Official Luthiers Forum!

Last night I attempted to install the LMII inserts on the first neck I ever carved. Not a stellar success--the tenon and heel cracked when I was installing the bottom insert and now the neck is in two pieces. With the LMII system, a threaded insert is installed into a 10 mm holed drilled with a brad point bit, which, if my math is right is almost .4". With a .75" wide tenon, this only leaves .175" of the tenon on either side of the insert. Adding the width of the threads reduces this even more. They also recommend that that you clamp pieces of wood to the tenon, presumably to prevent cracking which I suspect has occurred before, which I did and it did. Besides the time and expense of buying another neck blank, I'm leery of using LMII's system again unless someone can tell me that I did something fundamentally wrong. Do many people use LMII's hardware? If not, what do you all use for bolt-on necks and what is your procedure for installing them?

Steve

I use cross dowels as developed by Bill Campiano, he has some detailed instructions on his site along with where to source them on the USA.

I'll Post a link in a minute.

I use similar hardware, but I purchase it at the local Ace Hardware store at a much lower price. I use a slightly oversized hole then I thread the insert onto an allen head bolt with a nut allready installed on it. I tighten the nut against the insert, then carefully thread the insert into the wood. It must be straight. If it is running at an angle it will crack the neck. I also run it in a bit then back it out then start over sort of like using a tap. I don't just crank it in. Once it's to full depth I back off the nut then remove the screw then apply a few drops of thin CA to lock it in place.

Al

Hear you go Steve

William Campiano Article

[QUOTE=RussellR] Steve

I use cross dowels as developed by Bill Campiano, he has some detailed instructions on his site along with where to source them on the USA..[/QUOTE]

I like this system.It works very well.

_________________
Anderson Guitars
Clearwater,Fl. 33755

     The use of dowels to strengthen a joint is a great way . However if you make the hole too tight you can still damage the neck. Use the proper hole . I use the same insert martin uses and have had great success with them.
john hall
blues creek gutiars

Steve,

I had this happen once. It was a solid neck and I only cracked the tenon a bit. I had installed the insert upside down. The sloted end goes in first. It cuts the thread. This may or may not be what happen in your case but it is a possability.

Cecil

I don't think I can repair it as the break is right through the hole where the insert was going. While the surface appearance would not bother me or I could use it on a beater for the shop, I don't think I the insert would be structurally sound.

On my two previous guitars, I used precarved necks which had hangar bolts installed. Guess I need to think this all through to decide what method I think will work best for me. Frustrating and discouraging, to say the least. Thanks to everyone for the help and suggestions.

Steve,
Don't scrap the neck. Glue it back together. Drill a deeper 1/2" hole where the 10mm hole is and glue in a 1/2" dowel. I have nice brass threaded inserts that have threads that are not as big that I'll send you for free. Just PM me your address. I'll let you know what size to drill the new hole.

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

Steve

Another method of repair is to replace the whole tennon cut off the tennon and then route a slot and glue in a piece of material ? Alternately if the heel is damaged can you replace the heel and slot in an insert to create the tennon.

Stephen, the very same thing happened to me on no 2! All i did was to make a plug or dowell? that i glued in!

I'll try to repair it with a dowel. No downside and maybe it will be salvageable. It'll also give something to do today. Thanks again.

Steve: I'll send you a PM with my address. Really appreciate it.

Oh and by the way Stephen, if you buy a strap button from Stew Mac, it will hide any spots from a difference of color from that dowell you'll be using...

Why use a tenon at all?

Life's complicated enough already. Simplify, my friends, simplify.

I used barrell bolts you can buy from Lowe`s or any where.This technique is used on Robbie O`Briens video.It`s completely idiot proof.Works great for mortise and tenon .     James W B   

_________________
James W Bolan
Nashville Tennessee

[QUOTE=Mario] Why use a tenon at all?

Life's complicated enough already. Simplify, my friends, simplify.[/QUOTE]

Right you are again Coach! i guess i'm hard headed, will definitely go with the butt joint that you use next time around, a whole lot less measuring and fitting me thinks!

Mario--I went to your web site to look at how you do your heels and I see you put a dowel vertically through the heel. Is this just for giving the inserts something stronger than mahogany to bite into or are there other reasons.

The best way I've found is to pre-tap the holes. This allows you to make your hole smaller to start with and just about completely elimates the possibility of splitting.

Taps in the needed size are not commercially available, so I made mine. I made two t-handle wrenches. One for tapping the hole, and one for installing the insert. They're about 8 inches long to make it easier to keep it going straight.

I'm going to be offering a kit once I get caught up that will include the wrenches, a hard to find but perfectly sized drill bit (.336") and a hundred or so of the best inserts (I've tried them all).

It makes for a worry-free job with a clean look.

_________________
John Watkins
CNC Guitar Parts

WOW jOHN,that is very cool, it will make a very neat job!

Hey John....
The mahogany on the right edge of that tenon looks to be a good .0175" thicker than on the left side of the tenon....better check your azimuth again...


Nice looking work...
That kit should be a big seller. The issue I've always had with threaded inserts is that they always expect you to tap them with the inserts themselves. That makes no sense to me...

_________________
"I want to know what kind of pickups Vince Gill uses in his Tele, because if I had those, as good of a player as I am, I'm sure I could make it sound like that.
Only badly."

Put me on ya list John, I am certain these insert kits will carry the usual Watkins hallmarks of quality and attention to detail.

Cheers

Kim

A couple of people mentioned the use of "hanger bolts". That sounds familiar, but I swear that I am drawing a total blank as to what they are.

For the record, I have been using the knock down hardware that Cumpiano recommends with the MT joint. I would like to "simplify" and eliminate the MT joint and just do the butt joint.

Donovan

My understanding of a hanger bolt is a bolt with wood screw threads on one end which would be screwed into the tenon with a bolt thread on the other end to allow the neck to be bolted through the neck block. The neck included in the Martin kit I got a few years ago had this as did the precarved neck I got from, I believe, Stew-Mac.

Steve
I would use the Cumpiano method. It's what I use now and I love it. If the split in your neck is really bad I would scrap it. Here is a link to some nice brass bolts and cross dowels that are perfect for the Cumpiano neck joint.
Neck Joint Hardware

Here's a hanger bolt:



-Mark

_________________
Pullman, WA

The more I know, the more I know I don't know.

trippguitars.com
OR
Find me on Facebook