Mortise And Tennon Neck Attachment

[wohzah]

At first for my build i was planning on using a regular glue in neck, but after reading Martin Koch's building electric guitars he describes a heel that must be cut into the wood inorder to provide a larger gluing area thus strenthening the neck. My resutling idea was to combine the idea behind a bolt neck and a set neck and have a neck glued into the wood with two cylindrical tenons placed into the wood from the back of the neck joint into the neck almost in place of the bolts. My idea was that this would keep most of the tone and sustain of a set neck while still making things as easy as a bolt neck. Comments?

[Hector]

could you make a little drawing? I`m a bit stupid, and can`t understand what`s in your mind.

sorry

Edited March 6, 2008 by Hector

[killemall8]

i dont think thats necessary. a regular long tennon will do just fine and have enough strength.

[orgmorg]

There are many many ways to make a neck joint more complicated, but it is highly unlikely that any of them offer any real noticable improvement over the most simple methods.

[Setch]

A mortice and tenon with dowels will be more complicated and less strong than a conventional one, and less strong than a conventional bolt on too.

The dowels will add nothing to the joint at all.

[wohzah]

So how does a glue in neck have the strength to stay in if it just a block of wood set tightly into the wood via a tight joint? Can glue really be that strong, there must be some kind of jointery or mortise. Simply a larger gluing area is really strong enough?

[Setch]

Glue is very weak, but the chemical bond created when a well fitted joint is glued together is extremely strong - to quote the old motto it is 'stronger than the wood itself'.

[mongrel666]

Glue is very weak, but the chemical bond created when a well fitted joint is glued together is extremely strong - to quote the old motto it is 'stronger than the wood itself'.

Yup, dead on.

forces in a guitar neck are mostly shear forces, so the long bottom and the long side glueing area are HUGE in comparison with the load. If the forces were otherwise oriented then bolt on necks would rip out. Early SG guitars had small tennons that on went to the neck pickup and because they were a double cut-away the neck tended to pop out - not enough glueing surface area. They then extended the tennon under the neck pickup and rectified the problem (if they can survive Angus Young...) The other thing to look at is the scarf joint at the head stock of accoustics and some electrics, very small area of glue, but a largeish shear area, still the same string tension...

[doug]

+1 - on not making it any more difficult than necessary...

Just make sure your neck pocket is snug. The resulting joint will be very strong. Be sure the neck heel goes in at least as deep as the back of the neck pickup cavity. Also, be sure there is a fair amount of heel left under the neck pocket. You just don't want that too thin. There's a ton of material on set neck construction available as well to help you out.

-Doug

[j. pierce]

Early SG guitars had small tennons that on went to the neck pickup and because they were a double cut-away the neck tended to pop out - not enough glueing surface area. They then extended the tennon under the neck pickup and rectified the problem (if they can survive Angus Young...) The other thing to look at is the scarf joint at the head stock of accoustics and some electrics, very small area of glue, but a largeish shear area, still the same string tension...

They really popped out? I've never seen that. I used to love the old small-pocket SGs because there was enough flex for "push on the neck" trem, and there was even pitch wobble if you spun around enough, but I never heard of one popping out. Makes me seriously reconsider my plans to build a copy of my old (long gone) SG…

[mongrel666]

Early SG guitars had small tennons that on went to the neck pickup and because they were a double cut-away the neck tended to pop out - not enough glueing surface area. They then extended the tennon under the neck pickup and rectified the problem (if they can survive Angus Young...) The other thing to look at is the scarf joint at the head stock of accoustics and some electrics, very small area of glue, but a largeish shear area, still the same string tension...

They really popped out? I've never seen that. I used to love the old small-pocket SGs because there was enough flex for "push on the neck" trem, and there was even pitch wobble if you spun around enough, but I never heard of one popping out. Makes me seriously reconsider my plans to build a copy of my old (long gone) SG…

Yeah, apparently, though it was considered a design flaw rather than a full on epidemic. I dont mean that you would get one out of the box and every one would do it but there were enough problems for them to initiate a redesign. I guess the thin body would have conributed to the problem, plus the double cut-away. Production methods and the like would also have made each instrument vary considerably, imagine such a small tenon with a sloppy mortice. Uuggghhh!

I would hope that any "flex" you got by pushing on a neck was the neck itself bending rather than the tenon moving or flexing. I can flex the neck on my strat and get a bit of a wobble, but the trem could be taking up the slack of the strings as well, dunno.

[Desopolis]

when I route out a neck pocket, i make it so the joint alone can hold the body without glue:

it should rely on that bond just as much as the glue