Martin Guitar Necks

Sizes, Shapes, and Reinforcements

Ebony and Steel Truss Rods

The following information taken from Mike Longworth’s transcription of the Martin Shop Orders indicates which wartime Martins were built with Ebony truss rods
in place of the usual steel rods due to wartime restrictions on the use of steel.  

I’m presenting this here as a general guideline since Mike’s work, while tremendously helpful, did include quite a few errors.  The contemporaneous Shop Orders
may include errors as well.  So the guitars themselves should always take precedence, and info from the logs should be verified by looking at the guitars. 
Fortunately, guitars are our friends and never lie!  Put a magnet to you guitar’s neck, and it will tell you immediately if it has a steel truss rod buried inside or not!

Observation, in fact, was the basis of Longworth’s ongoing work.  What most folks mistake for the “Martin logs” is actually Mike’s transcription of the logs used as a starting
point for adding his notes from observation of the guitars he inspected in person.  He was always looking to verify and add to what he saw in the original shop orders

While most guitar listings from the wartime period are followed by an “(E)” or an “(S)” to indicate “Ebony" or “Steel", quite a few are not.  In some cases where we have a
long string of “(E)”’s with a few in between with none, It seems fair to say that the lack of an “(E)” would indicate the opposite, but we can’t know for sure. 
I’ve indicated here with an * which of these are not noted but may be reasonably presumed from context.  

Please let us know which of your guitars can help clarify the ambiguous listings.

The “Bar frets” wedged into the fingerboard on Martin guitars built before 1934 have the additional benefit of keeping the neck straight.  So all Martins built before
August 9, 1934 57305 have ebony neck reinforcements or no reinforcement at all.  

When Martin switched to T frets, a steel T bar was added to the neck’s interior to help keep the necks straight.

Tenors, classical guitars, and size 5 Martins never had steel truss rods.  

Guitars with the following serial numbers should have ebony neck reinforcements due to wartime restrictions:



#80863 - 83107
81118-29*  (*not noted - presumed S)


All have ebony truss rods. 


All have ebony truss rods. 



#90150 - 90360




91567-91 “T”

#91623 - 92495
91960-71 (partial - 4 with E, 8 with S)



#93233 - 93623**  (**not noted - presumed E)


Jan 1 - May 3 
# 93624-95295 -- not noted - presumed S
#95144-68 (E)

#95296 - 97909 (E)


All have steel truss rods
101207** (lefty)
103082*   (lefty)

Neck Sizes and Shapes

So what makes a neck feel thin or fat?

I have lots of Martin guitars, from 1834 to the 1960's, with lots of neck sizes.  And I have some that I'm really in love with, such as my early January, 1930 OM-28

which has an unusually wide 1 13/16" wide neck which feels extremely shallow, and Gibson necks from c. 1930 that have a similar feel. 

While most folks are fans of the 1 3/4" necks from the '30's, and I'm used to wide necks - I grew up with a 12 fret 1964 00-21NY with a big neck, and can even

handle my 2 1/8" Roy Smeck - the 1 3'4" doesn't feel as comfortable in my hand, and the wartime necks feel great to me.  Some folks consider the Gibson AJ to be the

Holy Grail.  I'm allergic to it's neck.  If I don't get it out of my hand immediately, I'm in pain with cramped hands.

When I started to catalog the details of my guitars, I learned something interesting.  Wartime Martin necks that felt "fat" to me, actually measured exactly as deep

as necks that felt much thinner, front to back.  This is when I learned that it's all about the "Shoulders".  While some necks have an obvious "V" and others are round, there are

many gradients in between.  And it's the contour of the shoulder- the part of the neck that's missing in a "V", not the depth of the dead center

back of the neck, that usually determines how thin or fat a neck feels. 

The Move to Thinner Necks

Martin phased in steel strings between 1922 and 1926.  They apparently didn't see any need at all at the time to change the neck size, either to accommodate steel strings,
or because steel strings allowed them to do so.  

The neck was slimmed, however, in 1929, from 1 7/8" to 1 13/16", for Perry Bechtel's OM "prototype".  Evidently, this was not considered enough, or they simply realized
they could go further, so the production guitars were tweaked further to 1 3/4".  A 1/8" change from 1 7/8" to 1 3/4" is considerable, and I do believe this decision to
have been clearly influenced by banjo players.  The 14 fret neck was requested by Al Esposito for the 4 string Carl Fisher tenor guitar, which we know was fashioned to
attract banjo players as the banjo waned in popularity.  Even in the months before Fisher, the tenor guitar was introduced by Martin for banjo players with a 1 1/4" neck, a tiny
neck compared to any previous Martin.  I believe that this idea is reinforced by the fact that Martin continued to produce the 12 fret with the exact same 1 7/8" neck width, with
no changes at all after nearly a century, allowing Martin to offer the traditional wide neck to traditional players, and the new thinner neck to these newer converts to the guitar.

Martin has seldom made changes on their own accord, but almost always due to customer demand, either by the market in general, or more often in response to specific requests. 
In 1939, the market spoke again, as musical styles changed from those based on traditional right hand finger style playing, along with a more intricate left hand technique, to
playing with a "plectrum", often with simple strumming and "cowboy chords", as a simple accompaniment to singing.  So Martin responded in 1939 with a relatively minor 1/16"
tweak from 1 3/4" to 1 11/16".  As tastes and musical styles and techniques have changed once again with the times, Martin has more recently tweaked their product line back
in the direction of 1 3/4" necks.  

On the left is Martin's first unsuccessful attempt at a longer neck on a tenor guitar, with no doubt designed for banjo players.

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