Neck relief problem in newly built bass

fivestringcult · #1 01-16-2009, 09:26 AM

I finally received the bass featured in this thread: Korina/Maple 5 String for Dan over Christmas, and whilst I'm extremely happy with it on the whole, I've been having some trouble getting any relief into the neck.

For those who don't wish to read through the entire thread, the neck is maple with two carbon rods and the truss rod inside, an ebony fretboard, 35" scale length. It's been perfectly straight since day one with the truss rod just barely tightened to "biting point", and at standard tuning with string gauges 130 - 40 it just doesn't want to bend at all. Good sign for future stability perhaps, but an absolute pain for setting up!

So far, Simo (who has done an outstanding job of building this thing) and myself have tried gradually tuning it higher - half a step up at a time, then another half a step higher after a day or two - to add in some extra tension. Whilst the neck has moved temporarily when left this way, it straightens up again right back to where it was as soon as I try returning it to standard tuning, even after a week or more of the additional tension to try and help it along. I'm planning to change the strings for a set of 135 - 45 gauge, but I'm still not convinced they'll give enough tension for me to leave it in standard tuning yet.

I've had the bass for almost a month now, and it still doesn't seem to have realised it's not a tree any more. I know I'm prone to being impatient, but should it really be taking this long to settle in? Just wondered if anyone else here has had a similar experience really, to put my mind at rest.

JustDavid · #2 01-17-2009, 06:49 AM

Maybe it has settled in.

For how I visualize it, the truss rod at minimum tension is your 'minimum string tension' setting.

More relief with uptuning then restoration to status quo after a week seems to me like how necks work.

It's not a tree anymore. It's a tree with 2 carbon rods in it.

XylemBassGuitar · #3 01-17-2009, 09:07 AM

The heavier gauge set of strings is probably your best bet...

dmusic148 · #4 01-17-2009, 09:14 AM

Yep, heavier strings and/or different type, for example DR Low Riders string up with a bit more tension.
Aside from that I'm afraid you'd need to re-profile the fingerboard. I fell into this trap once, that's what I had to do. Looks possible on your bass-the board looks quite thick.

etoncrow · #5 01-17-2009, 12:55 PM

I have two rods and ten screws in my spine and a plate with four screws in my left wrist; maybe that's why i don't get much relief either...

fivestringcult · #6 01-20-2009, 06:58 PM

Well I've got the 135's on it now, and it's improved things a bit. It's still not perfect but it's a lot closer. Not really sure what else I can do really except wait until the weather gets a bit warmer. I don't think shaving a couple of mm off the fingerboard would make a great deal of difference in all honesty - I think it probably has more to do with the fat wedge of quarter-sawn maple that makes up the rest of the neck. As for the carbon rods - although as I understand it they do help with stability and can reduce any possible dead spots, they're not so stiff as to work against the wood to a great extent are they?

Pilgrim · #7 01-20-2009, 08:06 PM

135's????

Are you sure there isn't a tugboat around that could lend you a spare hawser or two?

Howzabout putting the set of strings you plan to use on it, tuning the way you're going to tune it, and playing it? I'm a big believer in treating them the way you're going to treat them from the start. I darn sure wouldn't modify a new bass like yours until I had a good chance to let everything settle in.

fivestringcult · #8 01-21-2009, 05:01 AM

Haha, yeah that's what I'm going to do now. I'm quite used to the feel of 135's now anyway to be honest, I switched to them a while back on my 34" scale 5-stringer for some extra tight low B goodness.

At least this bass is playable without buzzing too much everywhere now, even if the setup isn't perfect. So I can still make use of it whilst I'm waiting for things to settle.

ga_edwards · #9 01-21-2009, 05:48 AM

I remebered reading this article ages ago about 'helping the trussrod' when there's too much forward bow by using a length of wood and some clamps to force some back bow into it.
http://www.bassplayer.com/article/tr...b/dec-06/24300

I wonder if you could take reverse this and force some bow into it?

But +1 to giving it plenty of time to settle before doing anything drastic like this. Could take a few months till the wood is finally where it wants to be.

dmusic148 · #10 01-21-2009, 06:08 AM

Quote:

Originally Posted by fivestringcult

Well I've got the 135's on it now, and it's improved things a bit. It's still not perfect but it's a lot closer. Not really sure what else I can do really except wait until the weather gets a bit warmer. I don't think shaving a couple of mm off the fingerboard would make a great deal of difference in all honesty - I think it probably has more to do with the fat wedge of quarter-sawn maple that makes up the rest of the neck. As for the carbon rods - although as I understand it they do help with stability and can reduce any possible dead spots, they're not so stiff as to work against the wood to a great extent are they?

Just to clarify my earlier post:
Here's what my luthier and I did, when I had this problem on a fretless.
1) remove strings and nut.
2) adjust neck to create a little back-bow, which it wants to do anyway once the strings are removed. He knew the correct amount, I don't remember.
3) With the neck back-bowed, plane the fingerboard flat. That's the key. Then re-radius and polish.

Now, when string tension is applied the fingerboard will take on a forward bow, providing relief. Adjust truss rod to taste. In your case you might be able to get a decent amount of relief by simply re-leveling the frets in a similar manner. Worst case it would require a re-fret. Totally doable.

The carbon rods are a LOT stiffer than the surrounding wood. Depending on their size, they may even be stiffer than all the wood in the neck, all by themselves. Carbon fiber is incredibly strong stuff.

fivestringcult · #11 01-21-2009, 08:22 AM

Ah, that makes a lot more sense now. Thanks for clarifying.

Still, hopefully it won't come to that. If I'm still in the same situation in 6 months time then maybe I'll give it some more thought.

Pilgrim · #12 01-21-2009, 12:39 PM

Quote:

Originally Posted by fivestringcult

Still, hopefully it won't come to that. If I'm still in the same situation in 6 months time then maybe I'll give it some more thought.

That sounds like a wise statement!