SDCurlee truss rod saga - advice and comments welcomed

[yodedude2]

hi y'all, i wish to document my repair efforts on my S. D. Curlee bass. it is a Yankee II model. the issue with this bass is that, as the truss rod is tightened, the neck kinks upward in the 5th fret area. the neck will not support a proper or playable relief; as the neck kinks, the strings fret out. without any tension on it, the neck appears quite straight. i suspect it has a bent truss rod. i recently removed the bolt-in neck, removed the truss rod nut and four bent washers from the butt end of the neck, and took this picture:



one can see this is a five piece neck with an integrated fretboard. the truss rod sits in the bottom of its channel. it does not rest there--it has tension on it. one must use light force to lift it from the bottom of the channel; when released, it immediately snaps back to the channel bottom. i tried to unscrew it with no luck--i expect it is welded into its anchor at the other end.

one question i have right now--could there possibly be an issue besides the truss rod that would cause the symptoms described?

as the thread title says, advice and comments welcomed. thanks y'all!

[yodedude2]

i have xray pics to post soon...i would really like some informed opinions for self-repair tips.

[Andyman001]

The T.R. sits in a curved channel, the wood at the center is thicker from the frets to the rod than at the ends. so when tightening, you are countering the force from the strings.

With yours,the neck is "bulging" instead of "straightening".

I can't think of a reason for it though.

[yodedude2]

here are the xrays:


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should i try a backclamp/heat lamp treatment or go straight for a truss rod replacement? thanks!

[yodedude2]

Originally Posted by Andyman001

The T.R. sits in a curved channel, the wood at the center is thicker from the frets to the rod than at the ends. so when tightening, you are countering the force from the strings.

With yours,the neck is "bulging" instead of "straightening".

I can't think of a reason for it though.

thanks! the way i read your comments, the truss rod should not be straight at rest. this fits with the xray pics as well; it looks like the truss rod is curved without any tension on it at all...i wonder why the neck bulges instead of straightens? is it simply a bad neck and not a bad truss rod? should the neck be steamed into place? or back clamped and heat lamped? or should i simply replace the truss rod? i do not want to replace an existing good truss rod on a bad neck... thanks again.

[yodedude2]

i tried the back clamp/heat lamp treatment and induced a back bow to the neck. i waited a day and reassembled the bass. i gave the truss rod about three 1/4 turns before reassembling the bass. i am using t-i flats and tuning to 'd' standard. at first, the back bow was so pronounced that i had to tune using the notes at the 12 fret; the open strings would not sound.

after 24 hours, the back bow is reduced so that the open strings now sound. the bass is generally playable from the 5th fret on up; on lower frets the notes 'fret out' and do not sound.

i will check it again this evening. in general, it seems to me that the neck moves quite a bit; i assume this means it is not very stable. i wonder if the wood between the truss rod channel and the frets is too thin? again, this neck has a skunk stripe with integrated fretboard; see the first post for a pic.

again, comments and advice welcomed.

[jmorbita]

May I suggest you contact Scott at Birdsong Guitars / SD Curlee ?
I understand he bought the SD Curlee brand and is making these basses again from original specs.
Scott is a great guy to talk with, has always answered every single email I sent and I'm sure he'll be more than delighted to talk over the phone about an SD Curlee bass. He might give you some insight on how the truss rod was originally built.
http://www.sdcurleeusa.com/
http://www.birdsongguitars.com/
good luck with that!

[Rickett Customs]

*edit* As mentioned above.

This type of trussrod is a "Fender" style (for example).

It should be in a curved slot (which would make it appear bent). Otherwise, it wouldn't
really work the way that it was intended.

If you want to take some of the backbow out of it, try pulling the frets, level with a proper radius block (not too much of course, just enough to take a bit of the bend out of the middle). Then when refretting, you can make up some more, when you level the frets.

[SolarMan]

Originally Posted by jmorbita

I understand he bought the SD Curlee brand and is making these basses again from original specs.

Except for the necks - he uses his own formula. (Those SD Curlee necks were never right).

Yes, get in touch with Scotty - I'm sure he has seen plenty of those to know right away.

[yodedude2]

i did get a reply from mr. beckwith to my e-mail. he offered similar advice to mr. rickett above, i.e. plane/level the top of the neck. mr. beckwith also suggested refretting with frets that have a 'wider tang'. i assume this would help stabilize the neck.

i'm sticking with the backclamp/heatlamp/low tension strings tuned to d-standard method for now. we'll see where we stand in a couple of months. it's clear the neck needs help with fret leveling as it stands. the neck has a very mild hump in the 5th-7th fret area, however, it's nothing like it was before. i may be able to save this bass yet!

thanks for the help y'all. i'll leave this here for the next s.d.curlee owner.

[Rickett Customs]

yodedude,
Using frets with a wider tang, could be the other good idea, to introduce more back bow, that's a good call