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 Post subject: Neck bow help
PostPosted: Wed Mar 03, 2021 9:56 pm 
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I cut the side profile on my nearly finished Honduras Mahogany neck and got a bow, concave on the fret side.
I’ve never encountered this before. I have made about 40 necks using a stack of old Mahogany.
The neck is flat-sawn. The humidity was around 80% when I cut it four days ago. Today it is 40%.
The off-cut piece is pretty bowed, the middle of the neck is bowed about 1/32”.

I plan to wait to see what happens during the next week or two.
Should I crank the truss rod to near flat, or leave it loose?
Any advice is appreciated.


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 Post subject: Re: Neck bow help
PostPosted: Wed Mar 03, 2021 10:41 pm 
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Brazilian Rosewood
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Instead of cranking the truss rod down, it might be more useful to clamp the fretboard face down on something strong and flat, like the top of a table saw or workbench. Is there more wood to remove from the back of the neck or is it final carved?


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 Post subject: Re: Neck bow help
PostPosted: Thu Mar 04, 2021 12:40 am 
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Have you even carved the neck yet?

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 Post subject: Re: Neck bow help
PostPosted: Thu Mar 04, 2021 10:28 am 
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Barry Daniels wrote:
Instead of cranking the truss rod down, it might be more useful to clamp the fretboard face down on something strong and flat, like the top of a table saw or workbench. Is there more wood to remove from the back of the neck or is it final carved?


I have not carved the neck.

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 Post subject: Re: Neck bow help
PostPosted: Thu Mar 04, 2021 10:29 am 
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Chris Pile wrote:
Have you even carved the neck yet?


I have not carved the neck. Perhaps this will relieve some of the stress?

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 Post subject: Re: Neck bow help
PostPosted: Thu Mar 04, 2021 12:20 pm 
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Brazilian Rosewood
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Definitely do the final carve then see where the neck wants to settle in.



These users thanked the author Barry Daniels for the post: dzsmith (Thu Mar 04, 2021 5:34 pm)
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 Post subject: Re: Neck bow help
PostPosted: Thu Mar 04, 2021 6:44 pm 
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Koa
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you're (obviously) dealing with wood...anytime you start making rips in wood you roll the dice as to what's going to happen...only a 1/32" bow? that's nothing...let this be a lesson about needing to approach final dimensions as opposed to just going for it full tilt and ripping to the final dimension leaving no room for flattening after the woods moves from internal stresses...

the following is a worst case scenario that pretty much isn't going to exist in lutherie: take a `1x8 piece of anything and rip it right down the middle...the odds of both pieces being straight afterwards are about 0...sometimes one side goes insane and the other stays pretty straight...sometimes they both go insane and that's just life (and a lesson about ordering materials close to final dimensions as opposed to ordering stuff and planning to get 2 rips out of it)

sometime back Taylor had a video around detailing how their machines mill up necks by taking multiple passes and slowly getting to the finished product...point being the awareness of movement in wood as you start removing some so take it in stages until you get to a final product...



These users thanked the author Mike_P for the post: dzsmith (Fri Mar 05, 2021 9:31 am)
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 Post subject: Re: Neck bow help
PostPosted: Thu Mar 04, 2021 7:50 pm 
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Quote:
I have not carved the neck. Perhaps this will relieve some of the stress?


Or create new ones. Carve the neck, then we'll see.

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These users thanked the author Chris Pile for the post: dzsmith (Fri Mar 05, 2021 9:30 am)
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 Post subject: Re: Neck bow help
PostPosted: Fri Mar 05, 2021 10:34 am 
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Joined: Fri May 18, 2012 8:35 pm
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Location: Austin, Texas
First name: Dan
Last Name: Smith
City: Round Rock
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Zip/Postal Code: 78681
Country: USA
Focus: Build
Status: Amateur
Thanks guys!
I’ll let it sit for a week with a loose truss rod and let it do it’s thing before carving.
This is the first time I’ve seen this with my Mahogany stash and it frightened me.

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