Truss adjustments

[dnf777]

This might get moved, but I’ll start here because its something most players, not just builders do, and a working kmowledge is a good thing.

Seems that “two-way truss” is a selling point with many makers, but how many of you have ever had to adjust more relief into a neck? (Other than un-doing someone elses over tightening). Sure, I loosened a few rods, but not to the point of adding torque to bow the neck. Almost always the string tension takes care of that. (If anyone’s interested feel free to make this a poll—Im too luddite)

I ask out of curiosity, and Ive seen two guitars ruined recently by ill-advised truss adjustments, and one was a two-way that was cranked counter-clockwise until the fretboard cracked.

[hermithollow]

A double acting truss rod is cheap insurance for poorly selected and seasoned wood being used to make a guitar neck. Back bow does happen - more frequently in lightly strung electric guitars, but also in some acoustics. As more instruments are produced the harder it is to find properly seasoned wood - the time from tree to finished guitar becomes less. 30 years ago you never heard of people worrying about humidity control. In extremely dry conditions guitars did dry out and crack, but it was not that common.

[charles Tauber]

Originally Posted by hermithollow

A double acting truss rod is cheap insurance for poorly selected and seasoned wood being used to make a guitar neck.

It might be used that way, but isn't the driving force for many luthiers who use them.

I started using two-way rods a few years ago. They take up the same footprint and weight as a common single-acting rod. I see no reason NOT to use one.

...30 years ago you never heard of people worrying about humidity control. In extremely dry conditions guitars did dry out and crack, but it was not that common.

It was very common. Ask any veteran repair person. Look in any museum that has older instruments.

The first Martin guitar I owned in 1974 came with a section on humidity control included in the "Care and Feeding" guide that was included by Martin with the instrument. Concern over humidity control is not something new to guitars, instruments or other fine articles made of wood. That guitar owners became aware that they could do something about cracking instruments is relatively more recent.

What was less common than now was using less stable flat-sawn wood, which now seems to be both common place and generally accepted practice. One of the consequences of using flat-sawn wood is that it is more susceptible to movement - and cracking - with changes in environment. One of the most striking examples of that is a well-known manufacturer using flat sawn black walnut when quarter sawn walnut is readily available. They made a choice: guitar owners are paying for it by increased concern over humidity and/or cracking.

[dnf777]

Charrles, Ill second that comment on flat sawn wood. I dont think its just cost, but also marketing some very beautiful grain patterns you dont see with QS wood. Black walnut and myrtle are stunning when flat sawn. They seem a little less susceptable to movement due to their mire random grain pattern. Im no expert by any stretch, just my slightly tempered opinion...

[charles Tauber]

Originally Posted by dnf777

I dont think its just cost, but also marketing some very beautiful grain patterns you dont see with QS wood.

That is certainly true, that quarter sawn wood, generally, has straight, "boring" grain. Exceptions include particular types of figure, such as the medullary rays in white oak, in lacewood/leopardwood and some figures in maple.

[Mr. Jelly]

I had to look up luddite.

[Brucebubs]

Originally Posted by Mr. Jelly

I had to look up luddite.

Are they still using my picture?

[Rudy4]

Originally Posted by Mr. Jelly

I had to look up luddite.

If you were a Luddite you wouldn't have been able to look it up.