Official Luthiers Forum!

This afternoon a friend showed me the guitar she's owned for 46 years, and it was second-hand when it was purchased. It clearly needs a neck reset, but otherwise appears nicely made and sounds very good indeed. It's obviously a budget instrument, but so far as I can see it's a solid spruce soundboard, and solid mahogany back and sides. Not worth the cost of professional attention, but as an amateur builder I might attempt it for her to make it playable again. The saddle is a mere sliver, and was that way in 1974, so I suspect it is a decade or so older and was already in need of a reset when it was bought.

Unexpectedly, it's ladder rather than X-braced, so that might help identify it.

At one time it had a label - the top layer of the label is missing, so no help there, and there is no logo or any other clue. I'm hoping that maybe the combination of headstock back and front plus heel will ring a bell with someone. I'm pretty sure the screwed on pick guard is a later addition.

If anyone knows what make it is, next comes the $50,000 dollar question - what kind of neck joint? There are no bolts visibly on the neck block, so I think it must be dovetail or dowel. The construction is very nicely done - very neat joints, nicely shaped (and pretty light) braces, etc. which makes me think a dovetail is most likely.

My hunch, based on no real evidence other than the quality of construction, is that it is Japanese and from some time in the 1960s. There seem to have been quite a few Japanese makers of ladder-braced dreadnaughts. I found an image of a Kasuga 12 string which appears to have the same inlay on its 17th fret as this has for all the fretboard markers, but the headstock is dissimilar and all the other Kasuga images I find have a headstock logo.

Any thoughts?

Don't count on it being a dovetail. Could be. But it could also be a butt joint reinforced with dowels. Could also be a "mystery glue" neck join that is very difficult to remove without damage.

Looks like they went a long way towards trying to make this look like an old Gibson, like an LG or B Series. If that's the case the pickguard could be original. If they really took that much time to make good, tight joints and everything looks clean, could be an indication that they were trying to make it as much like the real thing as possible. I would try pulling the 15th fret and drill a hole. If it falls into a pocket, then it's probably dovetail. If not, you probably got a doweled butt joint.
If it's a dovetail, I would be worried about what Barry said. You don't really know what kind of glue it is. I wouldn't try steam with a mystery glue. You may be better off with the heat stick method. I don't have one yet, but if this guitar was in my shop it would be the perfect excuse for me to invest in one of those.

_________________
PMoMC

I usually try steaming off mystery joints unless it's somewhat obvious. If that fails cut it off and convert to bolt on.

Thanks all, I'll bear these points in mind.

Not surprised no-one recognised it, but it was worth asking.

After further thought I decided to remove the fingerboard back to the 12th fret to expose the joint. It is in fact a dovetail.

However, the fingerboard glue is odd stuff - it softens with heat but is still very, very sticky, and doesn't seem to dissolve with water. However, it's not any epoxy I've ever seen.

I've used a heat stick, inserted along the joint either side, and have some movement at the top of the dovetail and the tip of the heel. But in the middle of the joint, nothing. My guess is that it's the same glue, and as it seems to be a very closely fitting joint the glue is stopping the dovetail sliding upwards.

There was a heavy layer of finish over the joint where the heel meets the sides, and I've cut more deeply into that in case finish seeped in and was sticking the neck to the sides. I'll heat again and see if I can get it free.

If all that fails, my plan is to drill out the sides of the dovetail (I found John Arnold suggesting this on a thread elsewhere) to remove it. Then I have two options:

1. Clean up and rebuild the dovetail with thick shims, or

2. Turn the joint into a mortice and tenon and bolt the neck on.

Any views as to which of these is most likely to be successful for me, bearing in mind that I'm not an experienced repairer?

I'm not surprised dovetail joints were used on inexpensive instruments back in the day, not so much in the last 30 years.

A mortise and tenon joint is not your only option. I usually convert these to a butt joint.

I considered this, but if I leave enough of the dovetail to make the tenon then I can fit an insert so that the fasteners can go into side grain. If I cut the neck off at the body join, the truss rod gets in the way of adding the insert.

The heel laminations are threatening to separate, so I think my plan is to try to remove enough material from the dovetail sides to get the neck off. Then, if what is left will make a suitable tenon, go with that and bolts. If not, a simple bolt-on butt joint.

All good learning experience!

Old Japanese guitars usually had a date stamped on the neck block or on the sides. Not a calendar date, but a date based on the reign of the emperor. Look carefully inside with a mirror.
For example: https://yairiluvr.wordpress.com/2009/08/19/emperor-dating-code/
Will not give you a brand, but may be a year.

Since it's not a high value guitar, and it is a stacked heel, here's something to consider even if unconventional.

Take a thin kerf Japanese saw and cut through the heel along the stacked heel glue joint. I'm betting you could free up the neck shaft leaving the stiletto end of the heel in place. Tap a thin hardwood wedge into the sawcut to crack the dovetail portion.

A little clean-up of the joint with some careful chisel work and fitting to prepare a new glue surface. Do the same to the neck shaft incorporating the neck angle adjustment (reset) as necessary and glue the neck shaft back to the heel. Line everything up and glue the shaft back to the remaining heel section.

I've done that on purpose when making a heel of contrasting wood and it was not a problem and actually offered a lot of opportunity to refine neck geometry.

May have to glue in a shim to make up for the saw kerf but maybe not even that will be necessary. If you make the male dovetail part of the neck shaft fit the female part it should be as good as ever.

Saves a lot of potential to avoid damage IMO.

Touch up and good to go.

But I'm just a cabinet maker who builds stringed instruments, fiddles, banjos and guitars, so take it for what it's worth.

_________________
Brian R, Wood Mechanic
N8ZED

Brian, do you have any photos of that process?

Not really any process pics Barry but a finished one. It was my first guitar so I was trying to make the best use of wood I had and hesitant to use my best woods. So it was a scarfed head and stacked heel. I thought as long as the stacked heel was going to show, I thought why not make it worth looking at. It was an M&T joint and I had a block of ebony so...here's what happened. Back and side wood was EIR and the back on the wild grain side from wood I had in my stash for 50 yrs from my furniture days.

I fit the ebony portion to the body and bolted it in and then fit the neck shaft to the body and heel. Then took the heel off the body and glued it to the shaft after getting all the geometry right. The process gave me more time to fiddle with lining everything up. I kinda liked the look. Maybe the pic will help you visualize what I did.

I could have glued the shaft to the heel while attached to the body but in my case I didn't have to.

_________________
Brian R, Wood Mechanic
N8ZED