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I would like opinions on neck reinforcement for a Martin style size 5 mahogany neck.
What does/did Martin do in the size 5? http://www.vintagemartin.com/necks.html indicates that steel reinforcement was never used on the size 5.
I don't know if that means they used ebony reinforcement or no reinforcement.
Is it necessary on such a short neck?
The scale length is around 21", so ebony, or carbon fiber reinforcement would only need to be 9-10".
My current plan is 2 strips of carbon fiber, 1/8" thick and 3/8" tall, placed 1/4" apart down the center.
I have some ebony, but I'm not sure that adds much stiffness.

yes an adjustable truss rod is what martin uses

_________________
John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

Yep, I put a truss rod in the one I made. Just makes sense.

_________________
Steve Smith
"Music is what feelings sound like"

Where did you find a truss rod that short? 2-way adjustable?

I just found a short one on Bitteroot's website. I ordered some of those.

I had it made to length by Blanchard. He makes good truss rods.


Steve

_________________
Steve Smith
"Music is what feelings sound like"

Give Me Truss Rod Or Give Me Death


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This just made my day, thanks Josh. My work is done here, they are accepting the value of truss rods, hallelujah!!!!

PS: I agree with Steve the Blanchard rods are excellent, I've used over 4 dozen of them and never had a single failure.

Wanted to add that doing exactly what Martin did construction wise on a vintage instrument pre-modern-steel-string is not advisable unless you are also keen to use the strings and tension levels of the day too. This can be done as well but not reinforcing the neck for modern strings may be problematic if the instruction manual... and person who knows what this guitar needs is not present and it's serviced or restrung.

All of the Greenridge Size 5 guitars (7? 8?...several student Size 5's as well) and - I am about 85% certain that - the guitar-shaped octave mandolins used a Size 5 truss-rod sourced from Martin. These truss-rods were about 1-1/4" shorter than the current Martin 12 fret rod, and worked quite well in terms of accommodating both the G-G tuning used with light gauge strings and E-E tuning when strung with medium gauge (as well as high-strung/Nashville). Should Martin no longer have the Size 5 truss rod available, an option exists to use a 12 fret rod with some length removed and the nut end rewelded/re-wrapped.

The boys were rewelding a rod for a custom job (conversion of an Artcore archtop to a shorter-necked Greek instrument) when I was last over for a custom project, and the post-weld check appeared to demonstrate plenty of strength and ability to generate relief. The shrink wrap used by Martin is very thin, and it can be difficult to source. The option is to use slightly thicker wrap and mill the channel slightly deeper/wider.

I echo Mr. Breakstone's comments - expecting something like an 0-18K neck conversion to T-frets without neck reinforcement to show the same stiffness and stability as the original flush-ground bar fretted neck is unrealistic with modern, higher tension strings. At Greenridge, we used dual 1/8" x 1/2" carbon fiber uni-directional rods set on edge, the shallower-depth, later-spec T-bars (quite heavy), and in one case, the current Martin 12 fret dual action rod (the guitar was essentially a neck block, so no loss of value or real appearance change with modern truss rod). The boys were of the opinion that adding an ebony neck reinforcement and compression fretting did not offer the stability of either bar frets or CF/T-bar/adjustable truss rods where modern, steel-core or higher-tension silk and steel strings were to be used.

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A constellation only takes shape when one maps the whole.
- Beth Brower

Another possibility is using a home made single action rod which can be installed to provide some (limited) double action adjustability, and will be lighter than most double action rods.

Does anyone know a source for the Martin size 5 truss rod?
I will evaluate the Bitteroot rod when I get it. Anyone have any experience with those?
I am also considering ordering the Blanchard rod. I have to figure out the exact length that I need.

Thanks for all the replies

The Bitterroot truss rods that are meant to be like the Martin two way rods (shrink wrapped, the adjusting nut is inside a round metal housing) are good quality, comparable to the Martins. There are a few small differences, but they aren’t shortcomings. I can’t speak to their other models.

Right. The Martin rods like you describe are the ones I use on my longer scale guitars. Bitteroot offers that style in the longer scales, but not in the 10 1/2" rod.
Thanks for the info.
James

Blanchard will make a rod whatever length you need. They are more expensive but worth it.