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Why I like butt joints...
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Author:  meddlingfool [ Mon May 04, 2015 2:34 pm ]
Post subject:  Why I like butt joints...
I recently got a guitar back for a crack fix.

It's a fairly new guitar that had done some settling. I noticed that either from the top coming up, or the neck coming forward, the neck angle was no longer perfect.

So I got a chance to test a theory, the theory being that with a bolt on butt joint, you could do a reset without even needing to unglue the extension,

This is why I prefer furniture bolts over hangar bolts.

Take out the bolts...Image

Insert packing tape backed paper...Image

Do your flossy business, and...Image

Boom! 5 minutes, no muss, no fuss, pulled the angle back 1/16" at the bridge, and it's still a nice clean perfect joint!
Author:  Chris Pile [ Mon May 04, 2015 2:38 pm ]
Post subject:  Re: Why I like butt joints...
YOU DA MAN!
Author:  Hesh [ Mon May 04, 2015 2:53 pm ]
Post subject:  Re: Why I like butt joints...
Ed's a butt man! :)

Nicely done and a great shot of a beautiful flossing/fit job.

You can do this with a mortice and tenon too and it's been being done now for as long as there have been mortice and tenon joints.

Tale of two guitars: Recently we took in a Martin that needed a warranty neck reset and a Taylor that needed a warranty neck replacement.

The Martin was a dovetail and the Taylor was a bolt-on. The Taylor took less than 40 minutes to do, the Martin took hours..... Nuff said.
Author:  meddlingfool [ Mon May 04, 2015 3:14 pm ]
Post subject:  Re: Why I like butt joints...
That guitar also 'features' a homemade 1/4x20 strap button. Some idiot drove the bottom bolt right into the heel wood, popping a perfect little circle out. :)

And yes, you can do this with a m&t, as well as with hangar bolts. But in each of those cases, you have to do each side separately, count your strokes etc., and deal with the little nib in the middle of the heelcap that happens.

With the bolts out in this case, you can do both sides and the heelcap all at once. Me like!
Author:  Hesh [ Mon May 04, 2015 3:43 pm ]
Post subject:  Re: Why I like butt joints...
Nice Ed!

Strap buttons can be a nightmare for individual Luthiers.... Not because they are ugly or not because some don't like em but because some mouth breather in a music store who can't even use a screw driver properly will invariably attempt to install one in the wrong place perhaps hitting a neck bolt or insert.... Don't these people very learn.... :)
Author:  Bryan Bear [ Mon May 04, 2015 4:20 pm ]
Post subject:  Re: Why I like butt joints...
As you said, you can do this with M&Ts and hangar bolts but it is a bit more involved because you have to do each side separately and keep an eye on the yaw of the neck. The middle of the heel cap is a bit of a pain too. All that said, I like and use hangar bolts because I end up with less hardware in the heel. I have long suspected that tapping machine threads into the cross grained hardwood dowel would be more than up to the challenge of holding a butt joint but have not gotten around to testing this. Seems like it could be a best of both worlds situation.
Author:  meddlingfool [ Mon May 04, 2015 5:35 pm ]
Post subject:  Re: Why I like butt joints...
I've used dowels from time to time, but I stopped. I saturate the area around the inserts with thin CA, and find it holds just fine. I guess dowels would be 'better', but if the neck stays on without it (and it does), it's just one more step...
Author:  Pmaj7 [ Mon May 04, 2015 8:48 pm ]
Post subject:  Re: Why I like butt joints...
Sweet!

meddlingfool wrote:
I saturate the area around the inserts with thin CA...

I do this too but always worry it's going to run through. Ever had that happen?
Author:  Bryan Bear [ Mon May 04, 2015 9:30 pm ]
Post subject:  Re: Why I like butt joints...
So the inserts hold in endgrain okay? That makes me even more confident that machine screws into a dowel would be sufficient. I like the dowles because, as I understand it, it also works to help prevent the heel form splitting. I suppose I should get around to testing my idea.
Author:  Sankey Guitars [ Mon May 04, 2015 9:52 pm ]
Post subject:  Re: Why I like butt joints...
Yeah, I've done machine screws into endgrain plenty of times. Drill, tap, saturate with thin CA, tap again. I've used 1/4-20 threads and it's plenty strong enough for the worst abuse (I've tested this. It was fun.) The only issue is that it's probably easier to get it cross-threaded when said mouthbreather tries to do a reset, and that will definitely ruin the strength. Of course, if that happens you can still install some inserts.
Author:  James Orr [ Mon May 04, 2015 10:10 pm ]
Post subject:  Re: Why I like butt joints...
Ed, nicely done!

Machine screw guys - are you saying you just screw the machine screws straight into the hardwood dowel/reinforcement after quirting in some CA and letting it dry?
Author:  meddlingfool [ Mon May 04, 2015 10:12 pm ]
Post subject:  Re: Why I like butt joints...
The inserts hold in end grain just fine.

Yes, the ca can wick all the way through but it blends seamlessly under finish...
Author:  Bryan Bear [ Mon May 04, 2015 10:28 pm ]
Post subject:  Re: Why I like butt joints...
Mike, as a mouth breather I'll try not to take offense:) I assume you tap the holes first.?.

Thanks Ed, I too sick in ca with my hangar bolts and agree the bleed though disappears when finishing. The endgrain is pretty forgiving in that respect.
Author:  jfmckenna [ Tue May 05, 2015 8:24 am ]
Post subject:  Re: Why I like butt joints...
I use the butt joint too. I may go the dowel rout on my version 2.0 guitars coming soon. One of my earlier ones has developed movement on the heal. Not cracked but the glue joints for the stacked heal are showing if ya know what I mean. I attribute that to the weakness of the inserts but I cannot be sure. Anyway I epoxy the inserts in and set them in about 1/8th inch for future resets.
Author:  James Orr [ Tue May 05, 2015 10:21 am ]
Post subject:  Re: Why I like butt joints...
Just to clarify my question, all of my necks have threaded inserts CA'd into the end-grain. They've all been purchased commercially.

I am planning to make my own necks from here on out, using a butt joint with threaded inserts CA'd into a hardwood dowel inserted into the heel.

It sounds like some of you aren't using the threaded inserts, simply sending the machine screws into the end-grain and reinforcing the threads with CA. Am I reading this correctly?

Sankey Guitars wrote:
Yeah, I've done machine screws into endgrain plenty of times. Drill, tap, saturate with thin CA, tap again.
Author:  Bryan Bear [ Tue May 05, 2015 11:03 am ]
Post subject:  Re: Why I like butt joints...
In the interest of accuracy, I have not yet done the machine screw into the heel. I was only thinking that it would probably work (no real world experience). It looks like Mike has done it which gives me more confidence to push forward. I will still use a cross grain dowel when I attempt this. I will also likely do some testing before I do it on a guitar.
Author:  James Orr [ Tue May 05, 2015 11:56 am ]
Post subject:  Re: Why I like butt joints...
Thanks, Bryan. I'm all about increased simplicity! I'll probably err on the cautious side on the first go-round though.


Sent from my iPhone using Tapatalk
Author:  Mark Mc [ Tue May 05, 2015 3:00 pm ]
Post subject:  Re: Why I like butt joints...
Nice one Ed.
I am currently building with exactly the same set-up for a butt joint with threaded inserts. But also with a bolt down fastning of the fingerboard extension. It is not too hard to do and you get a true detachable neck.

BTW - what did you use for those side dot fret position markers? Is it brass tubing? They look nice!
cheers
Mark
Author:  meddlingfool [ Tue May 05, 2015 7:16 pm ]
Post subject:  Re: Why I like butt joints...
Aluminum and brass.

I did a bolt down tongue for a while but found they shifted forward rapidly. I think the shear strength of a glued extension helps a lot.
Author:  jfmckenna [ Tue May 05, 2015 9:36 pm ]
Post subject:  Re: Why I like butt joints...
meddlingfool wrote:
Aluminum and brass.

I did a bolt down tongue for a while but found they shifted forward rapidly. I think the shear strength of a glued extension helps a lot.


And it's not really all that hard to un-glue either. 5 to 10 minutes under a heat lamp with a spatula and done.
Author:  meddlingfool [ Tue May 05, 2015 9:49 pm ]
Post subject:  Re: Why I like butt joints...
That's what I hope. I also only use a very thin 1/16 bead around only the perimeter.
Author:  Bryan Bear [ Wed May 06, 2015 10:50 am ]
Post subject:  Re: Why I like butt joints...
James Orr wrote:
Thanks, Bryan. I'm all about increased simplicity! I'll probably err on the cautious side on the first go-round though.


Sent from my iPhone using Tapatalk



James, I just saw your earlier question and realized that I still left a bit of info out of my answer. I have not yet done the machine screw into the hardwood dowel but I have been doing bolt on butt joints without inserts using hangar bolts. By design, the wood threaded end of the hangar bolt wold be expected to hold in the heel (just as the wood treads of the insert would) but I was postulating that the hardwood dowel could also be tapped with machine threads and that those threads (in wood) would also be up to the task with the forces involved. As I see it, the only advantages the threaded inserts have over the hangar bolts is that it is slightly easier to floss the heel since the bolts can be taken out of the way. The advantage to the hangar bolt is the smaller intrusion into the wood of the heel allowing for a slightly slimmer heel. Tapping machine threads into the heel would seem to have the benefits of both and the added bonus of only having to by one piece of hardware.
Author:  TimAllen [ Wed May 06, 2015 11:49 am ]
Post subject:  Re: Why I like butt joints...
Excellent points in this thread.

FWIW, it's easy to back out a hanger bolt by putting two nuts on it, jammed together. A dozen times might strip the hole, but a few times seems fine in my limited experience, with a walnut or mahogany neck, maple dowel, and epoxy-lined hole.

I use hanger bolts in my guitars, hangar bolts in my airplane sheds. :D
Author:  meddlingfool [ Wed May 06, 2015 1:56 pm ]
Post subject:  Re: Why I like butt joints...
Heh, wasn't sure about that...
Author:  James Orr [ Wed May 06, 2015 2:07 pm ]
Post subject:  Re: Why I like butt joints...
meddlingfool wrote:
Aluminum and brass.


I love the look. Was it difficult to get them level with the fretboard binding? Whenever I think about doing this, I worry that the dot and binding will sand unevenly.
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