reach the neck block and drill your pilot hole. Apply your glue then use a long enough screwdriver to drive a long enough screw through the inside of the neck block right into the bottom of the neck heel. The screw will act as an effective glue clamp and after the glue dries would act as a reinforcement. I would be surprised if a repair like this failed.

It looks like the strap button "repair" was incorrectly executed. There is a piece of hardware known as a "Billy bolt" that some use. The hole is drilled through the neck heel at an angle all the way through the neck block to the inside. The bolt holds the strap button but is not a screw at all, a long bolt that goes through to the other side and is held with a washer and nut. This is my opinion is a sloppy repair.

LMI sells neck heel threaded inserts used for mounting ukulele necks. Take a look at those. It would be a neat invisible repair that I think could be adapted to your situation.

http://www.lmii.com/products/mostly-...n-neck-inserts

[Steve Ostrander]

Another question: what is best glue to join the original bone nut to the FB? I have heard everything from Elmers to Titebond to CA to HHG. I have also heard that Elmers and TB should not be used. After soaking and scraping the Elmers the PO used on the neck/body joint, I'm inclined to avoid them. So that leaves CA or HHG?

I have also heard that no glue is needed as the string tension will hold it in place. This would have sounded odd to me except when I removed the strings, the nut fell out and I see no evidence of glue on the neck.

[pointpergame]

In my experience, nuts have come both ways. I'm of the opinion that the nut should seat firmly across its width For the best sound conduction. I like hide glue for this reason, applied in precisely the correct quantity followed by three gently tightened strings to clamp the nut in place. The nut usually comes off easily with a thoughtful sideways tap from a properly shaped "drift pin." If absolutely necessary, some future luthier can re-flatten or remove the residual hide glue without a lot of trauma to upper neck of the instrument.

[sunburst]

I glue bone nuts to the end of the fingerboard with Titebond, usually, though sometimes a tiny drop of superglue. Either way, I want just a drop or two of glue so that the nut can be easily removed later. I don't put glue under the bottom of the nut, I don't want it glued to the neck wood that the nut sits on. If it is, removing the nut will usually pull some splinters of wood from the neck, and after a few times of doing that, the area must be resurfaced and neck wood is lost in the process. I like for the nut to fit well against the end of the fingerboard and to fit well to the surface that it sits on. If the nut is in a slot (as opposed to some situations where a thin veneer is used on the peghead surface, or there is no peghead overlay at all) I like for the nut to fit just well enough that it is not sloppy feeling (not too tight) in the slot, and in all cases, just lightly glued to the end of the fingerboard only to keep it in place. When it's done this way, a light tap will remove the nut with no damage to the neck and no wood pulled from the neck surface under the nut.

Edit:
Additional information.
Titebond and Elmers are the same basic thing in a situation like this, and either will do the same job of holding the nut. They are PVA adhesives.
PVA will scrape right off of a bone nut, and it will scrape pretty cleanly off of the end of a fingerboard too. When the nut is glued to the end of the 'board (where the nut needs to be, when we think about it, the correct measured distance from the first fret, not siting back in a bed of glue with a gap to the 'board, as I've seen them) with PVA, and we tap it loose and remove it, it is a simple and quick procedure to scrape the glue off of the nut and off of the end of the 'board. It's not like removing a bunch of glue from a dovetail or other joint. Only a tiny bit of glue needs to be used, and only a little should be used because, as you mentioned, the nut will stay in place with only the strings holding it in place.
I regularly get instruments in the shop with nuts glued in as though someone thought some incredible force needs to be resisted to keep the nut in place. Sometimes I have to destroy the nut to remove it without risking damage to the instrument. Why do people think the nut needs to be glued so securely? Do they not realize it will have to be removed? Many instruments have been damaged by the removal of nuts that were glued over-zealously.

[pointpergame]

Well said, John. The experience of you folks who have seen multiple scores of instruments is invaluable for the rest of us.

[rockies]

I did a neck reset on a well used and loved Stradolin about 8 years ago and it is still being played heavily. This is an unbelievably great sounding mandolin. I coveted it while it was in my shop and I play a Heiden. The joint had come very loose and I removed it, cleaned out cavity down to bare wood. Then did the neck and glued maple shims to the sides of the neck. Put it in a jig I made with a exact height bridge in proper place to give the proper neck angle, used a laser level above my bench to align the neck and then chalk fitted the joint. Once fitted it was glued in the jig with LMii luthiers glue. I do have a series of photos of the repair if you want to contact me for them.
Dave

[Steve Ostrander]

I would prefer to use the screw through the neck block method, but there is no end pin hole, so I would have to drill one, which isn't the worst thing, I guess. I will give some thought to drilling an end pin hole, installing a neck block screw, and finishing with an end pin when the neck reset is complete. I thought about removing the back to install a neck block screw but from everything I've read here, probably is not a good idea for a DIY job by a first timer like myself.

Again, I REALLY appreciate all the advice.

[Steve Ostrander]

As Det. Colombo would say, "Just one more question".... I now have the neck reset complete and the Strad is strung up. It doesn't sound half bad, but the tuners are really stiff. I put a drop of light machine oil on them before stringing, but they are still very stiff. Like I can't turn them with my fingers stiff. Any suggestions? I don't know what brand of tuners they are, but they are original.

Other than that, I'm very happy with my first neck reset. I surely couldn't have done it without all the great advice I got here on the Café.

[multidon]

It could be that your strings are binding in the nut slots. Are they just as hard to turn without a string on them? If you really think it is the machines, they may need cleaning. Naphtha works well, cuts the crud and won't hurt anything. It would be even more effective if you could disassemble them and let them soak a while in the naphtha. Then scrub with an old toothbrush and reassemble. The best lubricant is actually Tri Flo, which is graphite in a liquid carrier which evaporates and leaves only the dry graphite behind. If this procedure doesn't work then replacement is probably the best option.

[pointpergame]

If they aren't bent or otherwise traumatized, spinning them with a string winder after cleaning them up sometimes does the trick.

[Bill Snyder]

H E R E is more detailed instructions on what multidon was suggesting.

[Steve Ostrander]

They worked pretty good before I strung it up, so it must be friction from the tuner posts against the hole in the headstock. There are no bushing in the holes. Will a dry lubricant damage the wood when it gets in the holes?

I should probably just replace them, but I'm trying to keep the Strad as original as I can.

[sunburst]

...There are no bushing in the holes...

Probably a misalignment problem, then.
Tuner posts have two bearings; 1-the tuner plate, 2-the peghead bushing or the wood of the hole itself. If the hole has no metal bushing, the wood can compress and wear under the pressure of the post under string tension. When that happens, the post gets pulled diagonally in the hole in the tuner plate. The gear on the post fits and tightens against a shoulder, and there is a designed clearance between it and another shoulder, and that space accommodates the thickness of the tuner plate. It doesn't take a lot of diagonal misalignment for that space to be insufficient and for binding to happen when turning the tuner.
To shorten that explanation and get to the point; when the post gets pulled diagonally out of alignment the gear binds on the tuner plate.
What to do about it? Some people loosen the screw that holds the gear to increase the clearance for the tuner plate, and that kind of works, but it leaves the screw holding the gear loose, and it can change position or loosen the rest of the way and fall out. It is not easy to add a shim (in the form of a tiny, thin washer under the gear) to increase the clearance, but if that is done, the screw can at least be tightened so that it stays put.
You could drill out the peghead holes and add bushings (being sure that alignment and spacing are good).
You could build up the part of the peghead holes where the tuner posts rest to improve alignment. That could be done by gluing in dowels of very hard wood (like ebony) and re-drilling the holes in good alignment.
Maybe there are other ways to correct the problem, but if alignment is the problem, simply replacing the tuners does nothing to correct that.

[kkmm]

Do it from the outside through a strap button.

One of my mandolin has oval sound hole and need a bolt there, so I did it from the inside instead. Look better this way.

[Steve Ostrander]

It seems like the easiest way to fix would be to add bushings. I assume these are available from Stew-Mac. Just need to figure out the correct size.

[murrmac]

I know the OP has completed his project, but just FTR, depending on your confidence in your chisel skills, it would have been doable to convert that straight mortise/tenon to a tapered dovetail joint.

There is enough wood there to undercut the sides of the mortise going from nothing at the front to, say, 1/8" at the back. Then glue in a 1/4" - 1/2" thick "eke" (it's not really a "shim") on either side of the mortise. The thickness is not critical, you just need to have enough wood to cut out your tapered dovetail recess. This is so that the strain is taken by a physical wedge shaped joint, and not purely dependent on glue strength.

Cut a tapered dovetail on the neck tenon, and then cut the recess to match. It would require careful measurement, as all one-off dovetails do, but it would provide the strongest possible repair, and would be neat and invisible into the bargain. For the neophyte, it also has the advantage that if you take too much off the sides of the mortise, you can just glue thin shims on the cheeks of the dovetail tenon and try again. Obviously the shoulders of the tenon, and the corresponding mating surfaces on the mortise, would have to be set slightly further in than the existing joint line, to make the repair invisible.

This would also have the advantage that you could do a dry fit, string up to tension, and test to see if your neck angle is correct. If adjustment is required, then you just trim however much is required off the shoulders of the heel, and shim the cheeks of the tenon accordingly.

Some previous experience of resetting Martin guitar necks would obviously be advantageous.

Just a note that I am using the traditional term "cheeks" to refer to the tapered sides of the tenon and the "shoulders" are the parts that terminate at the end of the neck and butt up to the mouth of the recess. Sometimes there is confusion with these terms ...