Official Luthiers Forum!

Next week after break, I start my wood shop project and I have decided to build an 0-17 style guitar. I don't really want to spend any money on this guitar, so I was wondering if one could use a hard wood such as purple heart for a truss rod. I know martin used ebony for a while, but ebony is not available in the school's shop. The hardest woods we have are some slivers of EIRW and some Purple heart which is what the fingerboard, bridge, heatplate, and binding will be made of. This guitar better get me an A lol

you'll have to buy something, tuners, bridgepins, fretweire to name a few. So why not just spend the $10-15 and get a truss rod? Although possible without one, why would you want to? It's pretty difficult to predict what the wood will do with tension on it. Seems like it'd make it really hard to setup the guitar.

you could make one for about 4 bucks .... single action, Gibson style.

_________________
Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

the simple truss rod like Tony is recommending works great. It is simple and reliable .

_________________
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

In their well respected book "Guitarmaking, Tradition and Technology" Cumpiano and Natelson show how to make a steel truss rod. This book is available through your public library and the materials are likely available in the shop department.
Also, since this procedure involves some metal fabrication you might even get some extra credit towards your grade!!
regards
pvg

I made one like that for a Les Paul that is 99% finished, but I keep putting off finishing it. The old Martins from the war era seem to be holding up well, so I want to use the wooden Truss rod. Will purple heart work?

I know, I have that book. I used that method to make the truss rod for acoustic number 2.

I think this is a worthwhile experiment. From what I've scanned in a few minutes, I think you're in luck: Purple Heart should work as well as any wood--perhaps better than ebony. Assuming that the wood you have is well seasoned, and that the guitar you build will be kept in a fairly humidity controlled environment (if not, the neck may be the least of your worries), then the property that matters most here is modulus of elasticity. You can do your own search to compare the MOE of Purple Heart to other woods. From what I saw, it looked pretty good.

You'll also want to maximize the depth of section of your reinforcement. A T-section would be ideal. Think, "More reinforcement, less neck". Try to make the reinforcement as deep in the center of the neck as you can. That said, fit-up is everything. A really stiff reinforcement in a sloppy channel will tell you more about the properties of your glue than your reinforcement. A tight fit at the ends the channel is particularly important.

Disclaimer: I'm a classical guy. I work on steel-strings, and I've restored early Martin steel-strings with no neck reinforcement whatsoever, but I have more experience with nylon strings. We reinforce necks, but we're dealing with one half the string tension, and have a much bigger neck cross-section to resist it.

But why not? Worst case is the neck warps under tension, and you learn something that no one here could have told you. You'll learn how to remove a fingerboard, and install a truss rod. And twenty years from now, when another beginner asks this question, you'll have a much better answer than we do. (Don't be surprised if he doesn't listen.)

Despite all our affected superior knowledge, we're all wondering what will really happen if you do this. We're the "flock?" of penguins, pushing the first
penguin into the ocean. If the leopard seal eats you,we'll all say we told you so. Me too: "I told you so".
--Eric

An important point here. We're not really talking about making a guitar. We are talking about the process of exploring and learning.

"Good decisions come from experience. Experience comes from bad decisions."

Ebony rods were used in conjunction with bar frets, which seriously stiffen the neck.
With regular fretwire you'll have to use substantial CF rods, which will cost more than a 2 way rod.

_________________
Laurent Brondel
West Paris, Maine - USA
http://www.laurentbrondel.com/

The worse that will happen with a non-adjustable neck is the frets will have to be removed, the fretboard planed to a back-bow, and refretted.

_________________
https://www.facebook.com/profile.php?id=100008907949110

I think there were some war era martins with T frets that had ebony too. Did they build them differently?

Some of these have needed neck work to correct warp. Some not. It is possible to do compression fretting with tang frets, and the knowledge of this was still available at Martin, since they had been using bar frets until 8 or so years earlier. Tricky business, though.

If you will be happy rebuilding a warped neck, go for it, because there is a very substantial chance you will.

_________________
Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

I guess I could use a real truss rod. The metal shop is right next door and the wood shop teacher is also the metal shop teacher, so maybe I can make one.

The best nonadjustable wood reinforcement I have used is the vee-shaped bar like Gibson used during WWII. IMHO, it is much better than the Martin ebony rectangular bar. Gibson used hard maple, but I like black locust, which is as stiff or stiffer than the stiffest tropical hardwoods.
The bar is a 90 degree vee, about 3/4" wide at the fingerboard surface. The groove is very easy to generate on a table saw, and clamping the bar in place is a cinch, with lots of gluing surface.
I have also made wooden adjustable truss rods, designed like the aluminum channel rods used by Martin and others. The channel was also made of black locust, with the same dimensions as the aluminum channel. The rod is 3/16" steel, with 10/32 threads on the adjustment end. The advantage over the bare Gibson style rod is that the rod is compressing a hard wood, instead of soft mahogany.

_________________
John

For our student guitars, we've had good results using a solid 1/4" x 3/8" steel bar, glued in with CA. If the fretboard surface is prepared flat, it will bow under string tension to give a relief of about 1/64". It makes for a fairly heavy neck, though. A 1/8" x 1/2" bar (or aluminum) might be better for a small body if it will fit your neck cross-section... less torsion stability, but adjustable rods don't have that anyway.

We used to make necks with no truss rod... we found a back bow of about 1/32" gave a relief of about 1/64" under string tension (solid poplar neck, no fretboard, minimal radiusing, extra light strings). These have been more stable than I expected (4-5 years now), but I'm not counting on that for much longer.

_________________
David Malicky

I've built quite a few guitars with static steel bar truss rods (usually solid, 1/4" square, epoxied in a tight cavity) and never had one yet (in over 10 years) be anything but dead flat. I did have one back bow slightly when it was fretted but that was easily taken out during the set-up and it's been stable for 8+ years.

Still, an adjustable rod is A: easy to make and B: cheap to buy. Not much reason not to.

It all depends on how well you know the neck wood.

If you are going to use the purpleheart like a truss rod, why not make a laminated neck with the purpleheart as the center section? Likely to make a more stable neck overall and just as easy or easier to construct. Of course, then you'll have a "striped" neck, which may not be what you are looking for.

_________________
Chuck Kish

How far we get from the OP… Brian wants to build a 0-17 facsimile with a wooden rod instead of an adjusting rod, he doesn't seem to want to use bar frets, which would seem to me the most logical vintage choice.
So far, apart from using an adjusting rod, John's suggestion of using a Gibson style v-shaped sounds the absolute best to me.
If I was to do that, I would choose a chunky V neck profile, around 1" at the 1st fret.

_________________
Laurent Brondel
West Paris, Maine - USA
http://www.laurentbrondel.com/

Hi,

This is a response to John Arnold's post. Thanks for the explanation of the Gibson neck reinforcement. I took this photo of a 1943 Gibson L-00' peg head at a guitar shop in Las Vegas. I was intrigued by the blonde triangle on the peghead, and I don't believe it had a peg head veneer. Now I know that it was more than a decorative inlay! Although this old gal looked like it had turned the odometer over a few times, the neck was still in pretty good shape.

_________________
A world without music would Bb.