Needed Truss-rod Length On Long Scale Or 36-fret Necks?

[Metallion]

How long does the Truss-rod have to be to give Best adjustment function and support?

For a 36-Fret (25.5") Guitar like Kramer's 36 F-1, or Washburn's EC 36?

Or even those 36-fret 12 string 35" scale Basses - Jerzy Drozd, Cirrus - whose Necks goes deep into the Body ?

How long are those Truss-Rods?

How does the use of 2 Truss-rods on Wider necks affect the needed TR-length?

Then what about Through-neck Guitars?

What is needed, or the Rule-of-Thumb?

Relative to Neck-Body Joint or end of Fretboard, specific measurements, etc...

Edited October 16, 2007 by Metallion

[Mickguard]

Well, some of this you're going to have to work out for yourself.

I built a 28-fret guitar, but it's a Gibson scale, so it works out to being about the same length as a 24 fret Fender scale. I used a standard dual-action truss rod, but I also added carbon fiber tubes that run from the nut to almost the end of the fretboard. The neck is a set-in bolt on --so there's a heel extension that goes deeper into the body. The neck meets the body at about the 19th fret, but is only fully 'enclosed' by the body starting from about the 25th fret -which is part of the reason I extended the tenon into the body.

Extending the fretboard to 36 frets would pretty much be the same thing --you'd have to cut away more of the body, of course, but only on one side, so the other side remains supported by plenty of body wood.

So I don't think there's any issue with using a standard truss rod, it all depends on the body design.

[Metallion]

I built a 28-fret guitar, but it's a Gibson scale, so it works out to being about the same length as a 24 fret Fender scale. I used a standard dual-action truss rod, but I also added carbon fiber tubes that run from the nut to almost the end of the fretboard.

A TUBE Rod?

Does that really give sufficient vertical [Perpendicular to fretboard] Support?