Official Luthiers Forum!

For anyone who doesn't know, I've been working with a Nicaraguan luthier for the last while on some steel string guitars.

He's finishing the first batch but had a neck crack develop on one of the necks. I believe he just shaved the profile too low on it but we're both worried that the other necks might have a problem. So several questions for those of you who use hot rods or other dual action truss rods.

Forgive my ignorance if everything I'm asking should be obvious.


1. Do you place your access at the headstock or inside the body? Does it matter with these truss rods any more or any less than with any other type of rod?

2. What's your typical neck thickness at the nut if you use headstock access?

3. In general, after cutting the channel, what is the minimum amount of neck material underneath that can be considered safe?

4. To allow for more neck strength without an overly large neck profile, would it be possible to "cheat" a bit by routing a 1/16" or 1/8" slot in the underside of the fretboard? Seems like the fretboard's stronger than the neck material in most cases, so this seemed like a good idea to both of us but I haven't seen it done...so I assume there's a good reason not to.

I would greatly appreciate replies to any or all of the above questions. Some decisions have to be made in the next day or two so sooner is better than later!

Thanks,
Andrew Wright
Managua, Nicaragua

You can access the truss rod from either the headstock or the soundhole
I like a clean headsock so I always use soundhole access.
My neck thickness at the nut is around 21 to 22 mm (including fretboard)

For more neck strength, I use carbon fiber rods now. I use 1/4 x 1/4 from
Jim Watts. (Los Alamos Composites...sponsor)
You can even route your carbon fiber channel into the headstock for more
strength

I would NOT route the underside of the fretboardazimmer138867.5809375

_________________
Andy Z.
http://www.lazydogguitars.com

Any rod will fit snugly if you make the cut right; I use HotRods on pretty much all my necks, and will continue to do so until I run out. Then I'll give Allied's a shot. Might get a few of those anyway because they allow for slightly thinner necks (by about 2mm or so, IIRC, relevant only for super-slim guitar necks for me)

You need at least 1/8" below the rod to keep things in the 'safe zone'. Depth at nut tends to be about 21-22 mm, including fingerboard (board= 6mm, truss rod = 11mm, 3-4mm below that as safety). I also use dual CF in all my necks (pair of 1/8" x 3/8" rectangular rods)Mattia Valente38868.1944212963

   I have my truss rods made to my specs by a shop in Germany that I've dealt with for nearly 20 years. They are made from a strong but flexible chromoly rod imbedded in an aircraft aluminum channel. The channel disburses the pressure of the rod evenly along the bottom of the slot so that there is little issue woth the danger of popping through or cracking the neck.

   I always leave at least .100" between the bottom of the slot and the back of the neck profile. A low profile neck is more likely to create fatigue issues fr the player and can be as uncomfortable one that is too big so a comfortable size in the middle needs to be sought after.

   The Hot Rod is a great truss rod as is the LMI two way rod, but I've gotten great results with no rod failure and have more than 1000 made and on hand so I'll be set for while.

   I use carbon fiber in necks that show the possibility of being a bit more flexible or mae from woods that don't have the inherent strength of a quarter sawn Mahogany piece or lamonated neck.

Regards,
Kevi Gallagher/Omega Guitars