Official Luthiers Forum!

Does everyone use a hardwood spline over the truss rod prior to fret board installation? Sometimes it seems unnecessary to me. The truss rod I use (double acting) from Allied has a flat metal top to it. The footprint of pressure on the FB seems like it would be the same for either spline or rod itself. Am I missing something? I can see that you would have to be very precise with your depth without a spline, but you can also then leave more solid wood under the rod.

Please let me know what you do. Thanks.
Donovan

I don't use one, but I'm not all that opposed to one. I'm on #10 and 11 and haven't had any problems yet without it. I have heard of some folks using a tapered spline to leave more wood near the nut. Its my understanding, though, that this would necessitate a tapered truss rod channel.

-j.

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“If God dwells inside us like some people say, I sure hope He likes enchiladas, because that's what He's getting”
-jack handy

I do now but I didn't in the past and I use the new Allied rod too, before that I used the LMI rods which are dimensionally the same and weigh the same - 119 grams. But this is where the similarities end. The new style Allied rod is the best on the market IMHO. It also has a nicer fit and finish with no weld globs that have to be sanded off to get it to fit snugly into a 1/4" channel.

Mark Blanchard who designed the Allied rod, the new one, posted a while back on why we need to use the spline and it all made very good sense to me. So going forward I will be installing one.

I use the same rod, but I use spruce bracing stock for the spline...

j, a compression rod uses a tapered channel for this, but LMI and Allied style rods do not. The flat bar just gets pushed down more in the middle. At the ends it's supported by the nuts.

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Mike

"The Dude abides. I don't know about you but I take comfort in that. It's good knowin' he's out there. The Dude. Takin' 'er easy for all us sinners. Shoosh." The Stranger

Heshstoned, I couldn't find the thread you refer to here. Is it the truss rod from Allied Lutherie? It appears to be the exact same rod that LMI sells. Allied sells them for about six bucks cheaper than LMI. If it isn't the same rod you use, would you mind submitting a LiNk so we may observe the differences? Thank you my friend.

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"After forty-nine years of violin building, I have decided that the search for a varnish is similar to the fox hunt. The fun is in the hunt."
Jack Batts Maker and Repairer of Fine Violins

The rods that LMI and Allied sell used to be pretty much exactly the same .. no more though.

The LMI double action rod has left and right hand threads, one at each end, so that when you turn the rod one way, it is getting longer (or shorter) at both ends at the same time, thus producing either upward (or downward) thrust in the middle of the rod. These rods work twice as fast as normal rods, but need more force to turn them I found.

The new Allied rod has right hand threads at both ends, but not the same TPI ... so, when you turn the rod in one (or the other) direction the threads are moving the same direction into the nuts, but at different rates - this is where the 6:1 ratio comes in as far as how the rod moves, this makes it very smooth, and this is how the rod shortens or lengthens depending on direction of rotation.

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

I use one now!
So does Martin Guitars!
Just because you can get a sympathtic (sp) vibration from the rod to f.b. contact!
i had this happen 5 years ago -all I had to do was turn the nut a small amount but it really scares ya when you first hear it!
it's not something you want to hear !

I fit my rods tight-with .020 clearance between the f.b. and rod!
I glue my board on after fitting this piece(which is .020) and making sure there is a good glue joint!
I find a wooden (veener) cover stops the metal to hardwood rattle!!!!
I heard Martin uses a gasket type !


Mike

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Mike Collins

Thanks guys for the input. The gasket idea makes sense if the rattle is what you want to avoid. I just couldn't see that there is any real dispersal of force to the FB by using the spline, the the insulation of rattle makes sense. Thanks.
Donovan

I liked the action on the Allied rod but it seemed to me to be a tad more prone to the rattle/buzz/vibration than others I've used....without a spline that is!

GG

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Gwaltney Guitars

i ahve ben using LMI or Allied's double action for several years now. MY slots are perfect depth or with in .003-.005 anyway and will use a spline if the slot is deep end of this toerance but if flush I leave alone. I have had to file a tad of the nut ends now and then because the wel mad them a tad proud but that is really prety rare. I have no rattel issue once some tension was applied

I still use the LMI two way rod and just started using a spline. Mainly as another guard against rattle. I still fill the channel with caulk too. I had an early one (no caulk) that had a rattle that persisted at times even when the rod was snugged up. I had to drill a couple of small holes in the fretboard and inject rubber cement. Fortunately that worked.
Terry

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

Chucky my freind yep they look identical from a distance but what coach Tony says about the differences and details is spot on.

In addition the new Allied rod is stainless, has more precise welds that do not required filing or sanding down, and is MUCH smoother. I don't know that I would agree that it is more prone to rattling since I have not experienced that having used it twice now and the LMI rod many times.

The new Allied rod can be turned by hand with no wrench....... And you can adjust it as little or as much as you want. The LMI rod requires a wrench and seems to take a good deal of pressure to get it to move and when it does move IMHO it can move beyond where you want it to be.

Here are some pics from a previous comparison that I posted here on the OLF. They both weigh 119 grams.

Bet you can't tell them apart from this pic beyond the LMI tag on the lower one.



Notice the weld glob on the LMI rod?



Here is one of the differences, the lower (Allied) one has the weld recessed so no attention is required to remove the weld glob to get it to fit in a 1/4" channel.



The real difference is in how they work, again the Allied one is MUCH smoother and that makes it more precise too.

"DSC00610"

...Finally someone started building left handed ones!

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David White, Toronto

"All my favourite singers can't sing."

I started using the new Allied rods after reading about them here. Also started using
a spline after reading the thread Hesh mentioned by Mark Blanchard. It is the best
rod out there IMO. I also use some caulking under the rod.

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Anderson Guitars
Clearwater,Fl. 33755

You guys that are using caulk in the channel, what type of caulk are you using, and how much do you use?

GG

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Gwaltney Guitars

I'm interested in caulk type as well. I've heard horror stories about silicone contamination....
-j.

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“If God dwells inside us like some people say, I sure hope He likes enchiladas, because that's what He's getting”
-jack handy

David

As for caulk I can tell you that it is NOT GE silicon caulk...... I have not used caulk yet but I am interested in what people are having success with too.

latex is the cauk to use. not silicon

Go to the Allied Lutherie web site (link from here), click on truss rods, and read Mark Blanchard's installation instructions. This explains how his method of filler strip installation stops potential rattles and reduces backlash. It's not so much about having something between the rod and the bottom of the FB; it's about gently squeezing the two parts of the rod together.

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Todd Rose
Ithaca, NY

https://www.dreamingrosesecobnb.com/todds-art-music

https://www.facebook.com/ToddRoseGuitars/