Truss rod refinements, rattle, what is acceptable?

[Ash Nightingale]

Hi Folks

So the truss rod and its installation is something I have been pondering recently so i wanted to get peoples opinions.

On one of my recent necks i did a test, if the neck was held with the truss rod in neutral position, and you give a hard slap to the back of the neck with your hand, you can hear the two way truss rods rattling together. However a 1/4 turn of the allen key and the rattle goes away. This amount of adjustment is not enough to even move the neck it just takes the rods from "neutral" to "engaged".

So my question is, is this normal and acceptable? Do the truss rods by definition rattle in the neutral position (im talking about the type where the round rod at the back with opposing threads has heat shrink and there is a flat bar in front of that)?

I have read threads about using silicone or caulk in the groove which feels totally wrong to me on several levels. I tried wrapping the truss rod in PTFE tape once and it affected the curve of the rods, it was no longer an even curve, so i removed the tape before gluing the fret board on. So I always revert to my standard way which is to simply install the truss rod into a reasonably tight fitting slot, not an interference fit, but snug, no glue, no tapes.

Does anyone know a method or maybe or a type of truss rod to give 100% rattle free results?

All the best
Ash Nightingale

PS ive never had problems or comments back about any of my guitars regarding rattling truss rods however my concern is if a fingerstyle player decides to set up the guitar in 100% neutral truss rod position and proceeds to tap the fretboard its possible it could rattle if they hit it hard enough. So im pondering a way to eliminate this concern in the interest of refinement of future guitars.

[Coop47]

Hi - I just went through this with a new guitar and eventually decided to return it because in addition to rattling, the truss rod was pretty much stuck and I didn't want to force it. However, in the course of talking to a few people and reading articles and forums, most seemed to think that it was acceptable so long as the rod could be "engaged" with a small turn. Put another way, if my guitar was acting the same as yours, I probably would have kept it and not worried about it.

Hope that helps.

(Edit - I just read your PS and see that my answer my not help you at all. Sorry. I was trying to answer your first question about what's normal and acceptable.)

[Bruce Sexauer]

I tightly wrap my double rod in electrical tape so it won’t rattle when loose, and it works well enough. Another common fix is to put a dab of silicone caulk between the rods before installation. No amount of rattle is acceptable.

[mirwa]

If you are using a conventional style two way truss rod where the bottom rod is wrapped in a heat shrink plastic or teflon then the only way it will rattle even in the neutral position is by not putting something between the flat bar and your fret board, unless of course the truss rod slot cut into the neck is oversize

Steve

[Rudy4]

Originally Posted by Ash Nightingale

Hi Folks

So the truss rod and its installation is something I have been pondering recently so i wanted to get peoples opinions.

On one of my recent necks i did a test, if the neck was held with the truss rod in neutral position, and you give a hard slap to the back of the neck with your hand, you can hear the two way truss rods rattling together. However a 1/4 turn of the allen key and the rattle goes away. This amount of adjustment is not enough to even move the neck it just takes the rods from "neutral" to "engaged".

So my question is, is this normal and acceptable? Do the truss rods by definition rattle in the neutral position (im talking about the type where the round rod at the back with opposing threads has heat shrink and there is a flat bar in front of that)?

I have read threads about using silicone or caulk in the groove which feels totally wrong to me on several levels. I tried wrapping the truss rod in PTFE tape once and it affected the curve of the rods, it was no longer an even curve, so i removed the tape before gluing the fret board on. So I always revert to my standard way which is to simply install the truss rod into a reasonably tight fitting slot, not an interference fit, but snug, no glue, no tapes.

Does anyone know a method or maybe or a type of truss rod to give 100% rattle free results?

All the best
Ash Nightingale

PS ive never had problems or comments back about any of my guitars regarding rattling truss rods however my concern is if a fingerstyle player decides to set up the guitar in 100% neutral truss rod position and proceeds to tap the fretboard its possible it could rattle if they hit it hard enough. So im pondering a way to eliminate this concern in the interest of refinement of future guitars.

It's a good question.

Your thoughts on giving the rod just a bit of tension would be the best idea to me. Since you're not actually adding back bow or moving the neck then IMHO what you're doing is adding support to the neck to prevent bowing in the future as time and string pull eventually work their magic. If the rod just at the point where it will resist future movement then that should be a good dose of preventative medicine.

I switched to the LMI double-acting rod a while back because I'm making necks with an initial through channel route which permits me to choose either headstock or heel adjustment point based on instrument type and desired access point, plus it makes the rod removable / replaceable in the future should it become necessary. To do that requires a clean channel and sized so the rod can be slipped in or out. That would normally be a recipe for truss rod buzz, but I add that small bit of "pre-tension" as you mention and that prevents the rod from moving in the channel.

All that said, I don't see anything wrong with what you're doing.

[Simon Fay]

I would never want any rattle at any position or tension. I would also never use silicone or caulk. I use a t-rod made by Mark Blanchard that is similar to the LMI double-action trod. I install a mahogany filler strip above the truss rod that basically removes all the slack in the rod. You don't want to clamp this filler strip to tightly or it can make the trod hard to turn -- some spring clamps will provide more than enough clamping power. After you install the filler strip, tru the neck once again and then glue on the fretboard.

This makes trod removal a nightmare - so make sure the trod is well made - hence, the reason I buy mine from Mark Blanchard. I can rap the back of my neck blanks and I get a nice ring just the same as the neck without the truss-rod. Anything less and I wouldn't be happy. Even the small details can make a difference and that's how I try to approach my builds.

[Ash Nightingale]

Originally Posted by Coop47

Hi - I just went through this with a new guitar and eventually decided to return it because in addition to rattling, the truss rod was pretty much stuck and I didn't want to force it. However, in the course of talking to a few people and reading articles and forums, most seemed to think that it was acceptable so long as the rod could be "engaged" with a small turn. Put another way, if my guitar was acting the same as yours, I probably would have kept it and not worried about it.

Hope that helps.

(Edit - I just read your PS and see that my answer my not help you at all. Sorry. I was trying to answer your first question about what's normal and acceptable.)

Thanks, Good to hear from the point of view of a guitar owner. The idea of having a client be not happy with one of my guitars is the kind of thing that keeps me up at night. That sounds like the last thing you wanted with a new guitar.

[Ash Nightingale]

Originally Posted by Bruce Sexauer

I tightly wrap my double rod in electrical tape so it won’t rattle when loose, and it works well enough. Another common fix is to put a dab of silicone caulk between the rods before installation. No amount of rattle is acceptable.

Thanks that's good advice. I am planning to make a few sample necks to play around with different truss rod installations. The idea of some kind of tape or, i was thinking, heat shrink around the middle to hold the two rods together, could be the way forward.

And agreed no amount of rattle is acceptible, i think that was my gut feeling hence starting this thread

[Ash Nightingale]

Originally Posted by mirwa

If you are using a conventional style two way truss rod where the bottom rod is wrapped in a heat shrink plastic or teflon then the only way it will rattle even in the neutral position is by not putting something between the flat bar and your fret board, unless of course the truss rod slot cut into the neck is oversize

Steve

I generally put a filler strip over the truss rod. I think this would only prevent buzz in and of itself if it was clamped in the middle to press the two rods together which i have always avoided due to concerns about reducing the effectiveness of the rods through changing their shape or applying too much friction to the back rod which has to turn.

This could be a solution though to apply gentle clamping force to the filler strip in the middle of the rods where they are likely to rattle. I think this is what Simon Fay suggests in his comment.

thanks for chippin in
Ash

[Ash Nightingale]

Originally Posted by Rudy4

It's a good question.

Your thoughts on giving the rod just a bit of tension would be the best idea to me. Since you're not actually adding back bow or moving the neck then IMHO what you're doing is adding support to the neck to prevent bowing in the future as time and string pull eventually work their magic. If the rod just at the point where it will resist future movement then that should be a good dose of preventative medicine.

I switched to the LMI double-acting rod a while back because I'm making necks with an initial through channel route which permits me to choose either headstock or heel adjustment point based on instrument type and desired access point, plus it makes the rod removable / replaceable in the future should it become necessary. To do that requires a clean channel and sized so the rod can be slipped in or out. That would normally be a recipe for truss rod buzz, but I add that small bit of "pre-tension" as you mention and that prevents the rod from moving in the channel.

All that said, I don't see anything wrong with what you're doing.

I have toyed with the idea of a truss rod that could be removed through the headstock. I think this is a good idea as if part of the truss rod gets glued in place this can change its effect on the neck, it creates more of an s shape rather than a smooth curve, i have seen this happen. So being able to slide the truss rod in after all glue ups have cured is quite a reassuring and attractive idea to me. As i previously mentioned something like heat shrink could help avoid rattle in this scenario. I am going to make some sample necks and come up with a method I am 100% happy with. One of these samples will include adding the truss rod later and see how this works out.

Thanks for your comments
Ash Nightingale

[Ash Nightingale]

Originally Posted by Simon Fay

I would never want any rattle at any position or tension. I would also never use silicone or caulk. I use a t-rod made by Mark Blanchard that is similar to the LMI double-action trod. I install a mahogany filler strip above the truss rod that basically removes all the slack in the rod. You don't want to clamp this filler strip to tightly or it can make the trod hard to turn -- some spring clamps will provide more than enough clamping power. After you install the filler strip, tru the neck once again and then glue on the fretboard.

This makes trod removal a nightmare - so make sure the trod is well made - hence, the reason I buy mine from Mark Blanchard. I can rap the back of my neck blanks and I get a nice ring just the same as the neck without the truss-rod. Anything less and I wouldn't be happy. Even the small details can make a difference and that's how I try to approach my builds.

I agree totally with your viewpoint on this. I am striving to build high end guitars and its the small details that make the difference.

I have always avoided clamping the middle of the filler strip as i was worried that would change the shape of the rod or grip the back rod too much and stop it from turning as you mention. but if you say you apply light clamping pressure to the middle of the filler strip and this works fine for you then I will definitely have to give that a try.

Thanks
Ash

[Robin, Wales]

You are going to love this!



This is the truss rod I took out of a brand new neck made by one of the OEM guitar workshops in China. And, yes, that nut has been welded on so it won't move!!! Obviously, I couldn't get the nut to turn (despite eventually resorting to lube and heat) and so I ripped the neck apart to see what was going on. The relief was actually OK on the instrument but truss rod function was one of the list of checks I did on every instrument and so caught this guitar before it went for sale. I've never had another like it. But why would someone drop this total piece of junk into an otherwise nicely made neck? I did sent some very colourful feedback to the factory who apologetically sent a new guitar. I kept the rod as a memento!

[tadol]

Originally Posted by Ash Nightingale

I have toyed with the idea of a truss rod that could be removed through the headstock. I think this is a good idea as if part of the truss rod gets glued in place this can change its effect on the neck, it creates more of an s shape rather than a smooth curve, i have seen this happen. So being able to slide the truss rod in after all glue ups have cured is quite a reassuring and attractive idea to me. As i previously mentioned something like heat shrink could help avoid rattle in this scenario. I am going to make some sample necks and come up with a method I am 100% happy with. One of these samples will include adding the truss rod later and see how this works out.

Thanks for your comments
Ash Nightingale

Hi Ash - Roger Siminoff did a presentation to the NCAL group via Zoom in September, specifically on truss rods. He made the truss rod you are considering - you may want to watch this (sorry the record button didn’t get hit earler).

https://vimeo.com/455334910

[mirwa]

Originally Posted by Robin, Wales

yes, that nut has been welded on so it won't move!!! Obviously, I couldn't get the nut to turn (despite eventually resorting to lube and heat) and so I ripped the neck apart to see what was going on.

That is a very common design, the head is actually a three piece design, I know this as I make them.

You have a spacer, truss rod nut and an outer collar, the outer collar and spacer are welded together, the truss rod nut is captured in the outer collar, you then weld the assembly to a flat bar.

Yours was likely rusted up

Steve

[Robin, Wales]

Originally Posted by mirwa

That is a very common design, the head is actually a three piece design, I know this as I make them.

You have a spacer, truss rod nut and an outer collar, the outer collar and spacer are welded together, the truss rod nut is captured in the outer collar, you then weld the assembly to a flat bar.

Yours was likely rusted up

Steve

Thanks for this. That's really useful info. There's no sign of any potential movement on the nut in the truss rod I have. I have bent hex keys trying to turn it despite soaking the bar in oil. So I don't know why it will not operate. A simple test before installation was all that was needed!!!!!!!