I've started my nylon string crossover guitar

[Lonnie B]

Very nice Kev.

[Herman]

Martial artist, you Kevin.
Herman

[Kevin in California]

Interesting. Swordmade Sjostrand guitars.

[Kevin in California]

I pulled the neck off last night because the heel at the end cap had pulled away from the body. This is a bolt on mortise/tenon, but I had glued down the fretboard. Man o man, I guess I used way too much glue as this fretboard was a bugger to get loose and I tore up some of the spruce. Also, I found that my threaded inserts in the tenon both had failed and were pulling out, even though I had weeped in CA around the threads. This is the second failure of this type of inserts which solidifies my decision to switch to the barrel nuts set in the tenon from now on.
So I did some patching of the top spruce last night, and I ran a lot of CA down around the inserts, hoping they will hold. I will glue the fretboard extension down again, and I'm considering putting a little glue on the heel cheeks to hold them in place in case those inserts fail again. I know all about how nice the M & T joint is for taking the neck off as I've done this a lot on previous builds to get the set angle and all just right. This guitar is for me and at least I'll know what I'm dealing with in the future if I have any neck issues. In my mind I can just treat it as if it was a spanish heel inleted sides construction like a classical guitar usually has. Anyway, I embarrassed myself at the trouble I had getting the fretboard extension loose.
I'll have some hand planing and sanding to do tonight on the top and see if I can get the neck fitting good again.

[Dave Bagwill]

Sorry to hear that, Kevin. Those inserts failing - on two different guitars? - makes me wonder about using the CA. I read somewhere recently that CA shear strength is not up to, say, epoxy, which makes it good for some applications but maybe not for this?
Anyway, I'm sure you'll fix this up and it will be a great guitar.

[ken cierp]

Have a picture of the insert? Fine threaded inserts are not suitable.

Over torquing the bolt is the thing that causes the insert to break loose from the adhesive. It does not take much to keep the neck seated -- just enough to compress the Bellville washer (you are using a compression washer right?) as a matter of fact there is a pro that teaches on the east coast, his method uses a single bolt and brass insert.

Also if the insert is put in backwards there really is not defined thread (very common since the shot on the course thread insert is a tap to cut the thread not a screw driver slot). And too an over size hole is a common problem.

[Kevin in California]

These inserts have never cut into the end grain of the mahogany cleanly which is why I flood CA around them, but I guess that didn't even work. I did find at one time I had them backwards, but these were put in correctly. I am using Bellevue washers, and I try to not over tighten, but sometimes I don't know my own strength.
I've seen some inserts with really coarse threads, and understand that they are not correct either. So maybe I don't have the correct ones. I'll post a pic of them tonight when I get home.