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Need to straighten a bent neck


Batfastard
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What the best way to straighten this out?
[IMG]http://i912.photobucket.com/albums/ac323/Bat_fastard/2011-10-31110133.jpg[/IMG]

I loosed off the truss rod before embarking on the modifications (see link in my sig) and the strings on it now are a lower tension than the roundwounds I had on it before the mods.
I have no work space to speak of and Idonot have any access to clamps at the mo.
Cheers for any advice.

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No idea as I gave the old stings to my brother for his bass. The neck wasn't straight when I bought the bass but it was never this bad. The reason i modded it in the first place was that it didn't matter whether it went on a fire or got chopped about. The only thing is that when i first reassembled it as a fretless it felt good to play, the neck was still a bit fat for my liking but it was playable, now I'd like to keep it.

Bits of plastic egdeing from and old computer desk as they were easy to trim to shape.

Edited by Batfastard
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[quote name='Batfastard' timestamp='1320062211' post='1421669']...Bits of plastic egdeing from and old computer desk as they were easy to trim to shape.
[/quote]
The neck straightens out when not under tension though yes? I suspect your bits of plastic (and probably air pockets and gaps) compress under tension thus leading your bow.
I'm still lost as to how tighten up the tr makes it worse though... unless it introduces a squiggle instead of countering the bow.

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[quote name='Batfastard' timestamp='1320063290' post='1421686'].... My guess it that it was bowed for so long the rod took that shape.
[/quote]
It's very doubtful. A tr is a dynamic device with a threaded section which in the case of a dual action tr, physically alters it's shape by shortening and lengthening in conjunction with a fixed bar. A single action tr will straighten out the tighter it gets - shortest distance between two points and all that.

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[quote]Have you tightened the truss rod with no string pull on the neck & applying hand pressure to relieve the neck before tightening?
What happens> Can you feel the truss rod nut 'working' on the thread or not?[/quote]

Yeah, and I can feel the thread biting.


[quote]It's very doubtful. A tr is a dynamic device with a threaded section which in the case of a dual action tr, physically alters it's shape by shortening and lengthening in conjunction with a fixed bar. A single action tr will straighten out the tighter it gets - shortest distance between two points and all that.[/quote]

Thats true, but there is the fact that the rod is a long thin piece of metal and it can be depresssingly easy to deform something like that.

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[quote name='Batfastard' timestamp='1320068403' post='1421804']
Thats true, but there is the fact that the rod is a long thin piece of metal and it can be depresssingly easy to deform something like that.
[/quote]

Surely that'd only be if it was forced beyond its elastic limit? Given that it's safely encased in wood and a truss rod curve is pretty gentle, I'd be surprised if you could do it. Besides, for a single action rod it wouldn't matter anyway - the leverage against the neck channel with the anchor points at either end would still force it towards straightening. Dual action...they often tighten the other way to normal right? You might have to go through a bit of slack where not much appears to happen before it starts to push the other way.

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If you can't sort it out with the truss rod, take out the plastic fret fillers and put maple/ash veneer in.

If that doesn't sort it then other options are:

A new and very thick fingerboard from ebony, pau ferro, gonzales or similar dense hardwood

A stainless steel fingerboard on top of the old one.

and/or reinforcement using stainless steel or graphite composite rods in the neck.

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[quote name='Kiwi' timestamp='1320110528' post='1422546']
If you can't sort it out with the truss rod, take out the plastic fret fillers and put maple/ash veneer in.

If that doesn't sort it then other options are:

A new and very thick fingerboard from ebony, pau ferro, gonzales or similar dense hardwood

A stainless steel fingerboard on top of the old one.

and/or reinforcement using stainless steel or graphite composite rods in the neck.
[/quote]
:) :)

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[quote name='LawrenceH' timestamp='1320107184' post='1422525']

Surely that'd only be if it was forced beyond its elastic limit? Given that it's safely encased in wood and a truss rod curve is pretty gentle, I'd be surprised if you could do it. Besides, for a single action rod it wouldn't matter anyway - the leverage against the neck channel with the anchor points at either end would still force it towards straightening. Dual action...they often tighten the other way to normal right? You might have to go through a bit of slack where not much appears to happen before it starts to push the other way.
[/quote]

I have to say I think Lawrence is right here. The truss rod is tensioned to straighten the curve in the wood. Even if the rod did get bent (extremely unlikely) putting it under tension would still have the desired effect of reducing the curve as the tension would cause it to straighten. I think it may be that its just not under enough tension to counteract the pull from the strings...

And joking aside (Thanks Charic btw :) ), if tightening the truss rod makes it worse are you sure you're tightening it (they don't all turn the same way)? ALso, once you have adjusted, its sometimes a good idea to let the thing settle for a while before adjusting again - especially if you have had it completely off for a bit.

I don't think the filling in the fingerboard will make that much difference IMHO.

The only other suggestion would be to go to a reputable repair guy/luthier - theres a list of recommended people here, it might at least be worth showing someone and having a chat about whether its worth doing any more work to fix it.

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I don't think the fret filler is the problem, I've played on a bass that was de-fretted and the had the slots left open, it worked fine.
You have nothing to lose, go nuts with the allen key see what happens,. I can't imagine how the truss rod would get bent, it's more likely to be a problem with the threaded portion. There's only a short thread (just beyond the silver bit) it sound to me that it's stripped or damaged in some way. It is possible to replace a truss rod

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Sorry if I came across as ignoring you mate. Have tried your advice of tightening the truss rod. I've read all the advice in this thread and appreciate it. At the moment the neck is strappedd to my bedframe and squashed against a wall with some packing to make the nut clear the wall in the hope that my improvised clamp will work otherwise it'll be a new truss rod or neck which i cannot afford.

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