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PostPosted: Fri Nov 21, 2008 12:19 pm 
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Cocobolo
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I'm building an LMI dreadnaught kit and last night I glued on the fretboard. I fretted the board before gluing it on. The truss is LMI's standard two-way rod. I put a dab of CA on each end of the rod(part that acts as the nut) to secure it in the channel. I glued a spurce shim to the bar stock then scraped it flush with the neck surface, then glued on the fretboard and tried not to get glue on the truss rod shim but I know a little did. Anyway I thought once I glued on the board I could recheck the neck angle and then level and dress the frets. I put the neck on the guitar and when I was checking things out I noticed there is a slight back bow to the neck. I thought with the two way rod I could just turn it counter clockwise and straighten the neck out but it starts getting pretty tight after half a turn or so and the neck still isn't straight. I didn't want to keep turning for fear of destroying something.

So I'm not sure what to do. Does it sound like I screwed something up? Maybe I can level the frets after it's been strung up awhile but it would be nice to check the neck angle and make sure nothing's wrong before the guitar is finished. I'm lost :? I could use some help for sure.

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PostPosted: Fri Nov 21, 2008 12:57 pm 
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I did some more checking at it appears that the neck is straight and it's only the FB extension that's bowed(checked with straight edge). I guess the question remains does it sound like something is wrong with the truss rod? Should it be as easy to adjust as if the guitar were strung up?

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PostPosted: Fri Nov 21, 2008 1:30 pm 
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Jeremy,

I think you're OK. If the frets were a bit tight going into the fretboard, the fb would possibly get a backbow, which could transfer to the neck after it was glued up. The backbow in you fb extension would tend to confirm this. Another factor might have been using a water-based glue, which could have swelled the wood, also contributing to backbow.

Necks often take a little time to settle, so having it appear straighter after some time has passed can be expected.

In the future, it could help if you can help the truss rod along by creative clamping with a beam to straighten the neck a bit before adjusting the TR, so the TR doesn't have to do the straightening, but rather holds the shape after you straighten the neck with clamping. This would only be needed if the TR needed a lot of adjustment like it did here. Good thing you stopped when you did.

If it's strung up, that would help correct backbow, but not the normal bowing. You do want the neck as straight as possible to level the frets.

Post pics when you're done!

Pat

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PostPosted: Fri Nov 21, 2008 1:47 pm 
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There are folks and factories that fret before gluing on the fretboard. If that is what works for them then fantastic. For me, I find that I usually have to level the fretboard somewhat after the fretboard has been attached. I am a proponent of fretting after the fretboard has been attached for this reason. If your fretboard is level then after fretting only a light dusting with a straightedge and sandpaper is all it takes to level the frets and the re-crowning step is quick and easy.
Something else I like to do is wait a week or two after the fretboard is attached and the neck is carved before leveling the fretboard. You will be amazed at how often you need to re level it because the neck has "settled in".


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PostPosted: Fri Nov 21, 2008 1:53 pm 
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Thanks Pat. I think I'll go ahead and level the frets, then recheck the neck angle.

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PostPosted: Fri Nov 21, 2008 2:04 pm 
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Robbie thanks for the tip on waiting for the neck to settle. Maybe next time I'll try fretting after attaching the FB.

And Pat you were right about the frets causing a bow in the FB. I noticed that before I glued it on but it took so little pressure to straighten it out I didn't even consider that might it cause a bow in the neck, but neck is straight it was just the curve of the extension that was throwing me off.

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PostPosted: Fri Nov 21, 2008 5:04 pm 
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Robbie O'Brien wrote:
There are folks and factories that fret before gluing on the fretboard. If that is what works for them then fantastic. For me, I find that I usually have to level the fretboard somewhat after the fretboard has been attached. I am a proponent of fretting after the fretboard has been attached for this reason. If your fretboard is level then after fretting only a light dusting with a straightedge and sandpaper is all it takes to level the frets and the re-crowning step is quick and easy.
Something else I like to do is wait a week or two after the fretboard is attached and the neck is carved before leveling the fretboard. You will be amazed at how often you need to re level it because the neck has "settled in".


hear hear!!!!


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PostPosted: Fri Nov 21, 2008 5:10 pm 
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Jeremy Douglas wrote:
Robbie thanks for the tip on waiting for the neck to settle. Maybe next time I'll try fretting after attaching the FB.

And Pat you were right about the frets causing a bow in the FB. I noticed that before I glued it on but it took so little pressure to straighten it out I didn't even consider that might it cause a bow in the neck, but neck is straight it was just the curve of the extension that was throwing me off.


Even if you do not fret pre installation the fretboard extension will want to sag just a tad after glue up. Not a biggie either case. i am like Robbie though. I almost always find I need to re-level the fret board a tad after installation so I don't fret till I check and correct level after installing the neck/fretboard permanently on the guitar. Yes this means i have to do the fret work carefully to avoid finish damage but with a thin chip board protector that is not a problem.


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PostPosted: Fri Nov 21, 2008 7:42 pm 
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If I recall correctly, Mario, or as he is more commonly known here as 'Grumpy,' also frets the board before gluing to the neck. What he and some others have done is, after fretting, flex the board inward - bring the first fret toward the last - to take the spring out of the FB before gluing. It will lay flat. Then glue to the neck with non-water based adhesive, aka epoxy.

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PostPosted: Fri Nov 21, 2008 8:37 pm 
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Steve Walden wrote:
If I recall correctly, Mario, or as he is more commonly known here as 'Grumpy,' also frets the board before gluing to the neck. What he and some others have done is, after fretting, flex the board inward - bring the first fret toward the last - to take the spring out of the FB before gluing. It will lay flat. Then glue to the neck with non-water based adhesive, aka epoxy.


I have done exactly as Grumpy suggested and Steve W. repeats here. It worked for me, too.


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PostPosted: Fri Nov 21, 2008 9:43 pm 
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You mean simply take it in your hands and flex it once and that takes the bow out? Or do you have to leave it clamped for awhile or something else?

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PostPosted: Sat Nov 22, 2008 4:36 pm 
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From what I remember from the discussion - you flex the FB as many times as it takes. Just be careful not to overdo it so as to loosen the frets. I don't think he clamped it.

I will try to find the discussion in the archives and post the link.

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PostPosted: Sat Nov 22, 2008 4:49 pm 
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OK, try this link to the archives.....................

http://www.luthiersforum.com/forum/viewtopic.php?f=10102&t=15262&p=217808&hilit=fret#p217808

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PostPosted: Sat Nov 22, 2008 7:29 pm 
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The fretboard will take on a back bow when fretted so what I do is clamp the neck to a vise, or a drill press table and put something like a broomstick at the heel of the neck and either raise the broomstick or lower the table (a drill press table is great since you can raise/lower it at will) until the neck takes on an underbow. Then glue the fretboard in at this position and the backbow and underbow will cancel each other resulting in a straight neck with a loose truss rod.

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PostPosted: Sat Nov 22, 2008 8:51 pm 
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Thanks for the link Steve, that was a good thread.

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PostPosted: Wed Nov 26, 2008 12:12 am 
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I learned a lot from this thread and also from the thread at the link provided. Thanks!!!

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