Official Luthiers Forum!

I was approached by a member here who wanted to buy a handful of these...and I hope when I turned him down I told him the true reason I didn't do it. I don't want to be in business again. Been there and I'm retired..no longer accountable. I can't be...I was watching my wife lose her sanity (she's in a home now at 61 years old). The emotional crap that goes with all that is stifling creatively. I basically shut down everything related to any creative activity and managed her decline.

But after 9 moths of her living somewhere else I'm coming out of that emotional morass... and beginning to rekindle old interests.

These were tested thoroughly though. I proved them to be consistent and reliable...I'm certain they ARE the the only rod of its kind on account of the molded composite threads and the 47 grams total weight. One of the more cool aspects of this design is that there is SMOOTH, dampened action when it comes to adjusting. Very small adjustments are easy and quite accurate.

I used these in my guitars exclusively...and then I eliminated the use of an adjustable truss rod altogether.

The molds were fairly complex affairs. Included is a pic of the measuring tool I had to make to compare the strength of these rods with the typical steel rod. These 47 gram rods came in consistently at 4/5th the strength of steel, welded rods.

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I read Emerson on the can. A foolish consistency is the hobgoblin of little minds...true...but a consistent reading of Emerson has its uses nevertheless.

StuMusic

If ever did this again I could add 22% more weight to gain 50% more strength....which would make these consistently stronger than steel rods by a fairly wide margin. Then, I wouldn't worry about people that build bad guitar necks and crank their truss rods to offset that.

In other words....I COULD make this rod something I never worried about. I can make good necks so the rod doesn't have to do much...but I didn't want to market this rod...because I'd have to discern how the builder was going to use it.

They take just under an hour to manufacture (this doesn't count idle time curing). It would be profitable (after redesign) to sell them for around $65. It's a market - I think.

I weighed every truss rod there is and remember 145 grams to be the average weight of steel rods. Can't remember all the weights but this one is 1/3rd the weight.

_________________
I read Emerson on the can. A foolish consistency is the hobgoblin of little minds...true...but a consistent reading of Emerson has its uses nevertheless.

StuMusic

I'd be interested for that kind of coin.

Now - the big question. What about twist? How can we correct that without using traditional heat pressing?

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"Act your age, not your shoe size" - Prince

Still...it's a meager market...considering that most builders won't get easily excited about anything that costs $30 or more.

I've seen some masterwork titanium rods that looked like they were made by NASA. I'd use those if I didn't use mine.

I'd say for $40 you are hitting on all cylinders with this stainless steel rod. This looks good on paper.

http://www.blanchardguitars.com/guitarp ... _rods.html

Twist? Take out the wood (propensity to twist) and replace it with things that are inert, stress free, and multiple times stronger than any wood. That problem is 100% solved. Now...does it sound good? You gotta make one and find out. That's ultimately the thing I feared the most...but the prototype sounded ACOUSTIC...due to the space in the neck and I really like the tone. ...and it's LOUD without an amp.

That hollowness adds a variable that I can control by experimenting with various core materials of varying densities.

_________________
I read Emerson on the can. A foolish consistency is the hobgoblin of little minds...true...but a consistent reading of Emerson has its uses nevertheless.

StuMusic

Hi Stuart,
I been mulling over embedding a honeycomb panel of carbon and nomex about about 1-3/8 wide (or so) x 1/4 thick just under and slightly into the fingerboard and into the neck shaft. Haven't done though as I'm afraid it might be too stiff and have a negative effect. I'd be interested in you thoughts.
Your truss rods look good btw.

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Jim Watts
http://jameswattsguitars.com

Are the nomex chambers hollow or filled with an expanded syntactic foam? Anyway...the range of what are are describing is pretty large...from cheap panels to full-on, engineered aerospace control...and everything in between. Burying a potential problem into my handiwork doesn't excite me initially. If you have a piece made to rigorous standards (I can't really know)...it's interesting...maybe...but I'd eliminate it from my thinking if I couldn't find data on your piece.

I think what you might be doing is holding something and looking for a purpose. Ask yourself what problem it solves. If you don't have a clean answer it ends up a waste in the end. Unless you make it and find out. Then you'll know.

You have to at least compare its compressibility to the wood it replaced.

_________________
I read Emerson on the can. A foolish consistency is the hobgoblin of little minds...true...but a consistent reading of Emerson has its uses nevertheless.

StuMusic

I've made a lot panels over the years for the aerospace industry, so it'd be a high quality panel with unitape prepreg skins.
No wet layup or gorilla glue involved.

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Jim Watts
http://jameswattsguitars.com

I really like this truss rod!

Thats really cool Stuart.

Sorry about your wife man

I totally agree with this, I'm not sure what if anything it brings to the table. There's a billion guitars out there that work just fine without it.
This is ultimately why I have done it yet.

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Jim Watts
http://jameswattsguitars.com

As resources dwindle and necks are made out of molded particle board with a thin Richlite veneer fretboard, a mass produced honeycomb with prepreg carbon fibre skins might be just the ticket to add back the stiffness the neck needs. Applause guitar neck on steroids. High Tech solutions often wind up on the low end of the market if scaling up can bring the cost down.

Thank you, it's a tough road to hoe. I'm glad to see the other side of it. My mom was the artist...a true blessing for me but....

My father blessed me with the ability to "plod" through life. You resign yourself to what's coming and you just keep plodding. You don't ever stop until you are stopped. Best gift I have. Plodding with resolve. My father.

_________________
I read Emerson on the can. A foolish consistency is the hobgoblin of little minds...true...but a consistent reading of Emerson has its uses nevertheless.

StuMusic

Hi Stuart,
I wondered where you went and now know you were dealing with some very challenging things - my condolences as well, that is such a difficult thing to watch happen to a loved one.

Regarding the truss-rod, I think it is brilliant and I would absolutely be willing to try one of these -- the Blanchard rod is great but adds a lot of weight. Some of this stuff is outside my wheel-house. I've heard carbon fiber can shear (as in the heads of bolts) -- otherwise, I might look into using carbon fiber bolts for my neck attachment.

Can you comment on the strength of carbon fiber in terms of shearing -- ie would a careless customer have a much easier time damaging this rod than say the Blanchard rod? Also, what do you think about using carbon fiber bolts in a guitar - are they strong enough? we aren't talking that much weight savings for the bolts but the truss-rod would definitely have an effect.

--
Simon

Back in the day I tested all the available truss rods and settled on the Blanchard rod for my creations. 54 - 55 guitars later and 16 years not a single issue or failure.

But IIRC my Blanchard rods were around 119 grams (check me on this I am trying to remember something from 16 years ago...) and that is significantly heavier than what Stuart has created here. I would have jumped at CF had they been available for not only weight/mass reduction but where that mass is our away from the body, not a good place for a guitar to be unbalanced because they dive it you take you hand off them.

Being in the repair business I know how much people depend on a decent, quality truss rod and also how often a double action rod saves the day on a dried out guitar.

These look great Stuart!!

My design was tested comparatively to steel rods. I made a jig that held a rod and then projected a laser across the shop onto a wall 60 feet away. I broke a dozen steel rods and marked the spot where they broke. Then I broken a dozen of mine. Mine broke at a distance of roughly 7/8 of the distance of the steel rods....but the loading is not linear. I figure my rods are 4/5th of the strength of the steel lines.

There is a VERY smooth turning action under load....infinitely smooth adjusting...so when it gets tight you know you're on the verge. Anyway...a neck made with reasonable craftmanship only need the truss rod to overcome string tension...which isn't much. Yes, these rods would be fine. I ise them in my guitars without compunction...but I start out with straight necks.

...and finally....I don't use adjustable truss rods anymore at all. All my necks are now rigid, reinforced and no adjustments are necessary.

I wouldn't use carbon fiber bolts if you don't have to. They don't have adequate tensile strength to make me feel good. I wouldn't use them unless the design absolutely required weight savings and the testing was finished and proven out.

_________________
I read Emerson on the can. A foolish consistency is the hobgoblin of little minds...true...but a consistent reading of Emerson has its uses nevertheless.

StuMusic

Thanks Stuart,
I'm away helping my brother move for the next week but will definitely get in contact with you about these t-rods.

Best Regards,
Simon

47 grams is amazing for a double acting truss rod. For those high end builders who value light weight necks, $65 would probably be acceptable. I hope that rod finds its way to market at some point.

Just to clarify the weight issue on the stainless rods that I make, a 13" rod (12 fret) weighs 96 grams and a 14 1/4" (14 fret) rod weighs 104 grams. I recently started making the backbone of the rod and the end blocks out of a single piece of stainless bar, thereby eliminating the silver brazing joints at each end of the rod. I'm also milling the backbone into a "T" shape to reduce weight.

I'm really happy to see various people giving truss rod design some serious attention. A truss rod is a VERY important piece of hardware in a guitar. Rods that are ineffective or fail in use are a real disaster !!

Mark

One thing I will add to this conversation in regards to how important truss rods are... I was using the Martin rods for a while then found them difficult to get and switched to the Bitterroot rods which are very Martin like. What I like about those rods is that you can design your neck such that the rod is removable. Even the very best of the very best has a failure rate. So if a rod fails and you can simply remove it and replace it that's good design imho.

The composite truss rod is super cool- I have certainly remembered it from when you first discussed it Stuart! I'm always impressed by your manufacturing methods, you are certainly approaching this from an angle most of the rest of us simply don't have the knowledge to imagine. And I'm very sorry to hear about your wife, my condolences.

I had the same desire (especially after you weren't selling yours )- a lightweight double action rod. I ended up making my own that have served me fairly well. I haven't done any proper tests, though, to measure how well it realistically stands up to the same style made from all steel. Informal tests, yes- and it seemed comparable, but not well thought out or repeatable. I'm using a titanium rod and an aluminum bar/block system, milled from solid as it appears Mark has moved towards as well. Steel for the threaded and hex broached parts, with a pin and 648 loctite connection (couldn't figure out how to get the silver braze in that tight spot with everything else around it.....). The back end is fixed in place so the rod does not (or shouldn't) spin in the cavity, just push and pull. I expect that the titanium stretching (or the threads distorting) is the weak point in this design but honestly I wouldn't know how to even make that comparison, i'm 100% not an engineer Weight is about 55-ish grams for a 14 fret rod, and the weight is off center, with the excess by the nut. I use it with the nut in the neck block and the headstock end of the neck is very light, which was my goal.

When I use them I am also embedding them within a carbon fiber U bar. The neck is nice and stiff, I have never actually needed to use the truss rod. but it is there!





More:
https://www.instagram.com/p/Bu4dg8EnRK2/
and threading the titanium with my antique thread chasing setup :
https://www.instagram.com/p/BsWjUg6nFBt/

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Burton
http://www.legeytinstruments.com
Brookline, MA.

When I get a lens for my camera (in the mail) I'll get some better pics of the detail of the two-way carbon rod and details some aspects of the parts.

I designed mine to require only a smooth, accurate .25" x .35" groove to hold it. I did a secondary molding process to achieve the carbon wraps on the ends to constrain it within those specs.

Wait a bit. I'll have detailed pics....if the lens is as good as they say.

_________________
I read Emerson on the can. A foolish consistency is the hobgoblin of little minds...true...but a consistent reading of Emerson has its uses nevertheless.

StuMusic

It wouldn't be too hard to compare the thread loading ability of the titanium if one knew the exact alloy. A lot of truss rods are made from simple 1080 steel...and some are made from unidentifiable alloys. The mechanical properties of the materials are all published. The property "sheer modulus" would basically cover the load on threads. You want to compare the other properties too...but sheer modulus is the first property for thread loading. Yield strength would be the next property to consider.

Basic, generic "titanium" Titanium Ti-6Al-4V (Grade 5), Annealed is about half the sheer strength of 1080 steel....so....I guess I'd worry when it comes to applying moderate torque.

I knew the necks that used your U -shaped idea would be savagely rigid...provided the fiber was super compacted at that thickness. After three custom molded carbon reinforcement shapes...I stopped thinking about adjustable truss rods.

I'll photo the cross sections of mine and make a new post later.

_________________
I read Emerson on the can. A foolish consistency is the hobgoblin of little minds...true...but a consistent reading of Emerson has its uses nevertheless.

StuMusic

Mine are almost 18" - I make only electrics - factoids.

You betcha on that single homogenous stainless bar. The fear. The fear. The fear of making something that breaks in the necks of high end guitars. How is the sheer modulus of your alloy compared to 1080 rolled steel?

_________________
I read Emerson on the can. A foolish consistency is the hobgoblin of little minds...true...but a consistent reading of Emerson has its uses nevertheless.

StuMusic

My truss rods are made from both 303 and 304 stainless. The backbone is 304. The round bar and the adjuster are 303. Both of these alloys have a higher shear modulus than 1080 steel, 77 GPa for stainless compared to 72 GPa for 1080.

These stainless alloys are also slightly less elastic than 1080, a property that I feel is important in truss rods.

A comparison of these alloys can be found here:
https://www.makeitfrom.com/compare/AISI ... rbon-Steel

Thanks Stuart- I am using grade 5, and looking through the charts it certainly doesn't seem to be as ideal a choice as pretty much any form of steel. I can _kind of_ understand those numbers- elasticity, elongation and deformation- Where I really lose it is trying to calculate what kind of force we are actually talking about inside the neck when the screw begins to turn. I can imagine some of the variables (or at least I think I can) but have no idea how to come up with a number. Titanium is more likely to deform than steel, and more stretchy, yes- but it still might work? Or could be designed in a way that could be made to work and still be lightweight?

I felt OK about it because others were making titanium rods (never the best rationalization), I didn't expect to really need it in my necks, and my initial "tests" seemed promising. But there's no long term data test under pressure. I need to find someone to help me see the whole picture.

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Burton
http://www.legeytinstruments.com
Brookline, MA.

The way to find the tension on a bolt or thread is to monitor torque of the bolt itself. Torque conversions are tricky because...how calibrated could a tiny torque wrench be? How many variables are there?

But if you have a good torque wrench meant for smaller loads....simply monitor torque on the wrench and convert using this chart.

https://goodyearrubberproducts.com/file ... Page46.pdf

For instance, 4 ft .lbs. of torque on a 1/4 -20 bolt will impart 810 lbs of tensile load on the thread/bolt. Lubricating the thread is critical for a good torque measurement. If that is anywhere the yield strength of your alloy you are in trouble probably.

_________________
I read Emerson on the can. A foolish consistency is the hobgoblin of little minds...true...but a consistent reading of Emerson has its uses nevertheless.

StuMusic