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 Post subject: overbow vrs. underbow
 Post Posted: Tue May 30, 2006 8:23 am 
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Joined: Thu May 25, 2006 7:54 am
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Location: west virginia
Working on a new 660/12. The strings are too high for my liking and I am contemplating an adjustment to the truss rods. I think that the neck is probably a bit too loose and is succumbing a bit too much to the tension of the strings, thus creating too big a gap between the fretboard and the strings. Is this called an "overbow" or an "underbow?" If I knew which it was, I could follow the procedure in the manual which directs in terms of those names. My gut tells me that what the directions are saying is for me to tighten the nuts (clockwise) an eighth of a turn each (separately, with time in between for the neck to settle) to straigten the neck up and reduce the gap between the fretboard and strings. Help, please.


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 Post subject: Re: overbow vrs. underbow
 Post Posted: Tue May 30, 2006 10:51 am 
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Joined: Thu Sep 22, 2005 1:00 pm
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Location: S.W. Michigan
To check the bow, fret a string at the first and last positions and look around the 10th or so fret and see if there is a gap or if it is pre-touching the fret. If there is a gap, tighten the truss rods. If it touches before the two fretting positions are touching, then there is a backbow and the truss rods need to be loosened. It is advisable to not adjust too much at once (1/4 turn) and to let the neck settle a while before more adjustment. There are more posts about truss rod adjusting so a search would turn them up.


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 Post subject: Re: overbow vrs. underbow
 Post Posted: Tue May 30, 2006 11:17 am 
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Location: Aloha, OR
overbow is convex=( and underbow is concave=). What you want is a very straight playing surface/fingerboard. Then check the heigth of the strings at the top nut. You may want to renotch the string slots, if it's to high for your tastes. Then work on the bridge heigth. All of these adjustments affect the playing action of the guitar. Once you get it set to your liking, then it's time to intonate the instrument. A Rick 12 string can be set up to play very nice, but if you have no experience at this I would suggest you be careful and use common sense when doing these adjustment or you could do more harm than good.


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 Post subject: Re: overbow vrs. underbow
 Post Posted: Wed May 31, 2006 7:48 am 
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Joined: Thu May 25, 2006 7:54 am
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Location: west virginia
Thanks for the responses guys. I did the 1st fret-last fret test and I am sure that there is an underbow in the neck. I just turned one of the truss rod nuts about an eighth of a turn. Took a bit more torque than I had imagined. I'll do other in a few minutes here and post the results when completed.

Again, thanks.


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 Post subject: Re: overbow vrs. underbow
 Post Posted: Wed May 31, 2006 8:01 am 
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Location: S.W. Michigan
Check both low and high strings, and move the appropriate rod accordingly. If only one side was off, you also had a twist. If the neck had no twist and you only move one rod, you will likely end up with a twist. If it is not twisted, move both rods a bit until both low and high strings show a flat neck. Then address the nut if need be, then the bridge height. Always remember to tune up after any of these adjustments as the neck needs to see the correct (tuned) tension for you to measure.


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 Post subject: Re: overbow vrs. underbow
 Post Posted: Wed May 31, 2006 10:40 pm 
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Joined: Mon May 29, 2006 2:32 am
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Location: Columbus, Ohio
I think before I started tweeking my truss rods (which if tweeked the wrong way could really make your guitar feel and sound BAD!), I'd do all I could to adjust the bridge.
Rarely, and I mean rarely is the problem a nut cut wrong, but it IS possible. I'd check EVERYTHING else before attempting to adjust the neck. I agree 100% on using a long straight edge for checking!

Just my 2 cents...

Peace

Dr. Winston O' Boogie


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 Post subject: Re: overbow vrs. underbow
 Post Posted: Thu Jun 01, 2006 12:06 am 
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Joined: Sun Apr 02, 2006 1:00 pm
Posts: 1957
Location: San Bernardino, CA
Yipes!

You guys are scaring me. ...

Ever think about employing the services of a guitar professional?
In the long run, it may be very wise money well spent!


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 Post subject: Re: overbow vrs. underbow
 Post Posted: Thu Jun 01, 2006 12:29 am 
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Joined: Fri Feb 17, 2006 2:00 pm
Posts: 278
Location: Arizona
Quote:
I think before I started tweeking my truss rods (which if tweeked the wrong way could really make your guitar feel and sound BAD!), I'd do all I could to adjust the bridge.
Rarely, and I mean rarely is the problem a nut cut wrong, but it IS possible. I'd check EVERYTHING else before attempting to adjust the neck. I agree 100% on using a long straight edge for checking!

Just my 2 cents...

Peace

Dr. Winston O' Boogie


I don't know...I think I'd go with the advice of John Hall and Dale Fortune and adjust the truss rod first. If one goes no more than a 1/4 turn at a time, and finds out they went the wrong way, it's easily reversible with no harm done.


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 Post subject: Re: overbow vrs. underbow
 Post Posted: Thu Jun 01, 2006 3:56 am 
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Posts: 6
Location: west virginia
Quote:
I think before I started tweeking my truss rods I'd do all I could to adjust the bridge.
Quote:

I did some adjustment to the bridge, but was not sure how much to do. I posted on this (see "bridge adjustment" on this thread) but received no advice. I turned the 4 corner nuts on the bridge a quarter turn each two times (total one-half turn each) and then got nervous about it, not knowing how much these things ought to be turned and feeling also that they seemed to be coming loose.

I think the very minor adjustments I made last night helped some. I retuned and checked action (still not quite as fast as I want) and intonation (Still pretty darn good)

I'll post again tonight after another look. All in all, I've turned the TR adjustment nuts less than a quarter turn each.

Thanks, guys. I really appreciate the advice. This guitar is great sounding and a beauty to behold and I'm loving playing it. I really dont want to screw it up.


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 Post subject: Re: overbow vrs. underbow
 Post Posted: Thu Jun 01, 2006 8:28 am 
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Joined: Thu Sep 22, 2005 1:00 pm
Posts: 1527
Location: S.W. Michigan
Just follow John and Dale's advice. Get the neck straight, get the string height at the first fret how you like it by adjusting the nut groove heights with the correct files, and then adjust the bridge for the string height you want paying attention to fret buzz.

With the bass on the floor and you standing and the headstock in your hands, turning the truss nuts clockwise will tighten the rods and move the headstock end of the neck towards the back of the bass and counter the pull of the string tension. Turning the truss nuts counterclockwise will loosen the rods and allow the string tension to pull the headstock and cause a bow in the neck - fretting at the first and last frets will show a gap in the middle of the string.

It does not take much adjustment of the truss nuts to cause the neck to move. Be judicious but don't be afraid of doing this. Unless the rods are totally loose, turning 1/4 turn is a lot of adjustment. Changing string brands that cause truss rod adjustment will only need minor adjusting. And remember to check for bow at the E string and the G string. (No jokes, please!) You do not want to create a twist.

These instructions are for the 4003 bass. With a 4001, the procedure is the same, but you must move the neck to where you want it and hold it there, then adjust the nuts. If you don't, you will damage the nut threads, the aluminum block at the nuts, and also probably pop the fretboard loose from the neck at the top.

This is a long post and written as simply as I could word it. I do not intend to offend, but to make it easy to understand for all levels of expertise.



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