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Install 2 way truss rod upside down
http://luthiersforum.com/forum/viewtopic.php?f=10101&t=35486
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Author:  John Coloccia [ Wed Feb 22, 2012 10:44 am ]
Post subject:  Install 2 way truss rod upside down

Anyone see a problem doing this? It's a 2 way rod so I can't imagine it makes any difference which side is up. It's going into a Fender style neck, and after mulling over my options for truss rod access, I decided on a traditional heal access but was thinking I'd put the Allied Lutherie rod in upside down to allow access with the neck bolted on (it puts the nut at the top instead of the bottom.

Author:  DannyV [ Wed Feb 22, 2012 11:31 am ]
Post subject:  Re: Install 2 way truss rod upside down

I would be asking that question to Allied. He knows best.

Author:  John Coloccia [ Wed Feb 22, 2012 11:33 am ]
Post subject:  Re: Install 2 way truss rod upside down

I will as soon as they open, but they're in CA so I thought I'd try here first. I'm twiddling my thumbs waiting to make a batch of necks. :)

Author:  Corky Long [ Wed Feb 22, 2012 11:37 am ]
Post subject:  Re: Install 2 way truss rod upside down

Don't think it will work. Even though it's a two way truss rod, it's designed to apply most of the force in one direction (assuming the two way rod is what I'm accustomed to using, a round threaded adjusting rod, under a flat metal "spring" for want of a better term.) The rod turns and flexes the spring to provide the tension to counter tension of springs. Turn in the other way and the spring goes concave. I don't think it provides near the same tension in "concave mode". My two cents - YMMV.

Author:  Pat Hawley [ Wed Feb 22, 2012 1:10 pm ]
Post subject:  Re: Install 2 way truss rod upside down

I think the only "issue" might be in having a non-conventional direction for turning the nut when making adjustments. If whoever is doing the adjustment is not aware that the truss rod in this guitar works "backwards" they may do some damage before they figure out what's going on.

I don't agree with Corky's spring theory but perhaps I just don't understand what he is saying.

Pat

Author:  Daniel Minard [ Wed Feb 22, 2012 1:13 pm ]
Post subject:  Re: Install 2 way truss rod upside down

Personally. I think it's not a great idea for the reasons already mentioned. Also... The flat, top bar spreads the load under the fingerboard better than the rod will... Even if you glue a thin filler strip over the truss rod.
I have to ask... Why do you want to put the rod in upside down?

Author:  John Coloccia [ Wed Feb 22, 2012 1:21 pm ]
Post subject:  Re: Install 2 way truss rod upside down

I called Allied and we spoke about it a bit. After we scratched our heads for a couple of minutes, he made an excellent point that it puts less bearing surface against the FB, and could potentially split it. I would really have to bury it a bit deeper and use a thicker filler strip but that defeats the purpose. We both agreed that it should work just fine, though. Upon thinking about it some more I decided that the backwards turning rod coupled with dubious gains in nut position just makes the whole thing not worth it.

Author:  John Coloccia [ Wed Feb 22, 2012 1:23 pm ]
Post subject:  Re: Install 2 way truss rod upside down

Daniel Minard wrote:
Personally. I think it's not a great idea for the reasons already mentioned. Also... The flat, top bar spreads the load under the fingerboard better than the rod will... Even if you glue a thin filler strip over the truss rod.
I have to ask... Why do you want to put the rod in upside down?


Having the rod upside down moves the nut a bit closer to the FB, making it easier to adjust without removing the neck...also if I wanted to make this a set neck.

Instead, I will just cut a recess in the body at that point and supply a stubby wrench with the guitar. That should work fine.

Author:  Pat Hawley [ Wed Feb 22, 2012 2:58 pm ]
Post subject:  Re: Install 2 way truss rod upside down

John Coloccia wrote:
After we scratched our heads for a couple of minutes, he made an excellent point that it puts less bearing surface against the FB, and could potentially split it.


If this is true somebody better tell Stew-Mac to re-design their "Hot Rod" truss rod.

Pat

Author:  Mike Dotson [ Wed Feb 22, 2012 3:04 pm ]
Post subject:  Re: Install 2 way truss rod upside down

Exactly what I was thinking. :mrgreen:

Author:  Mark Groza [ Wed Feb 22, 2012 3:34 pm ]
Post subject:  Re: Install 2 way truss rod upside down

A two way rod works both ways and if the round rod will split a fretboard, it could also split the back of the neck right? So there would not be a difference. ;)

Author:  Freeman [ Wed Feb 22, 2012 4:26 pm ]
Post subject:  Re: Install 2 way truss rod upside down

Here is a SM hot rod style t/r adjusted perfectly flat

Image

and with one turn on the adjuster

Image

(I like to show those to people who say "just give the truss rod a turn or two")

In their instructions, StewMac says " The Hot Rod® fits in a straight channel. For proper operation, this truss rod must be installed so that the active rod (the rod with the adjustment nut) is below the passive rod. A wooden filler stick is not required"

Author:  Daniel Minard [ Wed Feb 22, 2012 7:47 pm ]
Post subject:  Re: Install 2 way truss rod upside down

Mark makes an excellent point... Which I thought out AFTER I posted my last note.
Duh.....

Author:  John Coloccia [ Wed Feb 22, 2012 8:29 pm ]
Post subject:  Re: Install 2 way truss rod upside down

Well to be fair, once it dawned on me that the rod would work "backwards", I decided to kill the idea so I didn't really put much thought into the rod pushing against the fingerboard and whether or not that would be OK. The fact is that the nut position moved so little that it's just not worth the trouble to have a backwards rod.

Author:  kfish [ Thu Feb 23, 2012 6:58 am ]
Post subject:  Re: Install 2 way truss rod upside down

John Coloccia wrote:
Well to be fair, once it dawned on me that the rod would work "backwards", I decided to kill the idea so I didn't really put much thought into the rod pushing against the fingerboard and whether or not that would be OK. The fact is that the nut position moved so little that it's just not worth the trouble to have a backwards rod.


I've owned several National guitars. Not sure if they are all this way but the truss rod in the "tricone" and the "N" that I had worked backwards. Very confusing the first time I had to work on the action.

Kent

Author:  murrmac [ Thu Feb 23, 2012 9:59 am ]
Post subject:  Re: Install 2 way truss rod upside down

EDIT :post now redundant ...

Author:  Tai Fu [ Thu Feb 23, 2012 11:55 am ]
Post subject:  Re: Install 2 way truss rod upside down

I hate truss rods that adjusts in 2 directions... if the neck wood is properly dried and selected such a rod isn't needed anyways.

I had adjusted a Takamini G series guitar that has such a truss rod, but I wasn't aware of it so I just turned it and it felt it was tightening but it wasn't until the customer noticed that the neck was becoming more concave that I stopped and turned the other way. I was lucky that I didn't end up damaging the neck.

Author:  Freeman [ Thu Feb 23, 2012 12:22 pm ]
Post subject:  Re: Install 2 way truss rod upside down

murrmac wrote:
Just to show the second pic (wrong IMG bracket, "{" instead of "[" ) ...


Fixed

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