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Bowed Wood Dilema


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I have a nice piece of flame maple measuring about 42 in X 12 in X 1.5 in and am planning on making a neck and maybe a bookmatched top later. The problem is there is a slight bow in the wood, sagging somewhere near the middle. My dad suggested screwing the board to a known flat slab that was slightly longer than the maple and run it through the planer. After a couple of passes showing no improvement, he thought maybe if we stuck a thin shim under the bow in the middle, it would keep the planer from pushing down on the middle of the board and thus would give us a flat top to work with from there.

Is this the best way to get a flat surface? What methods have you guys used if you've run into the same conundrum?

Thanks and Merry Christmas to all.

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I have a nice piece of flame maple measuring about 42 in X 12 in X 1.5 in and am planning on making a neck and maybe a bookmatched top later. The problem is there is a slight bow in the wood, sagging somewhere near the middle. My dad suggested screwing the board to a known flat slab that was slightly longer than the maple and run it through the planer. After a couple of passes showing no improvement, he thought maybe if we stuck a thin shim under the bow in the middle, it would keep the planer from pushing down on the middle of the board and thus would give us a flat top to work with from there.

Is this the best way to get a flat surface? What methods have you guys used if you've run into the same conundrum?

Thanks and Merry Christmas to all.

The only way I think it could be done properly is face-jointing one face most likely the one that's not concave. It's 12" wide and most people wouldn't have access to a jointer that big. What you could do is do it with a router it would take a while though. you could attach it to a flat surface and set up 2 sticks taller than the maple by a little bit at least and attach a longer piece of wood to your router base (doublestick tape) then rout away until everything is routed. Planers will only work good if one face of the wood your planing is flat since it will copy imperfections into the other side that's why you should face-joint everything you put through it if possible.

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The only way I think it could be done properly is face-jointing one face most likely the one that's not concave. It's 12" wide and most people wouldn't have access to a jointer that big. What you could do is do it with a router it would take a while though. you could attach it to a flat surface and set up 2 sticks taller than the maple by a little bit at least and attach a longer piece of wood to your router base (doublestick tape) then rout away until everything is routed. Planers will only work good if one face of the wood your planing is flat since it will copy imperfections into the other side that's why you should face-joint everything you put through it if possible.

+1. Use the planing jig.

How bowed is your wood? (when measure against a straight edge) I've had bad experiences with bowing neck wood, so even if you get it straight, let is sit a while to make sure it doesn't bow again....

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I have never met a piece of wood which is perfect. Yes you can buy a perfect piece but it may not stay that way. Screwing a board to anything is useless, unless you steam heat it first and loosen the fibers. At 1.5" you are not going to change that board even using extreme measures.

The general process is called milling a piece of wood or in easy terms making it square before you use it. Given the size of the piece you bought, unless the bow is severe, I don't see any issues. Mark out the neck pieces in different parts of the board and see how bad the bow is rather than looking at the whole board as a problem. Top plates are never 3/4" so I don't see any issues there.

I am not sure why some people would not use a piece of wood which is bowed, to me it says the wood has settled and is more stable. Offsetting grain direction in a laminated neck will also add additional stability to the project so look to cut mirror images out of the board.

Necklayup.jpg

Notice the grain direction is opposite, can also be reversed. I use this method when using flat sawn boards.

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I have never met a piece of wood which is perfect. Yes you can buy a perfect piece but it may not stay that way. Screwing a board to anything is useless, unless you steam heat it first and loosen the fibers. At 1.5" you are not going to change that board even using extreme measures.

The general process is called milling a piece of wood or in easy terms making it square before you use it. Given the size of the piece you bought, unless the bow is severe, I don't see any issues. Mark out the neck pieces in different parts of the board and see how bad the bow is rather than looking at the whole board as a problem. Top plates are never 3/4" so I don't see any issues there.

I am not sure why some people would not use a piece of wood which is bowed, to me it says the wood has settled and is more stable. Offsetting grain direction in a laminated neck will also add additional stability to the project so look to cut mirror images out of the board.

Necklayup.jpg

Notice the grain direction is opposite, can also be reversed. I use this method when using flat sawn boards.

Or maybe a jointer is what you need, a planer does both ends and is for thicknessing I think.

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I've used the shimming method before on large pieces that cannot go through the jointer. If you want to use this method then you are going backwards. First shim the ends and put the bow down. Take small passes until reaching flat. Then flip the board and make a pass. Continue flipping board each pass and take off equal amounts to balance the board. This in no way will guarantee success. but it is the correct way to use a planner to accomplish this. I would look more at cutting the board to shorter lengths as required for the job as dictated by the neck you want, as well as maybe cutting those into 3" widths and using a sled on a table saw to true up the faces or at least one and then run trough a planer. Then do a lam glue up. I agree with WSpoke, look at the board not as a whole. but as the individual parts and you will see that it is less of a problem.

Just my .02cents

MK

Edited by MiKro
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With a straight edge laying on it's surface, there may be an 1/8" gap somewhere near the center. I will have to take a closer look to see--as some of you suggested--whether cutting it will give me a straighter neck section.

A couple of things since my first post:

-the board is narrow enough to go through the planer, so that's not an issue.

-I want a single piece neck so the laminating is not an option (unless it turns out to be an emergency option).

thanks for the responses and advice guys.

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With a straight edge laying on it's surface, there may be an 1/8" gap somewhere near the center. I will have to take a closer look to see--as some of you suggested--whether cutting it will give me a straighter neck section.

A couple of things since my first post:

-the board is narrow enough to go through the planer, so that's not an issue.

-I want a single piece neck so the laminating is not an option (unless it turns out to be an emergency option).

thanks for the responses and advice guys.

People laminate through necks all the time. With 1.5" it may be a strech, hopefully you have cheecked your plans.

Also 1/8" bow in 40" is nothing. At least from the the stores I visit.

Good luck.

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You should also cut the wood close to the dimensions you will be using then mill the wood. You will lose a lot of material trying to surface a full length board with a bow than if you cut it to appropriate pieces for your parts. If you only have 1/8" bow in 40", it is not too bad. When you cut it down to say 21-24" for a bookmatched top billet, the amount of milling should be very slight. Use a jig to allow you to keep the reference surface for your milling if your infeed and outfeed tables are too small to reference the whole piece. I would opt for a jointer for your neck stock. I usually only care about one true surface(the back of the neck I ruff profile and shape, I use the surface the fretboard is attached to as my true reference surface).

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