What Size Carbon Fiber Rod For Neck Reinforcement?

[Mind Riot]

LMI had a clearance on some carbon fiber when I was ordering some parts, so I snagged two rods with my order. The site listed them as 5/8" x 3/8" x 17 5/8", and so did the confirmation e-mail.

When I got them, they were 5/32" instead of 5/8", the other dimensions matched. So I got these skinny little carbon fiber rods I'm not sure what to do with.

I'm new to the whole neck reinforcement thing, I get the idea and the principles but I have yet to do it myself. I see a lot of discussion about whether or not to use it, but not much about dimensions (or at least I haven't found it yet).

These things are much smaller than the stuff I see listed on LMI and Stewmac and whatnot, heck they're barely over a sixteenth thick.

They are stiff as heck, as can be expected, but I was still surprised. Bending them with the thin side up is virtually impossible for me, and bending them with the thin side facing sideways is still pretty stiff.

I'm in touch with LMI, but since it was a clearance item I don't think I'll be getting what I ordered in any case.

So what size of carbon fiber reinforcement do you guys put in your necks? Does anybody use thinner stuff like this, or is it pretty much standard to use something at least 3/16" wide or something?

The neck itself is cherry, with a jatoba scarf jointed headstock and it'll be getting a dual action truss rod from LMI, so I know the argument could be made that this neck doesn't need any more help to be stiff, but I'm curious about the tonal properties and such.

All thoughts appreciated!

[westhemann]

I am sure they will be fine...5/8" may have been a misprint....that is too,too wide for reinforcement.sounds more like a truss rod replacement than support rods.

Mine are 1/8" thick,and they work great(from stewmac)...I have used them a few times.Seems to create a "snappier" feel to the neck.

I have not found the to be needed in multi-lam necks,so I have not used them in a while,but I will be doing two one piece necks shortly and I will be using them in the 6 stringer...though in the 8 stringer I am planning on using two of the two way truss rods...just for kicks and because I think with a neck that wide with strings that thick on a neck as thin as I wish it to be that it would be a good idea to be able to control the twist...

[jmrentis]

Agreed. I think you are perfectly fine with those. The rods I had used were 1/8" X 3/8" X 18" from Los Alamos Composites. 1/8= .125 and 5/32= .15625, so yours are even thicker than mine or Wes' I believe. Just install them on the tall side, meaning route a 5/32" wide channel that is 3/8" deep, that will give you the most strength from that style rod. I actually prefer this size of rod because you keep the channel nice and thin and don't have to worry so much about carving into the CF channel when carving the neck, though make sure you measure everything out and keep an eye out anyway. FWIW I installed them so they followed the taper of the neck. I've seen it done both ways, where they are parallel to center line and where they follow the taper. When they follow the taper you are safer at the nut from carving into the channel because you can keep them closer to the center, whereas with the centerline style you're more likely to position them closer to the edge. Anyhow, best of luck, they should work out great for you. J

[Mind Riot]

Thanks fellas. It turns out I won't be needing these for this neck.

I thought I was using cherry for the neck laminates because the owner of the shop who gave me the wood said this whole pile was cherry. Turns out the whole pile was jatoba (Brazilian cherry). I wasn't familiar with either regular cherry or jatoba before this project so I didn't know the difference though I did notice the "cherry" I was working with was much harder than I thought it would be.

Now I get to look forward to carving this neck out of one of the hardest woods in the world. It's a four piece laminate of jatoba with a scarf jointed jatoba headstock and a double action truss rod.

I kind of think carbon fiber reinforcement would be overkill.

Should be interesting anyway.