How would you fix a headstock problem like this?

[belbein]

I know nothing about this mando. I've asked on another post if anyone recognizes it.

The question is: How would you fix this?



I'm assuming this is a beater, perhaps home made, since there is no label, no trade mark, and the top is a (now disintegrating) laminate. All of that says to me: DON'T replace the neck.

I have a few ideas, but ...

[billhay4]

A good glue and dowel job would do it.
Bill

[sunburst]

If that's a new break (fresh wood surfaces, not old and oxidized) and it will align nearly perfectly when clamped, a dose of hot hide glue and clamping overnight is all it needs. If it is an older break, and alignment is good; same thing with slightly less confidence. If it is an old break and the alignment is not good... what is the value of the instrument and how much time can you afford to put into it?

[MikeEdgerton]

I've always glued them and clamped them. Sometimes you need to create a caul so you can get it clamped evenly.

Here's an article from Frank Ford's www.frets.com.

[Rob Grant]

"...and the top is a (now disintegrating) laminate."

Sounds like good material to use to get that old wood stove going on a cold morning.<g>

[belbein]

As for what it's worth ... I really don't know. Before I throw it in the stove--Rob, we're about five months from anything that I would call a "cold morning" around here--I figured I'd teach myself a few tricks.

I suspect it's not worth much. I mean, a plywood top? The finish is nearly completely gone, and that confirms the only bit of history I know, that it's at least 50 years old. So, anyway, it's probably worth less than $1 mil, and it's a good guinea pig.

I'm willing to spend a lot of time, figuring that whatever I learn will come in handy when a drunk steps on my mandolin or my wife backs over it. So, Sunburst, hit me with your best fix (other than re-making the neck, which I'm NOT going to do).

Billyhay4: On the dowel thing ... would that dowel run vertically through the crack--i.e., more or less at a 90 degree angle to the fracture? Or would it run through the crack, parallel to the long sides of the headstock, and down to the intact wood?

[Folkmusician.com]

I don't do a whole lot of repairs, but shipping the volume of mandolins we do, headstock whiplash is one that I have become overly familiar with. As John recommends, hot hide glue will take care of a fresh clean break and you shouldn't have any future problems. Based on your description, and the things vaguely resembling tuner buttons, it sounds like this one might not want to be revived.

[MikeEdgerton]

Before you dowel anything go over to www.frets.com, go to the index page, select Items of interest to Luthiers and scroll down to the headstock repair section. Read them all, it will only take you a few minutes. Putting a dowel in that thing probably won't make it stronger.

[Bill Snyder]

You notice the two pros that have chimed in suggested HHG and clamping and said nothing of dowels.

[sunburst]

I'll mention dowels, and my advise about them; don't.
Dowels are for alignment, not strength in most situations. Drilling for them takes away gluing surface and therefore usually weakens the joint. If the split surfaces fit back together well (alignment is good), the work of alignment dowels is not needed.

OK, so, hit you with my best fix? The more-oe-less rhetorical question about value and how much time it is worth was asked because the repair is different depending upon the value. If I was fixing it for a student or player and it has little or no value and alignment of the split was poor, I'd just epoxy it and send it back into service for as little of the customers money and my time as possible. If it was a valuable instrument and needed to look good following the repair and alignment of the split was poor, I might resurface both split surfaces and sandwich in a piece of matching wood (with HHG), blend the contours and touch up the finish. If you are using it as a learning tool, I'd suggest checking the alignment and if it is good at all, try gluing it with hide glue and see how invisible you can make it without disturbing any more wood and finish than necessary. That's a good skill to develop. If the alignment is very poor, feel free to try the sandwich thing, but be prepared for plenty of head scratching and devising ways to keep everything lined up while clamping and drying.

[Ben Milne]

I'm no pro, but if I were to go further than gluing and clamping, for structural integrity I would probably consider a veneer or two before thinking about dowels. Perhaps a combination rear veneer/volute that extends along the headstock, thicker materierial between the tuner plates, maybe

[belbein]

Thanks for the responses. I am going to use this as a learning tool, since the mandolin itself is basically not worth anything. Though if I can get it up and running, it would be kind'a cool.

I can easily do the HHG or epoxy, since the alignment is excellent and the fracture is very clean. However, I'm very curious about how the sandwhich thing works. Would I glue together the fracture, then laminate a thin piece of laminate on the top and the bottom faces of the headstock? Or am I doing more major surgery ... like cut a slice out of the middle of the headstock, parallel to the faces, then glue those?

(John, thanks for the advice about learning ... I really appreciate the hint on skills. I am trying to develop my skills, little by little, since I keep ending up with more (broken) mandolins in my workshop. It helps to know what i need to know.)

[Marc Berman]

Here's a good frets.com article with a repair similar to yours.

[MikeEdgerton]

I guess I'm a little confused at your aversion to simply using glue and a clamp to fix this. If you have a clean aligned break and you fix it you'll learn more from that simple act than any amount of messing with it will ever teach you.

[testore]

I've seen a million dowels and they always fail. What is REALLY the problem is that they ALWAYS make the next repair almost impossible. I HATE DOWELS!!

[sunburst]

I'm very curious about how the sandwhich thing works.

First of all, you say the alignment is good, so you don't need to do this(!), but it would involve shaving away wood on each split surface so that you have flat, smooth gluing surfaces, then gluing a piece of wood between the two surfaces to replace the wood that was removed surfacing the split faces. Careful measurements of dimensions and angle must be taken and maintained throughout the process, it's not a quick and easy fix, but I wouldn't call it "major surgery", and it certainly isn't warranted in this case.

[Paul Hostetter]

Another voice in the choir, singing "No dowels!"

[billhay4]

I stand corrected, but it seems to me that some sort of cross grain reinforcement needs to be made here. The wood split along the grain line and the strings are pulling in exactly that direction. Sure, glue is considered stronger than wood in many cases, but I'd still not like to depend solely on glue to hold this together.
More corrections welcome.
Bill

[Marty Jacobson]

I stand corrected, but it seems to me that some sort of cross grain reinforcement needs to be made here. The wood split along the grain line and the strings are pulling in exactly that direction. Sure, glue is considered stronger than wood in many cases, but I'd still not like to depend solely on glue to hold this together.
More corrections welcome.
Bill

I think the rationale is that this is very similar to a scarf joint. There is a lot of surface area, especially since the rise and fall of the grain along the neck axis adds to the amount of surface area on the mating surfaces. Necks have been made with scarf joints in them for a long time (though mostly in classical guitar construction, right?).. so presumably this will be OK.

I know a "slice" of cross-grain reinforcement is often added when repairing violin bows, I could see something like that being helpful, but with all that surface area, is it necessary?

[Paul Hostetter]

I stand corrected, but it seems to me that some sort of cross grain reinforcement needs to be made here. The wood split along the grain line and the strings are pulling in exactly that direction. Sure, glue is considered stronger than wood in many cases, but I'd still not like to depend solely on glue to hold this together.

Every dowel (or added anything) results in more loss of contact between the two surfaces, compromising the simple glue joint.

[the padma]

You gotta make sure the dowels run parallel to the break on each side of it....They won't do any good this way but then they ain't worth doin across the grains break ether.

Glue, culls and clamps. Simple.


blessings
duh Padma

[Paul Hostetter]

Huh?

[billhay4]

Every dowel (or added anything) results in more loss of contact between the two surfaces, compromising the simple glue joint.

I don't quite buy this. It does reduce the surface are that is to be glued by the area of the spline, dowel, whatever. But it adds two things: other surface area that is glued (the spline, dowel, etc.) AND wood grain running in a different direction to the split or break.
Since the original break followed a weakness in the wood (relative to the stresses on it), I would think this would be a strengthening element.
That being said, a spline, dowel, etc. does make future repairs almost impossible. In addition, they must be done very precisely or they themselves will develop structural problems under stress. This may outweigh their advantage, but there are certainly advantages to be considered.
IMHO.
Bill

[sunburst]

Dowels and splines are different things. I use splines occasionally on peghead re-glues when there is cross-grain fracturing of the wood, but not dowels. End grain does not glue well, but side grain does. When a split (like this one) fits together well there is plenty of side grain wood to glue, so a good glue joint can be had. A hole for a dowel presents less than 50% side grain to the glue joint (unless the hole is drilled into end grain), and some end grain, and it is usually a drilled hole. I don't know of any drill bits that cut a surface that I would consider acceptable as a high quality gluing surface even in the side grain portion of the hole. Add to that the fact that the dowel must be smaller than the hole to fit into it, or be forced into the hole risking splitting and compressing the wood of the gluing surfaces, and there is no particularly good way to get a really good glue joint holding a dowel in a hole.

Splines present side grain to side grain, and if fit well, can strengthen a cross grain fractured situation, but they would add no strength in this situation, and would probably detract from strength because, like dowels, the excavation for them removes some of the gluing surface at the split.

As for the break following a weakness in the wood, whatever broke that peghead was a force strong enough to break it somewhere. Wood strength is limited and enough force will break it, especially where there is severe grain run out as in a peghead with this type of neck construction. The break does not necessarily indicate a specific weakness, only the area of the structure where whatever force broke it accumulated enough to cause failure.

Anyway, I hope that helps explain why some of us frown on dowels for reasons other than the problems they present to future repair attempts.

[Paul Hostetter]

Well said, John.