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Is it necessary to use bolts for a mortise an tenon neck joint or can it be glued as it is ?

John

If it's a straight M/T not a dovetail, you need the bolts.

Pat

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formerly known around here as burbank
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http://www.patfosterguitars.com

Jon Simpson's neck jig video demonstration has no bolts, that is what prompted me to ask the question

Depends on the grain orientation in the head block. If your glue surfaces are face grain to face grain and you have a good joint, it should be as strong as solid wood. I wouldn't be comfortable gluing face grain in the tenon to end grain in the neck block mortise.

That said, why not the more conventional bolt or dovetail?

If you do a glued M/T, I suggest leaving space at the end of the tenon, like on a dovetail, for injecting steam into the joint to get it apart for a neck reset.

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http://www.chassonguitars.com

IMO, gluing a straight MT sorta kinda defeats the purpose...

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https://soundcloud.com/jeffreylsuits/he ... -runnin-13

A glued M&T might be fine if the joint is nice and tight. If you have to adjust the angle of the neck at all, that will result in a tenon that doesn't fit the mortise and then you have no choice. A dovetail can be fitted tight even after fiddling with the joint due to the self-tightening function of the joint. You do not have that feature with a M&T. Bolts are so easy, it is why the majority of necks are attached this way now.

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"Building guitars looks hard, but it's actually much harder than it looks." Tom Buck

The reason for the bolts are for ease of doing a reset. No steaming of the joint and risk of melting the finish from the steam. If you don't glue the tongue down and bolt it too then you can have the neck off and on in no time without worry of any other problems.

As for the video, You will put the inserts in last after the tenon is cut.

The stick to neck M&T joint in National's are glued together but the grain is the same direction so it will hold. But gluing a M&T on a guitar is just defeating the purpose of the joint.

If you have a single bolt as in a martin neck , you need to glue it. If you have 2 bolts you are ok. As you original question yes a bolt should be used. I never seen a dovetail joint fail unless it was damaged. I have seen bolted mortise and tenon joints fail

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John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

Under normal conditions? I know you're better off gluing in a vertical strip of maple to make the insert hold better. You can certainly damage the joint by over tightening it too as you know. I think their was some test done on it in a past AL not to long ago.

The heel block would have to be drilled before it is glued in place and the body closed , does this cause any lining up problems late on ?

John

I rout my mortise once the body is closed and bindings/purflings are installed. It seems much easier that way, and it is not hard to have everything aligned and centred. To drill the holes for the bolts I install the inserts first on the neck tenon and use sharpened 1/4" rods to mark the mortise. The opposite can be done (holes drilled first in the mortise) with marking the tenon with a 1/4" transfer punch (through the soundhole). I've never had a tenon fail, but I drill for a 1/2" walnut dowel in the tenon so the inserts can bite in something else than end grain. I also secure them with thin CA.

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Laurent Brondel
West Paris, Maine - USA
http://www.laurentbrondel.com/

Yes I agree after I looked at Robbie's video on YouTube - it explained the process for adding bolts very well. I now have a query on the type of router bit an guide which I have created another post

My jig is just 2 sheets of 3/4" plywood at 90º angle and a pocket for the mortise cut in the sheet going over the neck block. I clamp the guitar body with cam clamps and align it with a centreline, a stop for the router is clamped for the mortise depth. My mortise is .800" wide, and that's the maximum I can use for a relatively thin heel. I use a pattern bit with the bearing over and usually cut in 2 passes, 3 if the bit is less than razor sharp.

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Laurent Brondel
West Paris, Maine - USA
http://www.laurentbrondel.com/

Does anyone have a description and or photos of a bolted tongue (fretboard extension). This looks like something I' like to try? Does it affect the sound in any way?

Do you mean like Sylvan Wells produces ?

For a small fee you can gain access to his restricted area, I am sure the details are listed there

J

You might try a search and look at the Taylor set up but some/most require a pocket and added wood under the extension. Or you could also float it like on an adjustable neck. The top is dead in that area where the UTB is as it's built for strength and etc. Now there is some question and discussion about opening up the upper bout when using a canterliver or floating extension and buttresses and replacing the UTB with an 'A' type bracing. You want the extension to be solid or it can make a fretted no weak like a loose fret.

Todd,
Any speculation as to why double M&T need work sooner?
I finished my first two recently with the Bourgeois style joint. When I called the customer to come get it I found out he had been laid off, point being that it sat ignored in a closet for a month. When I went to dust it off for pickup, the action on both (I made a pair as it was my first attempt) was atrocious. Partly due to too much neck relief, easily fixed, and partly due to, well, I don't know and it bugs me.
Unfortunately, I didn't measure top deflection when I set it up at first, and I changed how I do the rims, namely radiusing them instead of leaving them flat, so I don't know why this occured. Many changes at the same time. The neck moves a lot under tension, coming forward almost 1/4" when tuned up with 12-53's., I've never seen the like. Fortunately, all I had to do was bring the neck angle back, easily accomplished with this joint. Catch-22?
Has anyone else using this joint experienced this?

This is how I am building my next one...
http://www.defaoiteguitars.com/page33.htm
Michael

I use a neck extension with the FB glued to it, and a mortice in the top, however I do not bolt the extension down, my necks are just bolted on with the two bolts. Look at this thread, Page 3, for a full photo description of my system. I have built more than 30 guitar with this method and never had a neck move. I have never seen the point of bolting a neck on, then gluing the FB down.

http://www.luthiercom.org/phpBB3/viewtopic.php?f=107&t=1889&st=0&sk=t&sd=a&start=50

Colin

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I don't believe in anything, I simply make use of a set of reasonable working hypotheses.

Michael, I've built one this way and am very happy with it. It's been my daily player for almost two years. Maybe you're already planning to do this but I recommend that you make the bottom bolt accessible from the outside of the heel rather than from inside the box. Makes it much more convenient to change the neck angle as the humidity changes.

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Steve Smith
"Music is what feelings sound like"

Steve,
Are you're top or pivot bolts that low? I use the Doolin setup where the top bolt and pivot setscrews are a bit higher, just below the truss rod . I was wondering if you find there is any shift in the intonation with the Top bolt/ss being a little lower?

Chris, I've got my top bolt/pivots as high as possible for exactly that reason. I haven't tried them lower so I don't know if there would be a significant effect or not.

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Steve Smith
"Music is what feelings sound like"

I've used the type of double tenon joint described by Sylvan and John Mayes on 35 guitars and it's been basically stable. I have seen the bolts on the Cumpiano type attachment system as well as the fretboard tenon bolts loosen if the instrument dries out and the wood shrinks a little. I've always recommended checking them for tightness a couple of times in the first year. I've always wondered if that was a problem with the makers that hide the bolt ends under a label or wood veneer. I bet a few of those loosen and that can affect the neck angle.
The other problem I saw on one guitar that was over-humidified was that the unsupported end of the fretboard warped a little and went slightly concave causing it to rise a little.
John Mayes if you are reading this what has been your experience with this joint?

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It's not what you don't know that hurts you, it's what you do know that's wrong.

Steve, I have researched the outside the neck adjusting method, also known as Staufler-Legnani adjustable neck system. I have a friend in Belgium that uses a Bass string ferrule
http://www.stewmac.com/shop/Hardware,_p ... yword=4595
with a stainless steel bolt. It would provide easier access for adjusting but the neck becomes loose when the strings are removed. The Egmond company of Sweden made this joint with an internal spring to stabilize the neck.
Hope we are not straying too far from the original post.
Michael

Mine is captured and hidden behind a strap button. If you don't want a strap button you can dress the opening with a Tele ferrule as per Mike Doolin.