Bolt-on necks with glue?

ukegirl13

ukegirl13

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Hi everyone and happy holidays! I am getting ready to attach an uke neck with a bolt-on system (bolt with break-down furniture connector) for the first time and am wondering if I add in any glue/epoxy into the barrel before screwing the neck onto the body or do I just add glue to the back of the extended fretboard and just tighten the bolt down with the Allen wrench?

Any advice is greatly appreciated!
 
You should take care not to glue the threads of the machine screw to the internal threads of the barrel, though!
 
Once I have the neck aligned i drop a blob of medium viscocity suoperglue down the barrel hole - never had glue on the threads...
 
so, it is not exactly necessary to add glue in between the neck and the body (sides), is it?
thanks guys.:eek:
 
I'm going to be a little contrary. I put a few drops of Titebond into the hole to keep the nut from falling out. It's happened before that the nut has taken a walk unbeknowst to me after I've glued on the fret board. I wouldn't feel good about using ca for fear that it would work it's way into the threads. And I always put a tiny smear of the same glue on the end of the bolt when I attach the neck. I've retightened the bolts on a couple of personal ukes of mine where the bolts have loosened a bit after 20 years or so.
 
I made 4 banjo ukes this way about 9 years ago, I fitted the brass barrel in place with a dollop of epoxy, and held it there in position with a greased threaded bolt (the same thread size as the neck bolt), until the epoxy cured, then unscrewed the bolt... the grease acts as a releasing agent on the threads.
 
Re. the neck bolts or machine screws coming loose...I believe that is due to the use of solid mahogany internal neck blocks. The mahogany will swell a bit in humid weather, but the bolt, washer, and bolt head of course do not move. The wood compresses and then when the humidity goes down and the neck block shrinks a bit, suddenly the bolt is loose, and the thicker your neck block, the worse will be the problem.

We use 1/2" Baltic birch plywood for both neck and butt blocks. The stuff doesn't split when instruments are dropped, and it doesn't seem to expand and compress with humidity changes. I think it's an all-around better material for those parts than solid mahogany. It answers to what those parts need to do in the instrument much better than the traditional materials do.
 
Rick Turner said:
Re. the neck bolts or machine screws coming loose...I believe that is due to the use of solid mahogany internal neck blocks. The mahogany will swell a bit in humid weather, but the bolt, washer, and bolt head of course do not move. The wood compresses and then when the humidity goes down and the neck block shrinks a bit, suddenly the bolt is loose, and the thicker your neck block, the worse will be the problem.

We use 1/2" Baltic birch plywood for both neck and butt blocks. The stuff doesn't split when instruments are dropped, and it doesn't seem to expand and compress with humidity changes. I think it's an all-around better material for those parts than solid mahogany. It answers to what those parts need to do in the instrument much better than the traditional materials do.
Click to expand...

I am using solid Mahogany neck and tail blocks. At least that's what I have been using. So, I should put a drop of glue onto the threads? I will try the Baltic Birch blocks on my next uke. Thank you, Rick.
 
Moore Bettah Ukuleles said:
I'm going to be a little contrary. I put a few drops of Titebond into the hole to keep the nut from falling out. It's happened before that the nut has taken a walk unbeknowst to me after I've glued on the fret board. I wouldn't feel good about using ca for fear that it would work it's way into the threads. And I always put a tiny smear of the same glue on the end of the bolt when I attach the neck. I've retightened the bolts on a couple of personal ukes of mine where the bolts have loosened a bit after 20 years or so.
Click to expand...

So, you do add glue just to the end of the bolt? Where it hits wood on the inside of the neck? And not threads to threads? Thanks, Chuck.
 
I believe what Rick is saying about wood getting compressed over time is right. That argues for Not setting the bolt with glue if using solid wood blocks. You will need to be able to retighten the bolt in time. Maybe an ever so mall amount of locktight.
 
Rick Turner said:
...
The mahogany will swell a bit in humid weather, but the bolt, washer, and bolt head of course do not move. The wood compresses and then when the humidity goes down and the neck block shrinks a bit, suddenly the bolt is loose, and the thicker your neck block, the worse will be the problem.
...
Click to expand...

Rick, only because you tend to correct other people's terminology: Clearly the wood does not compress when the humidity is high. I guess what you mean is that it will expand slightly with the humidity, and then shrink back when the humidity goes back down.

Anyway, no flame - thanks for the valuable observation. I haven't actually seen it happen with our instruments, but I might consider moving away from solid mahogany blocks, since we use bolt-on necks all the time.

BTW, we do not set the bolt with glue - neither into the wood, nor the cross dowel. On the contrary, so far we have waxed the threads to ensure they don't get stuck with glue when we glue the dowel into the neck.
 
Last edited:
I've been using this same bolt on type neck connection with the same hardware since 1985. A little dab of Titebond on the ends of the threads helps to keep the bolt from backing out if the wood shrinks a great deal. You can easily break the thread bond if you use PVA if you need to. As has been discussed in the past here, this glue is somewhat soft and pliable. I would never lubricate the bolt. Pretyy self defeating.
 
The wood expands, but under the bolt head and washer it compresses as the wood cannot naturally expand held by the metal. When the wood goes back to a lower humidity, the entire block shrinks and the compression under the bolt head and washer is very evident. I've seen this mostly on bolt-on neck guitars with fairly thick neck blocks, but the mechanics of it will be the same for ukes, just on a smaller scale.

Note that that is not the only reason to use something like Baltic birch ply for neck and butt blocks, though. It's just better all around. The only down side might be that it's more difficult to hand plane or sand when prepping rims for top and back glue-ups, but we use a 24" potter's wheel with radius dishes and 40 grit sand paper for that job, so it's just not an issue. If you examine a number of the build methods and materials used in vintage instruments you'll see that some of the choices were to accommodate the then-state-of-the-art tooling. We have more choices now, even on a small shop level.
 
A little Loctite on the thread will stop it from undoing but won't harden so much that it's hard to remove the screw (on purpose).
 
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