Official Luthiers Forum!

Hot on the tail of the recent thread on this rod I just had a failure of the two way Blanchard designed Allied rod. This was one of a batch of 10 I bought in late 2011. It was tested as I always do by putting the butt end in a vise and cranking it both ways several times. It was installed with a filler strip.
The rod was installed on an archtop with carbon fiber reinforcement and worked well during neck leveling and all seemed OK until I was doing final setup just prior to going out. I usually need very little tension on the rod because of the neck reinforcement but during a little tweak there was a crack and the rod became non functional.

Because it's easy for me to do I took an X ray and saw the break at the distal weld. Since this was a headstock adjustable rod I drilled and tapped the allen nut and was able to get it about a third of the way out with a slaphammer, and the rest of the way with a visegrip. I thought maybe I could tap a new one in without removing the fretboard but it was too tight and I had to remove the board.


I made a surrogate neck as shown on the Allied web site and tested the remaining rods, two broke at the weld. One at each end. I talked to Allied and there may have been some bad rods out there. Apparently the new ones are much better. Bottom line, if you are using this rod be sure to test it aggressively as shown on the Allied website. If any question on the welds don't use it. I love the rod but I'll admit I'm a little scared to use another one. It really sucks to have to remove a fretboard on a newly finished guitar especially an archtop.

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It's not what you don't know that hurts you, it's what you do know that's wrong.

I'm just not going to bother. I bought a batch, and recently started to test them. I tested 3 and 2 of them broke, I'm afraid to use the one that didn't.

I'm using the Martin rods I just purchased instead.

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Old growth, shmold growth!

It sucks you guys re seeing failures, especially after the guitar is finished and done...

I roll with the solid 1/2" Tee-Bar...mostly to adhere to the KISS methodology.
But they won't break, that's fo sho.

Where do you get your t-bar stock?

This was a good archtop that was strung up, set up, sounded great and just needed a pickup before it went on the wall at the store. I noticed some slight increase in the relief and it was downhill from there. I think I'll put an LMI TRSD in it as I've used tons of those with no problems. With all the work it needs now including re-doing parts of the neck finish I'm not going to make much on this one. I've had better days but worse ones too. I'm getting some Martin rods from John Hall. Do you guys that use them feel that they are solid? Any installation issues?

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It's not what you don't know that hurts you, it's what you do know that's wrong.

Looks like the same way that mine broke. Taking the neck and fretboard off of a month old guitar is no fun, and knowing I've got a bunch of these out there that I'm responsible for should they break is no fun either. Ugh.

Anyone know how the Martin 2-way rods that John Hall sells compare to the Allied rods size-wise? I'm interested in going to those to.

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Steve Smith
"Music is what feelings sound like"

I'm only a beginner, but with all the quality-control problems with double action rods I would like to put in my vote for the KISS philosophy. I'm not a guitar maker, but I've done my share of design and played a few guitars along the way. With all due respect, I can't see the return on investment versus risk in putting something as complicated as a double action truss rod inside a guitar neck that's crafted correctly the first place.

These thoughts come to me for the second time in a short period. The first time was in reading one of Bill Cumpiano's blogs. He said that he stopped fabricating his own single action truss rods in favor of using the Stuart MacDonald double action one. His rationale was that his time is worth more than the double action truss rod's tendency to break-assuming far greater reliability than I've heard of in this discussion. In light of the preceding comments, threading some 3/16 Rod and checking to see that a new neck has positive relief comes in pretty cheap.

The rod seems to be about the same size, 1/4 in wide. The bottom of the rod is round the whole way across. The adjustment nut and a small portion behind it is 3/8th's inches wide and a hair bit deeper, but it's where the heel is and shouldn't affect the neck thickness any.

Assuming John Hall sells the same rod I purchased from Martin.

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Old growth, shmold growth!

Terence, I'm curious--could you post a close-up of the failed weld?

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David Malicky

So is Allied looking into these issues?

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Another day, another dollar.

I bought a half dozen Allied rods a couple years ago and after testing, no breaks, but two of them were real hard to turn. (threading issue?) They shipped out two new ones right away.

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Pat

I am too terrified to use either the LMI or Allied double action rod. There have been too many legitimate problems with these welds breaking for me to ever risk their use in one of my guitars. The problem is not with the design but the quality of the workers. I do love the design and Mark Blanchard sells these rods himself. He knows what he is doing and the welds are solid. They are more expensive but well worth it considering you no longer have to worry whether the truss rod will break.

I haven't heard of a LMI rod breaking, but maybe missed it. It's my understanding that the Allied (and Martin?) rods are imported but the LMI rods are made in the USA. The welds look alot better on the LMI rods, but they cost more.

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I didn't mean to say it, but I meant what I said.
http://www.brackettinstruments.com/

Thanks for the dimensions guys. So far I've been fortunate and have had no breaks in the Allied rods but given the Martin rod has a reputation for staying together and the size is about the same it's an easy decision for me.

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Steve Smith
"Music is what feelings sound like"

After initial set up it is the guitar tech who generally takes the fall for a broken rod. The manufacturer and guitar maker can shrug their shoulders and say "you must have over tightened it". As long as you don't do routine adjustments on your guitars, you're good!
I make my own single action rods. they don't offer as much adjustment and they can be broken, but they are cheap, and it doesn't sound like the double action rods are as reliable.

Truth be told, I've had one snap on me. It was in the neck, and I didn't bother to dig it out (the neck had another problem as well, so it was just easier to trash it). At the time, I thought I just turned it too much. Now I'm not so sure anymore.

I'm switching back to a traditional, Gibson style rod anyway so it doesn't matter for me, but it does make me scratch my head and wonder why these are all coming out of the woodwork now, and if Allied even knows it's potentially a problem. I'd never really heard of any problems before. I never reported mine because I assumed I torqued it too hard.

Here are some closeups of the welds. Not much material holding things together. After my failure I stressed the five I still have in a surrogate neck and two broke. This is one.







Here's an X ray of the one that broke. You can see the separation at the heel end. There was never a great deal of tension on this rod nor was it torqued very hard.



I don't think these little tack welds are up to the forces that happen in a guitar as well as the years of vibration that can cause repetitive stress and fatigue. My friends also tell me stainless is harder to weld. I have used the LMI TRSD rod for 12 years without incident. Those welds seem a lot more substantial. I will be looking at the Martin rod and the rod made by Mark Blanchard. I feel for Allied, they may have a real problem here.

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It's not what you don't know that hurts you, it's what you do know that's wrong.

Looking at the pictures, those welds look pretty pathetic. No penetration to speak of & they don't go the full length of the joint.
I have a dozen rods left from an order I made a couple of years ago & the welds look much better than the ones pictured here.
Before I install a rod, I always test it by winding it as far as possible in both directions.
While the threads are exposed, I smear a little Never Seize on the threads & work the rod 'till I'm sure the lube is coating the full length of the threads. Knock on wood, I've never had a problem with the new style (coarse thread / fine thread) rods.
It's a real drag that some folks are having troubles with these rods. I like them a lot, but will think twice before ordering them again.
Looks like John might need to stock up on those Martin rods... Might be a run on them soon!

After my experiences pre-testing Allied rods I feel it actually stresses and weakens the joint and pre-disposes it to breaking in the guitar.

Howeverr, no LMI rods I've ever tested have failed. They're also welded all the way around the rod. I think that makes a huge difference.

That being said, LMI rods are too expensive for me. I got 10 Martin rods for what it would have cost for 4 LMI rods.

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Old growth, shmold growth!

Trevor has a section in his book that shows how to make SA and DA truss rods. Not an endorsement (haven't used any in classical necks), but the design = ZERO breaks. No welds.

Just a though for those who use a lot. A few days to make a dozen that are guaranteed might be worth it.

Steve

I just wanted to say that the archtop looks great!

No...the shear load is more or less perfectly opposed when the rod is restrained inside the channel. Therefore, technically the weld should be stronger when the rod is isolated in the channel. When the rod is tested outside the channel the load works, to some extent, to peel the weld apart rather than to have the load applied in a perfect opposing force. In this way, a small stress crack can begin in the weld without fully breaking the weld, only later to have the weld break, after the rod in installed in a neck and pressure is applied.

I feel that a company that places the burden of testing on their customers, and then doesn't fully grasp the implication of that test....well...they aren't doing it right.

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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

Thanks for the interesting pics. Yep, very little penetration. They did at least use rod on this one, but still no bevel. The main problem I see is that the puddle is almost all on the rectangular bar, barely touching the threaded block. The failure is in the base metal of the block (the heat-affected zone, and also the melted base metal doesn't get the rod's de-oxidizers, so it's less ductile). If they consistently put the puddle on the bar, the welder is probably trying to avoid distorting the threads of the block, so they can save or minimize the usual step of re-tapping it (not a good bargain). It also looks like an entirely brittle failure -- I wonder if the block is made from a free-machining steel (1144, 12L14), which is nice for making threads but not for welding.

It's not hard to see why the Blanchard rods are silver soldered: far more surface area with little risk of distortion. They are pricey (brass and stainless), but silver soldering that small joint would not be expensive.

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David Malicky