Loose Tenon ::: Any Downsides?

Brett S. · Feb 25, 2020

I have been using mortise and tenon joints for my ukes, so far, with bolts and the tenons *not* glued into the body/block.

On my current build, a mishap wrecked the tenon on the neck, so I cut it off and reworked it to have a loose tenon. (I don't yet have a photo of this, but could in the near future) It made the neck fitting to body really easy, and no doubt the best fitting neck I've done yet.

I'm starting to think of doing this again. What I decided to do was epoxy the loose tenon into the neck, and it has a threaded brass insert for a bolt. The epoxy cured, and I fit the neck to the body for the first time yesterday, and voila! Perfect fit.

Can anyone think of any downsides to doing it this way?

Uke-alot · Feb 26, 2020

Can't think of a downside as long as you have an accurate way to make the mortise in the neck (which apparently you do, since it worked out). I assume you have a jig to make the mortise. But I'm wondering why you used epoxy instead of wood glue for the loose tenon.

Edit: On second thought, on old banjos, the glue on the dowel can start to fail after a few decades. This is the part that extends from the base of the neck all the way to the other end of the banjo pot. That can make the neck loose, and the action increases due to string tension acting on the now-loose joint. So this is a possible downside, but it's unlikely to manifest itself for a long, long time as long as the mortise/tenon fit is good and it's well-glued.

Brett S. · Feb 26, 2020

Uke-alot said:
Can't think of a downside as long as you have an accurate way to make the mortise in the neck (which apparently you do, since it worked out). I assume you have a jig to make the mortise. But I'm wondering why you used epoxy instead of wood glue for the loose tenon.

I have been making my mortises by hand mostly but will like to someday have a more solid method, but so far, so good.

Why expoxy? I thought lots of end grain and the tenon as more of a permanent part of the neck. But if I omitted the bolt I would have likely just used wood glue to put it all together.

printer2 · Feb 26, 2020

A few custom guitar makers no longer cut a tenon, instead they accurately position holes and bolts from the neck through the neck block. But they use two bolts and do not glue the neck to the body. I took a guitar apart which is representative of cheaper guitars out of the East, they use dowels to position but glue the face of the heel to the body. If I can get my act together and get everything accurate I think I will use hanger bolts in the neck and through the body.

Timbuck · Feb 26, 2020

Have a bit of fun and do compound dovetails instead...It makes you feel good when you get it right

Brett S. · Feb 26, 2020

printer2 said:
A few custom guitar makers no longer cut a tenon, instead they accurately position holes and bolts from the neck through the neck block. But they use two bolts and do not glue the neck to the body. I took a guitar apart which is representative of cheaper guitars out of the East, they use dowels to position but glue the face of the heel to the body. If I can get my act together and get everything accurate I think I will use hanger bolts in the neck and through the body.

Interesting, do you recall who those makers are?

Timbuck · Feb 26, 2020

Brett S. said:
Interesting, do you recall who those makers are?

In the UK we call Hanger bolts Dowel Screws.

printer2 · Feb 26, 2020

Brett S. said:
Interesting, do you recall who those makers are?

The hanger bolts or the dowels? The dowels, Aria for one. The tenonless guitar, Stephen Kinnaird, the guitar is being finished and as bad as the picture is you can see there is no joint cut out of the neck area.

Halcyon Guitars also, can't find pictures either.

Brett S. · Feb 27, 2020

printer2 said:
The hanger bolts or the dowels? The dowels, Aria for one. The tenonless guitar, Stephen Kinnaird, the guitar is being finished and as bad as the picture is you can see there is no joint cut out of the neck area.

Halcyon Guitars also, can't find pictures either.

Yes, I meant the guitar makers. Thanks. Interesting.

jcalkin · Feb 28, 2020

Huss & Dalton is another guitar company that uses no neck tenon, brass inserts directly into the neck, and two bolts through the neck block. I would never consider any other method, though I have lately switched to threaded steel dowels in the neck rather than inserts on my ukes, and only one bolt.

Brett S. · Feb 28, 2020

wow

jcalkin said:
Huss & Dalton is another guitar company that uses no neck tenon, brass inserts directly into the neck, and two bolts through the neck block. I would never consider any other method, though I have lately switched to threaded steel dowels in the neck rather than inserts on my ukes, and only one bolt.

Thanks for this! It's an eye opener. And Printer2.

Beau Hannam Ukuleles · Feb 28, 2020

You should probably define your definition of "Loose". For some, loose means 1/64th (0.5mm) gap, for others a 2mm gap.

Sometimes I over cut one side of a tenon and/or it gets routed and the center of the tenon is misaligned to the body center line.

In such instances, I CA glue a shim (a piece of 0.020") to one side of the tenon to pack it out so i get a tightish fit.

It's not so tight that I can pick up the body by the neck without bolts. But there is decent wood/wood contact.

After I put in the inserts, I flood the tenon with thin ca glue to solidify the entire area. (I have youtube videos of this whole procedure)

Brett S. · Feb 28, 2020

Beau Hannam Ukuleles said:
You should probably define your definition of "Loose". For some, loose means 1/64th (0.5mm) gap, for others a 2mm gap.

Sometimes I over cut one side of a tenon and/or it gets routed and the center of the tenon is misaligned to the body center line.

In such instances, I CA glue a shim (a piece of 0.020") to one side of the tenon to pack it out so i get a tightish fit.

It's not so tight that I can pick up the body by the neck without bolts. But there is decent wood/wood contact.

After I put in the inserts, I flood the tenon with thin ca glue to solidify the entire area. (I have youtube videos of this whole procedure)

By "loose tenon" I mean that the tenon is not an extension of the neck (same block of wood), but a separate piece from the neck and the body. The fit was was very good, a good friction fit. I epoxy-ed the tenon into the neck, into a mortise/pocket created in the heel of the neck. I should have provided a picture but I still haven't gotten back to that.

bazuku · Feb 28, 2020

Although either term is equally correct, I prefer to call loose tenons, floating tenons. The loose tenon always sounds like an ego-damaging admission of sloppy joinery

Loose Tenon ::: Any Downsides?

Brett S.

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