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Advice needed on a neck set
http://www-.luthiersforum.com/forum/viewtopic.php?f=10102&t=2844		 Page 1 of 1
Author:  JJ Donohue [ Tue Aug 16, 2005 2:43 am ]
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I'm in the final stages of setting a bolt on neck to a parlor guitar. The angle of the FB produces a clearance of .100" over the bridge (with frets installed) and the cheeks are now flush to the body...so I belive I'm OK there.

The issue I'm having is with neck yaw. When I bolt down the neck it shifts slightly to the treble side and the corners of the FB are a bit assymetrical at the rosette. When I run a center down the FB and extend it to the bridge, the center of the bridge is about .100" off to the treble side.

My question...what can I do to get it perfectly centered to the bridge without changing the other values? TIA JJ Donohue38580.4909953704
Author:  JBreault [ Tue Aug 16, 2005 2:54 am ]
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How about a thin shim on the treble side. Just in the mortise.
Author:  John How [ Tue Aug 16, 2005 2:59 am ]
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It would seem that you need to remove a slight amount of wood from the treble side of the heel to move the fingerboard back to center. I would use the old sandpaper floss method myself and if it increases the neck angle just a little, the better so you'll get just a bit more exposed saddle. I like 1/8" or slightly more of saddle so that if the top belly's a little you have some saddle to make adjustments with, otherwise your down to the bridge with nowhere to go. If you use the sandpaper floss method, check your progress often and you may have to do both sides of the heel to keep both in the proper angle although less on the bass side. Also keep an eye on the heel cap if it's on as you have to keep it in line with the sides of the heel.
Author:  LanceK [ Tue Aug 16, 2005 3:06 am ]
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JJ, I Had this happen once, check to make sure that there is NOTHING causing the neck to push to one side, for me is was a drop of dried glue where the fretboard meets the neck, at the tennon end, right at the joint - every time I tightened it up, it tilted! After chasing that bugger down and chipping it off - it went on perfect.
Author:  JJ Donohue [ Tue Aug 16, 2005 3:14 am ]
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Thanks guys...I can't believe the quick response!

Great ideas...it'll be refreshing to have a few ideas for a renewed approach.

I'll keep you posted...a cyber beer to the idea that causes it to shift into place...could be 3 so far!
Author:  John How [ Tue Aug 16, 2005 3:26 am ]
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JJ, when you torque to bolt down, does the cheek pull away from the sides?
Author:  Pwoolson [ Tue Aug 16, 2005 3:30 am ]
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JJ, if Lance's idea doesn't work (ie there isn't anything hanging the neck up) you might try to drag a piece of carbon paper through to see if there are any high spots where they shouldn't be. Sometimes those can cause all sorts of problems. If everything is good there, you are best to floss and I would recomend using 22o or finer. It might be slow going but you won't change anything (angle wise) too quickly.
If I have only one cheek to work on I'll make 5 pulls on that one cheek and then one pull the goes around through the healcap and stops right at the far corner of the healcap. This way I'm not touching the other cheek. Good luck.
Author:  JJ Donohue [ Tue Aug 16, 2005 3:32 am ]
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John...Once the bolts are tightened both cheeks are flush to the body. I kept doing the sanpaper flossing on both sides until I was able to accomplish that.

Where I believe I made an error was in not watching what was happening to the centerline of the FB as closely as I will from now on!
Author:  crazymanmichael [ Tue Aug 16, 2005 4:34 am ]
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have you strung it up yet? depending on how much the top rises under string tension you are looking at a saddle height of 0.225 or more which is a bit on the high side.
Author:  JJ Donohue [ Tue Aug 16, 2005 4:58 am ]
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Crazyman...I haven't strung it yet. Once I have the neck properly set I'll glue down the bridge. I have it taped in position for measuring purposes. C&N say to have airspace of 1/64 to 1/16 over a fretted FB. I have .100 now and I haven't leveled the frets yet. Once I glue down the FB and level the frets, I should be within the C&N tolerance.

BTW, I'm curious as to how you predict a saddle height of .225 or more?
Author:  crazymanmichael [ Tue Aug 16, 2005 10:25 am ]
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straight edge(extended fretboard level) 0.10 above bridge + rule of thumb minimum saddle height of 0.125 above the extended fretboard level = 0.225 saddle above the bridge. this would vary with the action height you want and the degree of rise of the top under string tension.
Author:  Michael Dale Payne [ Wed Aug 17, 2005 2:13 am ]
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When I set my necks I do it prior to freting, I set the neck so the fretboard plane is 3/64" to 5/32" proud of the bridge height. I level the frets after instalation to leave the fret plane 7/64" to 1/8" proud of bridge. Hope I was clear enough to understand
Author:  JJ Donohue [ Wed Aug 17, 2005 3:05 am ]
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Update...

All it took was a lot more flossing on the treble side and it finally shifted into place. Thanks all for the help.
Author:  Michael Dale Payne [ Wed Aug 17, 2005 4:27 am ]
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If it makes you fell any better I had two this year that I thought I was never going to get the yaw correct on. after giving up for the night and starting fresh the next evening, 10 min into it, they fell right in place. I think I may over work the opposing side in inadvertently and cause myself more work
Author:  Dennis Leahy [ Wed Aug 17, 2005 1:51 pm ]
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You know, when I saw Harry Fleishman's (sp?) take on an adjustable neck, I wondered why there would be a need for a yaw adjustment. Now, I think I'm getting a clue.

Good save, JJ!

Dennis
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