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Well I pulled one off that could be an entry for the doofus of the month club.

I used my Simpson jig to route my neck tenon yesterday and ended up routing the tenon so it angled off of the centerline. It is not only off the centerline, it is angled.

I think I might be able to save this neck by removing the rest of the tenon and just using a butt joint with inserts. I have not routed the mortise in the body yet, so this might be a workable option. My main concern is that from the neck joint to the back of the heal, I only have just over an inch of material. Is this enough to use an insert for this type of joint? The LMI inserts are ½” deep. I’m thinking that this could still work.

I hadn’t thought of using this type of joint before so I don’t have a lot of information on the proper way of doing it. What tolerances to I need to think of? Are there any best practices out there? I’ll spend some time with the search feature today before I make a move.

Thanks,

John

Tacoma guitars used butted bolt ons with similar inserts. They're heels were 7/8". I've recommend drilling a hole through the heel, and inserting a hardwood dowel. (as Tacoma and many others do) . For bolt ons I use hanger bolts instead of inserts. They take even less space. I use a hardwood dowel through the heel, but I also use a tenon. Here's a link to the hanger bolts I use. http://www.woodcraft.com/Product/2001694/3143/1420-Thread-112-Length-Hanger-Bolt.aspx

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I didn't mean to say it, but I meant what I said.
http://www.brackettinstruments.com/

John, you could build the tenon back up by gluing a thickness of wood to the side that is angled in, and re-cut the tenon.

Edit; I always insert a dowel from front to back at the intersection of the tenon and neck heel, so as to have cross grain for the hanger bolts or inserts.

Chuck

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Woody, which length of hanger bolt do you use ? I am guessing 2 1/2" , but am hoping 2", cuz that's the only size we can get over here in small quantities, unless somebody knows different. ...

Woody ,how are you using theses hanger bolts without an insert? Isn`t one end a machine thread that goes into an insert? I `m looking for a solution to bolt on a neck for a ukulele.
James

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James W Bolan
Nashville Tennessee

Not speaking for Woody,,,, I drill a 3/16" hole into the tenon and heel 1" deep and screw in the wood threaded side of the 1/4" diameter hanger bolt to a depth of 1". The machine thread side is left protruding so as to be attached with a nut in a recessed hole of the neck block. The length of the hanger bolt is determined by the depth of the neck block and the depth you recess the hole for the nut. I use a 2" hanger bolt.
The nut is recessed so it can be covered by a plug or sticker.

Chuck

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a stainless steel dome nut would look quite attractive ...

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What Chuck said, except I use a shorter hanger bolt.

Added/Edit, due to actually reading the previous posts. The hanger bolts I use are 1 1/2" total length. I just screw them into the neck until they "look right". I'll measure to see how far I actually screw them in.

Yep, a decorative nut would look nice, but I just counter sink the hole and cover them with a label.

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I didn't mean to say it, but I meant what I said.
http://www.brackettinstruments.com/

Whatever hardware you decide to use to hold the neck to the body, a butt join is a really good and strong neck to body join.

You can easily cut hanger bolts to length. I use a cut-off wheel in a Dremel. In order to maximize the thread in the wood, and eliminate the chance that over-tightening the bolt will screw it all the way through the heel, I use a hanger bolt with the point cut off so it has full-sized threads to its end. I first start the thread into the wood with a complete hanger bolt, which has a point on the end. Then I back it out and screw in a hanger bolt with the point cut off so the end is square. Perhaps unnecessarily, I put a little bit of epoxy in the hole before I screw the bolt in: it fills the little void left by the end of the drill bit, and maybe strengthens the threads of the wood.

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Tim Allen
"Never hurry, never rest."

good tips,but I`m not sure if I can reach thru the 2" diameter of the uke soundhole far enough to get a nut on a bolt.
James

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James W Bolan
Nashville Tennessee

That makes total sense, Tim.

There is one aspect of butt jointing which slightly disturbs me, and that is that if you don't have a tenon to register the neck/body joint, then OK you have the fretboard to act as a register point , but what about the sideways location ?

In nautical terms, you have the pitch sorted, but what about the yaw ?

Obviously, when using hanger bolts (or threaded inserts for that matter) , you have to allow a certain amount of tolerance in the holes in the neckblock, to allow for future resets.

Omitting the tenon, and just eyeballing the neck in place and gluing the fretboard down just seems a tad ...yeeeuggh ...

Yaw is determined by the butt face. Er...
If you sand material off the treble side, it will drive the stringline towards the bass side of centerline, opposite if you remove material from the bass side.
Unless you mean that you are concerned about the neck shifting side to side in the bolt holes. I've just done a run of butt joints. I used knockdown or furniture bolts, same as for use with the barrel nuts. They have a slight flare or flange where the threads join the hex head, and are therefore self-centering in the holes. I really like this joint, neck fit is now a fifteen minute operation at most...
I left my heel at 13/16. 1/2"insert, inset 1/16 into the heel.

You can. It is more difficult, but you can with the right size ratchet and extension. Getting the nut started is the hardest part.

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Kevin Mason
Mason Guitars and Ukuleles on Facebook
http://masonguitars.net

Sorry, yes, that was exactly what I meant, and I appreciate that "yaw" was the incorrect term, and that "yaw" would indeed determined by adjustment of the mating surfaces of the heel.

I use shrink tubing on the bolts to make a snug fit side to side in the holes.

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Ken Franklin
clumsy yet persistent
https://www.kenfranklinukulele.com

Great tip, Ken.

So, would the consensus of opinion among the experienced builders here be that accurate location of the holes in the neck block, and correspondingly accurate location of the holes for the hanger bolts in the heel is sufficient for accurate registration, and that a mortise and tenon is over-engineering the issue?

Re "So, would the consensus of opinion among the experienced builders here be that accurate location of the holes in the neck block, and correspondingly accurate location of the holes for the hanger bolts in the heel is sufficient for accurate registration, and that a mortise and tenon is over-engineering the issue?"

In my observation, there is a consensus about among experience builders about a few things, but not about using hanger bolts for neck joints. It seems to me that a majority of experienced builders believe you should use a tenon and extra hardware, such as threaded inserts or captured nuts. A substantial minority use hanger bolts.

I am neither an experienced builder nor an engineer; I am using hanger bolts based on the recommendation of someone who is. I am not personally advising others to do what I do, just telling what I do. I did check out information on the holding strength of screws in wood, which seemed to confirm hanger bolts would work. I have a dining table dated from 1940 that uses hanger bolts in oak; still sound. I have a Steinway "M" from 1926 that uses a lot of wood screws into mahogany; still holding. None of these things establish that hanger bolts in guitar neck joints are the right way to go, but they give me some confidence.

In terms of using the location of the holes in the neck block for registration, that's not how I do it. It seems to me that you need some clearance there, though too much slop would needlessly weaken the neck block. If holes guided the neck fit, but the heel and fretboard weren't aligned, it seems to me you'd have big gaps. In my limited experience, the heel block is shaped by "flossing" and the top of the guitar sanded to fit the fretboard, in such a way that the neck aligns. Seems to work, and not that difficult. YMMV so take this with a grain of salt.

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Tim Allen
"Never hurry, never rest."

Re-reading my post, I apologize for my badly worded question, I wasn't meaning to ask about hanger bolts v. other bolt-on methods (such as threaded inserts or threaded dowels, which I know many builders use).

What I was trying to ask was whether , among builders who use hanger bolts (or, for that matter, who use threaded inserts ) it is established practice to leave a short tenon on the end of the neck (it wouldn't need to be any longer than say 1/8" - 1/4") , and machine a corresponding shallow mortise in the headblock, purely for purposes of accurate neck location, not from any structural vewpoint.

Or is such a tenon/mortise unnecessary, and the accurate drilling of the holes for the hanger bolts ( or for the threaded inserts) provides sufficiently accurate registration?

I use a 1/2" tenon, but I don't think a tenon is necessary.
My reasons for using a tenon.
1. I do alot of dovetails. Many of my clients are traditionalists, and prefer them. They're also simple, meaning no dowel through the neck, and no chasing down hardware. I use a 1/2" dovetail, so I can cut my neck blanks the same way to use a 1/2" tenon with a bolt on.

2. A 1/2" tenon is long enough to keep the bolts out of the actual heel. I only install strap buttons if the client requests them. I don't want someone to have their screw run into the neck bolt if they don't put in the the right place.

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I didn't mean to say it, but I meant what I said.
http://www.brackettinstruments.com/

I have used a butt joint on my last two - one of them a 12 string - with threaded inserts and don't think I'll be going back to a M&T anytime soon.
I too was a little concerned with possibility of sideways movement at the neck heel, but believe me, once bolted up, you'd have to hit it sideways with a mallet really hard to stand any chance of moving it.

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http://www.bobmatthewsguitars.co.uk

I’ve decided I am going to give the butt joint a try. I do like the idea of building up the tenon and rerouting the angle to correct the error. That is a really good option. If I had already routed the mortise in the body, I would go with that.

However, I see quite a few advantages for ease of fitting with the butt joint. Additionally I don’t have to route the mortise in the body. I’m sure glad I made this mistake on the neck blank rather than on the mostly done body. Overall, the butt joint looks like a simple joint.

Before I route the rest of the tenon from the neck, I’m going to make sure I will be able to set the threaded insert square into the neck. If that doesn’t work I’ll move on to the hanger bolt approach. I’m on the fence as to which one I’m going to use. After doing some tests and determining the right size hole to drill, I’ll decide. I’m thinking I can use the neck angle jig and the drill press to square things up. I just need to practice a bit.

Well I think I hit the point of this build where nothing is going to go easy.

I decided to use threaded inserts for my neck joint. I went ahead and routed off the crooked tenon. My neck angle looks good so I’m happy with that. I have everything setup to install the inserts and feel comfortable doing that.

I decided that I would put a ½” hardwood dowel in the heel so that the inserts were not just threaded into end grain. I drilled the hole and installed the dowel, but in the process I have created a crack in the face of the heel.
This is a stacked heel and the crack only hits the middle two blocks in the stack. The neck shaft block and the heel cap block have not cracked.


I haven’t tried very hard, but I don’t’ think I can close this crack with a clamp.

I can think of a few options here.
I could either flood with CA or work in some epoxy and move on. Or I could drill this out and try again.

I really wish I had just installed the inserts and left it alone.

Flood with CA. I had the same problem on a tenon a few years ago. I flooded with CA and put threaded inserts in without a dowel. Been 5 years now and no problems yet.

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ELEVATE || Next Level Lutherie
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Did you drill the hole for the dowel all the way through John? If you dead ended the hole, then the glue has nowhere to escape and the pressure can cause the cracking. You also have to make sure that the fit of the dowel is tight but not too tight. I use a hole drilled through a metal plate to size my dowels for a good fit as commercial dowels can easily vary by .005 to .020".