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I have two necks I'm building with LMII double action rods. I keep reading about how people just install these things with no filler strips, no caulk and no problems, so I decided to try it. Grrrr....one of these days I will learn to just go with what I know and stop experimenting....lol.

Both of them rattle...not a HUGE big deal as it's minor when it's snugged up, but definitely annoying to me. On one of them, though, the rod is actually ringing like a tuning fork. It's incredibly loud. I've never had that happen on any rod before.

What I don't understand is how can this thing be ringing when it's tight against the finger board AND snugged down. Doesn't matter how tight I make it...the ring just gets higher in pitch. What the heck is ringing?

Anyhow, short of removing these fingerboards, ripping everything apart and reinstalling them, anyone have any ideas on how to fix this? The boards were just glued on yesterday do they'll probably come off with just a heat gun and some gentle prying and probably even be reusable.

Thanks for any advice.

Some critical info I left out. I hadn't planned on installing fret markers on the front of the fingerboard, but I wouldn't mind. I was thinking along the lines of turning the rod to counterclockwise to bring the bar away from the fingerboard, drilling for round fret board markers, and injecting some sort of goop of some kind to kill the ringing and rattle. I wouldn't know what to use for the goop, but I think this may work OK....what do ya'll think?

It's just a couple of prototypes, by the way...I'm not butchering someone else's guitar!

The bottom rod is round, and raised off the floor of the slot slightly. That's what's ringing like a tuning fork.

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Old growth, shmold growth!

Drilling holes in the fretboard, fret slots, or marker locations and injecting rubber cement works well. I've done it twice. I have drilled around the 2nd or 3rd fret and the 10th or 11th and injected into the upper end until I could see stuff coming out the lower. Practice on scrap and find a hole diameter that gives a snug fit with your needle.
Mine were like yours. LMI rod with no shim or caulk on a couple of my early ones. Frank Ford recommended thinning the cement with Naptha but full strength worked best for me. I just drilled through the ebony fretboard and plugged with a sliver of Ebony, CA, and dust and it was invisible.

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

Thank you! What type of cement did you use?

Any suggestions for the ringing? Is it really that bottom rod? If so, maybe a similar solution would work from the back side of the neck?

Anyway, thank you so much. I don't know what possessed me to try the LMI rod bare, but I figured "It's just a couple of prototypes...what's the worst that can happen?". LOL...holy cow is it ever irritating!

edit: I see you said "rubber" cement. Got it! Thanks again.

Duh Padma says to inject honey into the cavity.
He says it makes it sound sweet.

It's obvious he's from overseas. Here in the US we inject high fructose corn syrup.

I've had this happen to me once on a guitar and started using silicone caulk. Never happened again. It IS very annoying. I gave the guitar to my dad and it looks pretty sitting in the corner though And with mine if it starts to rattle all I have to do is tweak the rod and it goes away for a few more hours of playing. I never could figure that one out.

But that's a clever idea to drill holes and inject.

I've injected a lot of buzzing truss rods. Better than rubber cement is catalysed low viscosity silicone caulk. It doesn't shrink, and it doesn't stick to threads. I use GE RTV 11 (McMaster #74965A687) It will just barely flow through a 16 gauge needle. If you drill at the correct angle, you can go in from the bottom of a fret slot, and hit the space between the two rods of a double acting rod. Confirm that you've hit the space by blowing compressed air in the hole, and having it come out at the adjusting end of the truss rod. The air will lift a piece of paper towel placed over the sound hole. It usually takes nearly 10cc of silicone for a double acting rod. I inject at the second fret, and keep going until it flows out inside the guitar. Masking tape on surfaces at both ends will make clean up easier. This has worked great for me on a few dozen repairs. (When things go wrong at a factory...) The silicone completely cures the buzzing, and the truss rod still functions smoothly.

Would it be possible to "pour" thin silicone past the end of the rod with the adjusting nut removed?
The danger with with silicone, of course, is contaminating anything in the room that could come into contact with something that requires finishing. (Think fisheye)
Could about type of material that will set up and take up space be used? Thinned glue?
Nelson

I can't because it's the LMI double action rod. There's not a sliver of space to inject anything without drilling. I also suspect that you probably need a second hole somewhere as a vent, though if you have enough room it'll just vent out the original hole I suppose. The only reason I had this problem in the first place is I got cute and didn't take the extra 15 seconds to bed it in caulk as I normally do. I guess that'll teach me.

Try "setting" the rod.
Put the adjustment wrench on and give it a good tap with a small
hammer.
Mike

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Mike Collins

So here's the outcome:

On the first one I tried, I went through the fingerboard and found that I really couldn't inject much. That rod was solidly against the fingerboard. I was able to play with the rod back and forth and it did suck a little bit in...not enough to stop the rattle. Apparently, I play with something a little too much and the rod broke. I'd never had that happen before. It didn't even feel like it was breaking. It just kinda gave a little snap and that was it. I wasn't torquing very hard. I'm starting to think that I got a bum rod to begin with. I've used these rods before and I know I was no where near torquing it very hard at all. C'est la vie. I just built a new neck...er...almost anyhow. I still have to glue on the veneer and the fingerboard, but other than that it's no big loss other than the annoying loss of some really nice wood! I may attempt to take it apart and fix it someday, but before I apply heat I want to be really sure that rubber cement is fully cured.

On the other neck, I decided that I wasn't going to fool around at all. I drilled sideways through the side of the neck blank, just under the fingerboard. After I shape the neck, I'll fill whatever mess I made with dust and glue, and just continue on. The rubber cement completely eliminated the singing rod, by the way.

Thanks again for all the help.

John,
I don't use double action rods, and I'll be the first to admit that I've only built four instrument necks. Still, this trick might be useful to you. Don't worry about caulk, etc. on the next one. Instead, just wrap the rod with teflon plumber's tape until it's a snug, press fit into the cavity. I use single action rods (compression rods) installed this way, with a filler strip between the top of the rod and the fingerboard. Seems to me it ought to work with double rods, too. I didn't invent this technique. It's widely used. Try it on your next one. If it doesn't work for you, you can still inject rubber cement later. Another, not-quite-related tip: If you or any of your buddies also happen to play saxophone, nothing works better to refresh a compressed neck cork than a few wraps of teflon plumber's tape. You'll never need to use cork grease again!
Patrick