Truss rod length in a 24-fret

[NickInMesa]

I am a bit concerned because if a bass scale is 34", this means the 24th fret is at 25.5".

The longest truss rod I have found so far is 24"

So either the truss rod in my RBX stops 1.5" before the nut, or Mr Yamaha has some custom-made truss rods.

Also, on a side not, what is the longest truss-rod made out there?

Just to know if a 30-fret bass is possible

[vbasscustom]

yeah, the longest production ones that ive seen are only 24", your fine with that. and you should be able to make 30 fretter, but your gonnah vae to maket he bottom frets in the body, extend the board out over the body and make them there, you could make a deeper cutaway

[NickInMesa]

I am kidding about the 30 frets but am I right that the truss rod will not go all the way?

Do they trust the top to bow properly and follow the rest due to the natural resistance of the wood? One could expect extra strength on the wood at that point. 1.5-inch is not too long but Yammies have small necks.

[NickInMesa]

Another question came to my mind: what about neck-thru-bodies: is the truss rod inserted only in the neck section? Had anybody create an NTB with a truss rod going through the table as well?

I know, some dumb questions to some, but I'm just curious!

Thanks

[mikeyswood]

A truss rod is there to compensate for the bow in the weaker section of a neck. A single cut bass with the horn connecting at the 12th fret will only need about a 15" rod.

It does not need to run the entire length under the strings. If you use a thick and strong neck you will not even need a rod.

To answer your question: 24" is fine.

[NickInMesa]

Thanks, Mikey.

The weakest section should be at the tip, am I right?

In this case wouldn't it make more sense to place the truss adjustment under the nut?

Thanks

[mikeyswood]

...kinda

The neck is forming an arc under tension. With proper truss adjustment you are getting the arc small enough to set the strings to a tangent of that arc in what appears to be a straight line.

Where ever you straighten the arc does not matter.

[NickInMesa]

Originally Posted by phustercluck

The truss rod should be as long as the truss is. If the truss is longer than the truss rod, then the truss rod will not reach the full length of the truss and the truss will be undersuported (not held) at each terminal. Therefore it is very importatnt that you be sure that your truss rod is long enouth so to reach each ind of the trusses. So long as you do it, you will be fine.

I understand. How does Yamaha do it, then? Do they have a custom truss rod done for them?

If yes, one would expect to find it on the market...

[mikeyswood]

Originally Posted by phustercluck

The truss rod should be as long as the truss is. If the truss is longer than the truss rod, then the truss rod will not reach the full length of the truss and the truss will be undersuported (not held) at each terminal. Therefore it is very importatnt that you be sure that your truss rod is long enouth so to reach each ind of the trusses. So long as you do it, you will be fine.

That is some Grade A gibberish.

From an engineering point the truss will begin when the thickness of the material can no longer support the stress put upon it. Maple will be different than Mahogany and Balsa is right out.

Your truss rod should run from where the neck leaves the body to the nut in a neck through. For a bolt on you can shim under the neck to get the action close enough.

[NickInMesa]

Originally Posted by mikeyswood

That is some Grade A gibberish.

From an engineering point the truss will begin when the thickness of the material can no longer support the stress put upon it. Maple will be different than Mahogany and Balsa is right out.

Your truss rod should run from where the neck leaves the body to the nut in a neck through. For a bolt on you can shim under the neck to get the action close enough.

But what I don't understand here is that the adjusting nut is right under the 24th fret.

Again, with a 24-inch standard truss rod, the rod will run from a little before the 1st fret. If we count the half inch of neck above the nut, it's short of 2 inches.

Which means they have to use a 26-inch truss rod, or leave 2 inches of neck without rod support, use some sort of device.

I know how Yamaha builds motorcycles, I took some of these engines apart and they always are well machined, but they are not overly innovative. They usually let the Europeans take risks and then learned from the lessons of others.

If they apply the same philosophy to bass guitars, I don't really think Yamaha will do something new there either, unless it's a totally different philosophy.

[burlboy]

I think Pedulla start their rod at the 2nd or 3rd fret and exit at the heel

[mikeyswood]

Originally Posted by NickInMesa

But what I don't understand here is that the adjusting nut is right under the 24th fret.

Again, with a 24-inch standard truss rod, the rod will run from a little before the 1st fret. If we count the half inch of neck above the nut, it's short of 2 inches.

Which means they have to use a 26-inch truss rod, or leave 2 inches of neck without rod support, use some sort of device.

Let the geometry work for you. A 24" truss rod will be fine for a 24 fret neck. The arc that occurs on the unsupported ~2" will be insignificant.

I prefer my trusses to start at the nut since I build neck throughs and the last few inches have the thickness of the heel transition.

[vbasscustom]

yeah, really, any nech has a heel, that is supported by something, in a bolt on or set neck, the truss rod doesnt need to be in that area because it is either bolted or glued to the body