Necks without truss rods

#21
ardgedee said:
A few companies were making basses without truss rods in the 60s. They were mostly the low-end ones. It's not hard to find stories about Tiescos unplayable because the action's half an inch off the neck at the 12th fret...

In the 80s, some luthiers were building carbon fiber necks without truss rods (Steinberger, Modulus, Status...). This time it wasn't about being cheap, it was because they were confident their necks would never move under the loads presented by bass strings.

Every one of the '80s pioneers of carbon fiber use adjustable truss rods in their current products, and there are probably good reasons why. But they've proved that a trussrod-less neck is feasible (plenty of examples still being played 40 years later), even if it's not commercially viable, so this got me wondering...

How would you build a neck without an adjustable truss rod? How do you ensure the neck wouldn't move, without making it chunkier? (using a lot of carbon fiber is one answer, but are there others?) How would you add relief to the fingerboard when you can't just sand it straight and let the interaction of string tension and truss rod set the action? How do you even anticipate how much relief to add? How would you ensure the string paths on a fretless are properly leveled when you have to account for relief as well? Are there other complications I'm missing?
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Everything you ask could be figured out for these non-truss rod equipped basses just like Martin guitar luthiers figured out all the answers to all your questions (except the fretless question) by working on non-adjustable truss rod Martin acoustic guitars for about 80 years.

Martin eventually gave in and went with adjustable truss rods, primarily because there aren’t enough luthiers that can do a neck reset or re-fret job and get the guitar setup exactly the way players want their guitars.

There are a few rare exceptions, like Kenny Smith, who can absolutely kill playing acoustic guitar AND does all his own luthier work.

Some of the tricks to get truss-rod-free Martin acoustics playing well include; installing oversized tang frets (to introduce neck flatness or back bow), pre-loading the (non-adjustable) neck bracing rods, making thinner bridges with deeper saddle slots, and replacing top bracing. A few of these tricks wouldn’t work on electric bass, but a couple would. I figure the reason the bass builders started using adjustable truss rods was for the same reason Martin did; so the instruments could be fine-tuned for almost any player instead of there being unpredictable setups that cost a fortune in time & $$ to do a second or third time.
 
#23
No truss rod in the Vigier. It never moves and it’s always dead on no matter the string set. Its a phenom and an absolutely killer axe.

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#25
ardgedee said:
A few companies were making basses without truss rods in the 60s. They were mostly the low-end ones. It's not hard to find stories about Tiescos unplayable because the action's half an inch off the neck at the 12th fret...

In the 80s, some luthiers were building carbon fiber necks without truss rods (Steinberger, Modulus, Status...). This time it wasn't about being cheap, it was because they were confident their necks would never move under the loads presented by bass strings.

Every one of the '80s pioneers of carbon fiber use adjustable truss rods in their current products, and there are probably good reasons why. But they've proved that a trussrod-less neck is feasible (plenty of examples still being played 40 years later), even if it's not commercially viable, so this got me wondering...

How would you build a neck without an adjustable truss rod? How do you ensure the neck wouldn't move, without making it chunkier? (using a lot of carbon fiber is one answer, but are there others?) How would you add relief to the fingerboard when you can't just sand it straight and let the interaction of string tension and truss rod set the action? How do you even anticipate how much relief to add? How would you ensure the string paths on a fretless are properly leveled when you have to account for relief as well? Are there other complications I'm missing?
Click to expand...

I tried a Modulus once where the neck was completely destroyed, horrifically warped and the strings were an inch off the fingerboard, and there was no way to fix it. Truss rods are a part of the instrument, I see no point in trying to eliminate them.
 
#29
petermwright said:
Interesting topic. I’ve never owned a bass with a carbon fibre neck, but am intrigued by the idea of a neck that doesn’t move with the seasons, and have wondered how much relief you get with a carbon fibre neck, and if you can adjust it.
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I owned a carbon fiber necked Modulus with no truss rod. That thing was 20 years old and the neck was straight as an arrow.
 
#35
petermwright said:
So are they designed to have no relief?
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Just eyeing the string shadow, fairly dead straight or barely any relief. Played great!

Zooberwerx said:
I had an early Zon Sonus that met that description...didn't keep it for too long.
Riis
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There was nothing wrong with my bass because the neck was straight. Ric, eg, recommends little to no relief for a best case set up and my Ric’s do work best that way.
 
#36
Bruce Johnson said:
You can build a neck without a truss rod, if you really want to. You'd probably want to build it fairly stiff, adding some internal stiffeners like aluminum plates or carbon fiber TOW backstraps. And the process for surfacing the fingerboard and leveling the frets gets more complicated. You have to measure and/or guess how much the neck is going to flex under the tuning and strings that you intend to use on it. Then figure some way to preload the neck to something a little less than that. Surface or level it. Then string it up and hope it comes out to the right amount of relief. A lot of guesswork and trial and error.

Or, you carve the surface into the curved relief shape, guessing how much the neck will bend when you apply the string load. Planing a curved shape, while keeping the string paths true; no lumps or dips. It's tricky.
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It crossed my mind this afternoon that there's a way to separate the two steps of adding relief to the neck and finishing the fret/fingerboard: On a neck without the fretboard/fingerboard attached, add relief to the surface of the top of the neck. Then prepare the fretboard/fingerboard on a flat surface -- leveling frets or faceting the board surface as necessary -- and then once finished, glued them together, bending the fretboard to the neck's surface.

Of course this assumes the neck is either as inflexible as granite or the builder accounted for the board's desire to straighten out when calculating the forces necessary to get the right shape after all is said and done. So, maybe a little easier, but still not actually easy.
 
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#37
Flying B said:
I wonder what's the advantage of not having a truss rod? Aside from maybe the weight saving gain? I suppose if you live somewhere with wildly varying levels of humidity/ temperature and you're forever having to adjust it that could get annoying. I hardly ever touch mine.
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OP's observation about the rod-less wonders of the sixties is spot on. Most were either budget or next tier up brands. And to compensate for the lack of truss rods the necks were chunky. I've got multiple Multivox Marvel and Supro violin basses, and there is only one neck with a truss rod in the entire lot. And yes, there is neck bow. But these basses also have no dead spots. That's the gain.

And the Marvels truly are one-piece necks: no truss rods and no separate fingerboards either.

I wonder, might a solution for OP's quandary be necks made from quarter-sawn wood?
 
#40
Tim Skaggs said:
Everything you ask could be figured out for these non-truss rod equipped basses just like Martin guitar luthiers figured out all the answers to all your questions (except the fretless question) by working on non-adjustable truss rod Martin acoustic guitars for about 80 years.

Martin eventually gave in and went with adjustable truss rods, primarily because there aren’t enough luthiers that can do a neck reset or re-fret job and get the guitar setup exactly the way players want their guitars.

There are a few rare exceptions, like Kenny Smith, who can absolutely kill playing acoustic guitar AND does all his own luthier work.

Some of the tricks to get truss-rod-free Martin acoustics playing well include; installing oversized tang frets (to introduce neck flatness or back bow), pre-loading the (non-adjustable) neck bracing rods, making thinner bridges with deeper saddle slots, and replacing top bracing. A few of these tricks wouldn’t work on electric bass, but a couple would. I figure the reason the bass builders started using adjustable truss rods was for the same reason Martin did; so the instruments could be fine-tuned for almost any player instead of there being unpredictable setups that cost a fortune in time & $$ to do a second or third time.
Click to expand...

You left out Martin's suggested setup solution from the 70's.

In the early 70's I was considering purchasing a new Martin so I went in to our local dealer to check them out. Each new Martin had a tag attached to a tuner that had "instructions" for setting neck relief. To paraphrase "If the neck develops excessive forward bow the player should install lighter strings. If the neck is too flat without enough bow to help achieve proper buzz-free action then the player should install heavier strings".

No kidding, that was 100% real.
 
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