Martin D28 Guitar Non adjustable truss rod dilemma- Part one

118668-179fc998db725556aa9ce1d9966d7a82I have been working on a circa ’78 Martin D28 dreadnought style  guitar.  The guitar has a non-adjustable truss rod.  This is not an old or new situation since Martin Guitar continues to manufacture both non-adjustable and adjustable truss rods in the necks of their guitars.  This is however a very contentious and controversial little piece of equipment!  You will hear many comments and statements about the use of or lack of an adjustable truss rod.  Many have no real factual basis with the workings of the truss rod.

The truss rod is routed into a cavity in the neck below the finger board.  In a guitar with a non-adjustable truss rod, a solid or sometimes “t”  shaped piece of steel is used with no access to the rod.  An adjustable truss rod has an access routing, either at the peg head just above the nut or a hollowed routing at the other end of the neck, which is accessible through the sound hole. What’s it do?  Well, two different rods, and two different theories.The guitar neck is always under a good deal of pressure from six steel strings attached from the top of its neck to the bridge on the body of the guitar. A guitar neck without any truss rod reinforcing will have a hard time not to bend under that pressure and cause relief in he neck. Relief is a term used to describe the concave dip which that tension creates when the neck is no longer flat.

Here’s the controversial part.  Just about every guitar that I have played, repaired or purchased in the last 40 years has had an adjustable truss rod.  That alone should tell you something! The fact that the neck is always wood, be it maple, mahogany or any other species, wood is organic by nature, it will always be at the mercy of Mother Nature!  Extremes of heat, cold, low or high humidity effects wood, period.   So how does the truss rod help combat the stress of steel strings and a not so perfect Mother Nature?  Tune into my next post…….to be continued….


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