Official Luthiers Forum!

Guys another question for you I'm building from Kinkheads plans, but am gonna use Cumpianos bolt on neck design my only questions are which type of nut to use in the tenon for the joint.

A Cross Dowel


Or a Nut Insert


I have a feeling both are as good as each other and it's a apples and oranges question again

Do either have merits in the way the pull in relation to the grain?

Thanks

John

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Formerly JJH

I learn more from my mistakes than my successes

If you are going to use a tennon, I would use the cross dowel
I have used the threaded insert epoxied in place with a straight butt joint and it was fine, would not trust it in end grain otherwise.

The nut insert pictured is specifically designed for end grain, 3/8" hole, it works. A lot of builders use it, chamfering the hole lightly allows to wick some CA between the outside threads and the wood. Clamp your tenon when to screw the insert in to avoid splitting.

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

I use LMI's neck hardware. I drill a 1/2" hole for an oak dowel straight down the tenon so that the inserts rest half in the end grain of the neck and half in the straight grain of the dowel - after the inserts are in, I wick thin CA into the holes.

If you separated the pull from the string into vectors, I bet there wouldn't be much to life the neck away from the body. I think either system if installed correctly will be far more structurally sound than what is required.

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Simon

The nut insert will work just fine and is alot easier to install. When you install the inserts just clamp the edges of the tenon to prohibit any cracking and wax the threads of the insert with beeswax. It does not need any glue. I have done hundreds that way and none have loosened. Good luck!

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Sylvan
http://www.wellsguitars.com

The CA prevents the nut from twisting should the guitar come apart at a later date.

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

I prefer these:

These are steel. I think the ones with the broken threads are a zinc casting. Those don't seem to me to be as strong, and their threads are definitely not as sharp.

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Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

Where do you get those Howard?

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

I agree with Todd. The barrel nuts can rotate to line up with the plane of the attachment bolts. The end of the tenon is usually tilted a little in the mortise corresponding with the angle of the neck. The barrel nuts can rotate to match that angle so the bolts hit them as a straight shot. Probably doesn't make any real difference which approach you use in reality but I do like the way they work.
Terry

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

In that case barrell nuts it is as a first build I bound to get it a little out , and if these can take that I'll head in that direction, perhaps a strip of wood glued either side of the tenon with the grain running at 90 degrees to the grain of the neck will get over the problem i was concerned about

Cheers Guys

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Formerly JJH

I learn more from my mistakes than my successes

I started using barrel nuts 4 guitars ago and love them for all the reasons stated. I drill for them in the drill press while the neck layup is still square and before the tenon has been milled. Has anyone ever drilled these once the tenon is formed?

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JJ
Napa, CA
http://www.DonohueGuitars.com

I use the barrells also,they work great.And JJ ,I did drill them after the neck was formed once, but went back to drilling while square in the drill press.It is much simpler and more accurate.Also 1" 1/4 bolts can be bought at Rockler.But their barrells have holes that are off-set from center which I don`t like,so I get those at the Borg. James

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James W Bolan
Nashville Tennessee

McFeeley's. They are also shown in the McMaster-Carr online catalog, in a choice of lengths.

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Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

I've got a couple of jigs I copied from a Mark Swanson post on MIMF a few years ago.
One is a male tenon that has drill guides and fits in the neck block mortise to drill those holes. (5/16") The other is a female mortise that has 5/16" drill guides for the 1/4" bolts and 3/8" drill guides for the barrel nuts. ( I couldn't find 10mm drill guides) I have to enlarge them to 10mm starting with a tapered reamer and then a 10mm drill bit in reverse.
I fit the neck after the tenon is cut with the fretboard clamped on and use transfer punches to mark the starting points of the holes. Align and clamp the jig and drill the holes. The transfer punch can also be used to align the second jig. I flood the area of the holes with thin CA to stiffen them. So far no failures. The 5/16"holes and 1/4"bolts factor a little forgiveness into the system. (By the way Ace Hardware has the 10mm barrel nuts with a centered hole.)
Terry

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

Howard: I'd agree in theory, but having done a few 'destroy' tests with both types, found no significant differences (both were near impossible to wreck), but those are more difficult to drive in cleanly and I found them more likely to crack/strip the wood than the other inserts.

Just for curiosity sake for you guys using threaded inserts, how much under thread pitch diameter are you drilling to?

Which ones are you calling "those?"

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Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

Howard, I think these are the "those" Mattia is refurring to.

I took the liberty of Photoshopping a replica of what "those" look like after grinding knotches through the first few threds. I do this to both sides of "those" so they "cut in" as you insert them. You are less likely to get cracks that way. I think they call this "self tapping".

Wade

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Wade
Nashua, NH
http://www.wadefx.com

Thanks Wade. As for driving them, the way to go is to use a drill press (turned by hand) to keep them aligned.

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Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

Nice jig Terry/Mark...thanks for posting.

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JJ
Napa, CA
http://www.DonohueGuitars.com

I have used both and I have found the barrel to superior, It only took one time of having the treaded insert strip out the wood to make up my mind. Plus I can make my own barrel nuts in house.
Jeremy

I prefer these also. I tried the barrel nuts and don't like them. Yes, there is a learning curve to using these treaded inserts, but once you find the right drill size and have a good technique to keep things square, for me they are much easier than barrel nuts.
I use fish glue as a lubricant when I thread then into the wood - wax works well, but I'd rather have something that will help hold and stabilize the insert.

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"An adventure is only an inconvenience rightly considered. An inconvenience is an adventure wrongly considered." G. K. Chesterton.

Terry, where'd ya get those drill guides from? I'd be interested to know....ta very much!

Dave F.

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Cambrian Guitars

"There goes Mister Tic-Tac out the back with some bric-brac from the knick-knack rack"

[quote="ToddStock"]J

Been there! I now hold the neck very carefully when wicking it in and then clamp in in a vise tilting down a little while it sets up.
Terry

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