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Well I cut wrong need advise
http://mowrystrings.luthiersforum.com/forum/viewtopic.php?f=10101&t=54544		 Page 1 of 2
Author:  SnowManSnow [ Mon Nov 15, 2021 9:10 pm ]
Post subject:  Well I cut wrong need advise
I cut on the wrong line.. and as a result my tenon is only 1/2” . Is this too shallow?
I generally use 10mm barrel bolts to do my bolt on. It would still fit but ho early won’t leave a lot to grip

Should I try to extend the tenon w a glue on?

Or should i scrap it?

Hanging my head after making a dumb mistake


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Author:  Dave Livermore [ Mon Nov 15, 2021 9:16 pm ]
Post subject:  Re: Well I cut wrong need advis
Include a couple pictures please.

Easier to give advice if we can see what you got yourself into
Author:  Clay S. [ Tue Nov 16, 2021 12:00 am ]
Post subject:  Re: Well I cut wrong need advise
You could do a loose tenon, and maybe even improve the grain orientation of the tenon by turning the grain 90 degrees to the grain of the neck:
https://www.woodcraft.com/blog_entries/ ... on-joinery

One difference from what is shown is that you would only glue the tenon into the neck and bolt it to the body.
Author:  DennisK [ Tue Nov 16, 2021 12:24 am ]
Post subject:  Re: Well I cut wrong need advise
Option 1: Hack that tenon off and convert to butt joint.
Option 2: Use Gore style square bar instead of barrel bolts http://www.luthiersforum.com/forum/viewtopic.php?p=715113#p715113
Author:  Colin North [ Tue Nov 16, 2021 3:09 am ]
Post subject:  Re: Well I cut wrong need advise
Yup, Gore style if you have access to a 10mm or maybe 3/8" mortice drill.
Author:  joshnothing [ Tue Nov 16, 2021 6:01 am ]
Post subject:  Well I cut wrong need advise
Trevor does post here on occasion so he may correct me on this but I believe the bolt bar may have originated with his co-author Gerard Gilet, or at least have been a collaborative effort between them both.

(Also once you try bolt-bar, you won’t go back :D )
Author:  surveyor [ Tue Nov 16, 2021 9:59 am ]
Post subject:  Re: Well I cut wrong need advise
It sounds like your using the "Cumpiano " style bolt on mortise and tenon. Just make 2 thin plates the correct size of the side of the tenon that you originally wanted, cut down the tenon thickness to accommodate them and add a block on the end to fill up what was accidentally cut off and glue it all up. Also you can improve it by turning the grain of the "plates" 90deg. to the end grain of the neck for added strength. I make mine like that all the time, except I try not to have the little block on the end.
Author:  Bob Orr [ Tue Nov 16, 2021 10:43 am ]
Post subject:  Re: Well I cut wrong need advise
I reinforce my tenons by gluing on a strip of thin aero modellers ply on each side of the tenon. I use 1.5mm thick which may help with Mike Spectors suggestion.
Author:  SnowManSnow [ Tue Nov 16, 2021 10:55 am ]
Post subject:  Re: Well I cut wrong need advise
Hey guys sorry I haven’t responded yet.
I’m at work so I can’t snap a pic, but the issue is the tenon is too short. I like a 7/8” tenon vertically.
To use the 10mm barrel nut will leave too little wood on the bottom (under the nut) and I fear it would pull out eventually, although probably not.

As the suggestions above … I could reinforce the sides of the tenon so that the dyes of the barrel nut are grabbing onto that, or possibly glue an extension onto the end of the tenon so that it sits perfectly in the mortis and has no where to go. For that matter I could just cut a shallower mortis and achieve the same thing . The mortis hasn’t been cut


This, as with most things I mess up can be rectified ha.
See the high tech illustration below
Image


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Author:  meddlingfool [ Tue Nov 16, 2021 12:09 pm ]
Post subject:  Re: Well I cut wrong need advise
TBH, I think your neck is lost unless you find some radical save. FWIW, when I still did a tenon, I would glue on a cap of rosewood or maple to the face of the blank before I routed the tenon. I know it's not proper joinery to glue to end grain, but, it seemed effective to prevent the barrel nuts from splitting the tenon. While most folk seem to reinforce that area by adding shims to the sides or the tenon, adding meat to the end did seem to work. YMMV.
Author:  meddlingfool [ Tue Nov 16, 2021 12:18 pm ]
Post subject:  Re: Well I cut wrong need advise
Also, if you haven't shaped the heel, you could perhaps try a butt joint with threaded inserts...

Sure, you'd have bolts going through a lot of empty air but so what.
Author:  DennisK [ Tue Nov 16, 2021 12:45 pm ]
Post subject:  Re: Well I cut wrong need advise
Actually you could drill a round hole down the heel and install the barrel nuts vertically like the square bolt bar. Drill a couple of small holes through the tenon from the side and glue dowels to eliminate any possibility of splitting.
Author:  Jim Watts [ Tue Nov 16, 2021 1:09 pm ]
Post subject:  Re: Well I cut wrong need advise
You also could lay on some carbon fiber or glass on the end of the tenon to strengthen it.
All of the above suggestions seem practical to me.
Author:  banjopicks [ Tue Nov 16, 2021 1:39 pm ]
Post subject:  Re: Well I cut wrong need advise
Switch to hanger bolts for this one and be done.
Author:  Trevor Gore [ Tue Nov 16, 2021 4:03 pm ]
Post subject:  Re: Well I cut wrong need advise
joshnothing wrote:
Trevor does post here on occasion so he may correct me on this but I believe the bolt bar may have originated with his co-author Gerard Gilet, or at least have been a collaborative effort between them both.

(Also once you try bolt-bar, you won’t go back :D )


Yes, the square section bolt bar originated with Gerard with the bolt-on, glued down fret board neck joint, sometime in the 1970s, I believe. I developed the concept into the bolt-on, bolt-off neck joint (double tenon with bolt down fret board extension) some 35 years later.
Author:  David Newton [ Tue Nov 16, 2021 8:39 pm ]
Post subject:  Re: Well I cut wrong need advise
I had a "student" builder who would bring his guitar parts to my shop for tips on his next steps. He built three necks before he got it right.
Even though I hate it, I toss a part from time to time.
Author:  rlrhett [ Tue Nov 16, 2021 11:42 pm ]
Post subject:  Re: Well I cut wrong need advise
I tend to keep the mistakes hanging on the wall as a reminder. I finally tossed a half dozen necks this summer because I realized I don’t need THAT many reminders. :-0


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Author:  Clay S. [ Wed Nov 17, 2021 7:20 am ]
Post subject:  Re: Well I cut wrong need advise
If there weren't so many good options for rectifying the relatively minor mistake, then I might agree that tossing or repurposing the neck might be the best option. Since the mortise has not been cut, removing the tenon and making a simple butt joint with inserts or hanger bolts would work fine. If keeping the tenon and barrel nut is wanted then making a loose tenon and turning the grain90 degrees to the wood in the heel would actually make a stronger fastening than the usual one piece construction.
To learn from your mistakes you sometimes need to overcome them. [:Y:]
Author:  David Newton [ Wed Nov 17, 2021 4:34 pm ]
Post subject:  Re: Well I cut wrong need advise
I don't disagree with you Clay, especially if the OP is a learner. Just the idea of wanting to use the mortice and tenon joint, and switching over to a bolted butt, being a "bridge too far". There is something liberating about starting over. In my early days, starting over was how I proved to myself that I could build the guitar I wanted to build.
Author:  Bryan Bear [ Wed Nov 17, 2021 4:55 pm ]
Post subject:  Re: Well I cut wrong need advise
True David. The other side of that coin is that sometimes recovering from mistakes opens up your repertoire.


This could be an opportunity to try a butt joint and decide he likes it. Not much to lose but time if starting over is the alternative. Arguments on both sides have merit; it is up to each of us to weigh these types of things out for ourselves. That is one of the things I love about this forum. If you post a problem, you get lots of different approaches from lots of people. Some may work better for your personality and situation than others but considering all of them really can open up your eyes to techniques you hadn't considered.
Author:  Clay S. [ Wed Nov 17, 2021 9:26 pm ]
Post subject:  Re: Well I cut wrong need advise
One of the drawbacks of the barrel nut/ bolted tenon as I see it is that the grain of the tenon is going in the "wrong" direction. By cutting a mortise in both the neck and the body the "loose tenon" can have the grain oriented in a better position and a stronger construction made. If I were to do bolt-ons with tenons that is how I would do them.
But I am the lazy sort and I don't feel barrel nuts installed in tenons as they are conventionally made are any stronger, I generally do butt joints with inserts.
Author:  SnowManSnow [ Wed Nov 17, 2021 9:46 pm ]
Post subject:  Re: Well I cut wrong need advise
Thanks for suggestions guys. I think I can keep the neck. Ill experiment and see what I can come up with.
Still can’t believe I made that mistake :)
That said I don’t look to make it again.
1 out of 25 isn’t bad I guess


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Author:  SnowManSnow [ Wed Nov 17, 2021 9:48 pm ]
Post subject:  Re: Well I cut wrong need advise
Clay S. wrote:
If there weren't so many good options for rectifying the relatively minor mistake, then I might agree that tossing or repurposing the neck might be the best option. Since the mortise has not been cut, removing the tenon and making a simple butt joint with inserts or hanger bolts would work fine. If keeping the tenon and barrel nut is wanted then making a loose tenon and turning the grain90 degrees to the wood in the heel would actually make a stronger fastening than the usual one piece construction.
To learn from your mistakes you sometimes need to overcome them. [:Y:]

Googling loose tenon


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Author:  J De Rocher [ Wed Nov 17, 2021 9:52 pm ]
Post subject:  Re: Well I cut wrong need advise
I'm thinking that a loose tenon is the same thing as a floating tenon? Neither of which is loose or floating.
Author:  SnowManSnow [ Wed Nov 17, 2021 11:17 pm ]
Post subject:  Re: Well I cut wrong need advise
J De Rocher wrote:
I'm thinking that a loose tenon is the same thing as a floating tenon? Neither of which is loose or floating.

Yea I’m finding that out:) a floating tenon should be floating:) I mean….


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