Dovetail Joint

[B. Howard]

The tenon should always be a snug fit. When re-setting a neck, M&T or dovetail, you should only work the cheeks to adjust set angle. Assuming the neck was set proper in the first place there will be no need to adjust for center. FWIW I set my dovetails on my new guitars by working only the cheeks. Best way to screw up the fit of a well machined dovetail is to start messing with the mating angles.

Each surface of the joint has a job to do, this is a little different in on guitars then in general woodworking because our M&T joint is open on one side. Making it behave more like a double bridle joint in some ways. The sides of the tenon against the sides of the mortise are what keeps the neck on center. If these are fit too lose the neck can and most likely will shift during seasonal movements and string changes. The cheeks bearing against the rims is what sets the angle. The "bottom" of the joint will likely have some clearance as the FB extension will take over it's traditional job of setting the "depth" or height of the neck. The bolts merely take the place of a glue and keep it from falling off. It does not matter if the bolts fit through the holes tight or loose as long as they allow the neck to seat properly, in fact it's better if they are a little loose so there is no chance of them binding before the neck seats all the way.

[Zen]

If the angle is right and it is centered sounds to me like you have a good joint. It should only take a tap to unseat an unglued dove tail.

I would wait for John for a real answer as I already switched to bolt on mortise and tenon.

Why did you switch --just curious as I made a promise to myself some while back that I would never again use a dovetail joint on a guitar. With hind sight I can put it down to inexperience now,but back then I almost had a nervous breakdown trying to solve the neck angle problem etc etc etc. Thankfully, with the help of you guys on the forum here I plodded through and its now one of the best sounding instruments I ever played. Having said that, i think that neck joint will haunt me forever lol

[tippie53]

As Brian points out , the neck needs to be secure. It took me about 10 guitars to get the dovetail perfected. I can do one in about 5 to 10 minutes now but it took a while to master it.

[Darryl Young]

John, will you be hosting a get-together at you house again this year?

[johnnparchem]

If the angle is right and it is centered sounds to me like you have a good joint. It should only take a tap to unseat an unglued dove tail.

I would wait for John for a real answer as I already switched to bolt on mortise and tenon.

Why did you switch --just curious as I made a promise to myself some while back that I would never again use a dovetail joint on a guitar. With hind sight I can put it down to inexperience now,but back then I almost had a nervous breakdown trying to solve the neck angle problem etc etc etc. Thankfully, with the help of you guys on the forum here I plodded through and its now one of the best sounding instruments I ever played. Having said that, i think that neck joint will haunt me forever lol

I am glad you worked through it and ended up with a guitar you like. I switched because it was a lot easier to cut the tenon and route the mortise. I suppose with the correct bits and templates it would be the same.

In terms of setting the neck I found that the hard part for both, cutting the correct angle on each cheek, and keeping the cheeks square for a clean line on the rims, is the same. Maybe a little easier on the mortise and tenon as you can start out with a fully seated neck. Once I moved away from sand paper to chisels I found setting the actual joint not too hard. I use chalk to note the high areas on the tenon and only chisel off the marked areas after attempting to seat the neck. Very quickly the entire tenon is being marked and I just take thin shaving off of each side again just attempting to remove the chalk. I repeat until the neck is seated as deep as it is suppose to be.

[tippie53]

This year is ASIA symposium in East Stroudsburg. Hope to see you guys there

[naccoachbob]

John, or anyone who'd like to help, here's where I am now that the guitar has finish on it.
My neck angle is good, my centerline is good.
My fretboard is about 3/64" above the surface of the top.
I am lowering the neck gently, but here's what I see when I chalk it.
On the bass side, I see chalk about the middle of the tenon, but on the treble side, I see chalk over almost the entire side of it. It's a dovetail, so tenon might be the wrong word, but I'm talking about the male portion of the dovetail.
When I hammer the neck into place, it feels strong. I don't feel any wiggle from either side to side or top to back.
Just wondering if I need to concentrate on that part of the treble side that seems to be gripping. Should I sand it down so that more of the side of it has chalk, and therefore grip?
Thanks,
Bob

[tippie53]

keep it simple
yes it is tenon , and when you think about the mechanics of this joint , it is to get tighter as it goes into the mortise . That tells you that the working part of the joints is the lower end of the tenon so as it gets forced into the block , it pulls the neck into the block.
You want to see chalk on the lower part of the tenon , if the entire tenon is covered so be it , as long as that lower part has chalk you are good.