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Making Thin Wood: Resawing Lumber with a Band Saw

by Mark Stephens | February 7th, 2010

Resawing to make thin wood is simple in concept, but it comes with a few challenges as well.

Resawing to make thin wood is simple in concept, but it comes with a few challenges as well.

So you want 1/8″ thick exotic wood, or maybe thinner? Or slice a 3/4″ thick board into some 1/4″ thick pieces? It’s a common question from our customers.  “Can you slice a thicker board into numerous thinner boards?”  It’s a sensible question because it seems like a big waste of wood to plane a 3/4″ thick board to 1/4″.  So, sure, resawing is no problem.

Well . . . sort of.

Check out this great video from The Woodworkers Guild of America about resawing with your band saw.

Looks easy enough, doesn’t it?

Yes.  But resawing introduces a few troubles that you should be aware of when you’re slicing boards to get thin hardwoods, whether they’re exotic or domestic.

1. Results Aren’t 100% Predictable When Resawing

George Vondriska makes two key comments around 2:40 in the video above: “Just in case something goes wrong” and “let’s see how it goes.” Welcome to the world of making thin wood – you just don’t quite know how it’ll come out.

Let’s say you have a board that’s 3/4″ x 10″ x 60″. You’re going to stand the board on edge and push it against a 10″ section of the band saw’s blade, and that’s a lot of wood to cut through at once; a lot of tension, friction, and heat. The likelihood of the blade wandering increases.  And a wandering blade means the saw hogs off more wood leaves you with an even rougher surface.  For this reason, you can get more consistent results when you resaw narrower boards.

A wandering blade can also produce a board that’s miscut – the term “miscut” means you end up with a board, or portion of a board, that’s thinner than what you aimed to get.  With the right fence set up and good sawing technique, it’s still very possible to have miscut pieces; a really dense wood can fight with a resaw blade, so to speak.  Or the tension of your blade can loosen as you work.  Or an abnormality in the work piece can cause the cut to go off course.

So what should you do?  Never resaw? Well, that’s not the answer.  The answer is just be prepared that unexpected things might happen.  Resawing is not a procedure for cutting precisely thick pieces; instead, the best practice is to cut for a slightly thicker piece than you want to end up with and then plane or surface sand to finish it off at the right thickness.  Rule of Thumb: If you want to end up with 1/4″ thick, cut for about 3/8″ just in case.  This is why when we resaw a 3/4″ thick board for 1/4″ pieces in our own mill, we”ll just slice it down the middle and surface the resulting two pieces down to 1/4″.  It’s sensible and practical that way.

To sum up:

  • Band saws produce a cut that’s not very smooth and a little bit wavy; and the waves get more pronounced with denser woods.
  • Resawing narrower boards is easier than wider boards
  • For getting a particular finished thickness, cut about 1/8″ thicker (not including the kerf)  than your desired finished thickness and plane or surface sand to the finished thickness

2. Thin Resawn Wood Has Trouble Staying Flat

Take that 3/4″ x 10″ x 60″ board again.  Let’s say it’s a quality kiln dried board, perhaps 9% moisture content.  In any board, the moisture content is concentrated in the middle of it.  So when you resaw that board into two pieces, you now have two pieces that have an imbalance in the water content location of each one: in short, one face of the newly resawn boards is dry, the other has the bulk of the moisture content (the side that used to be the middle of your original board).

And then that side will start to dry.  The wood fibers will shrink on one side of the board. The thin board will cup. There’s no getting around this fact.  Again, the trick is to learn how to work with this, and react properly to wood movement.

It’s important to realize that cupped boards aren’t hopelessly destroyed.  You just have to re-establish the moisture equality on both sides of the wood (for which there are a number of techniques.

Here’s a nice quote from Good Woodworking Magazine:

Ben Plewes says in “How does Wood Work?” from Good Woodworking Magazine:

There is a general misconception that once wood has been seasoned you don’t need to worry about its moisture content anymore. If only life were that straightforward! Wood continues to expand and contract after the initial drying process is complete. In fact wood, even with a synthetic finish applied, will continually adapt to the ambient moisture level that surrounds it. It’s a slow process so you’re not going to see your wood move the minute you open a window but it will move over a period of weeks to match the average conditions around it.

So if you’ve given resawing a try with your bandsaw and ended up with cupped boards, don’t let that fool you into thinking something went wrong.  It’s not that the wood was of low quality or that your saw did a poor job, or that you don’t have good technique.

It’s just what happens with thin resawn wood.

Woodworkers Source Offers Custom Cutting

Resawing services are available at all Woodworkers Source stores.  Call or come by when you have a board you need resawn into thinner pieces.

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This entry was posted on Sunday, February 7th, 2010 at 6:12 pm and is filed under Tips and Tricks, Woodworking 101. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.

  • george

    using a table saw to slice thin stock you can go wider than 5 1/2 inches. try 8″ which will leave a space of 2 1/2″ then use a pruning saw to remove the remaing wood slice.

  • DEnnis Russell

    I had some thick Sycamore logs that were slasb sawn, I needed quarter sawn, too late I got what I got, I tried to resaw on severtal different large bandsaws, a total failure, my skjills arent very good on this although I have read different articles on how to, to no avail it just doesnt do well I expert could saw this stuff for me but there arent any here in Arizona that I know of. so now I have some dried out sycamore laying undr my work bench, might as well cut it up for fire wood, I was going to make guitar backs and sides with this wood…………………….D

  • Len

    Thanks for the nice article. Two thoughts:

    1. You say “… there are a number of techniques…” for restoring the moisture equality in cupped boards, but you don’t sya what they are. Can you add that information or maybe a link to resources?

    2. I don’t own a bandsaw. Can you add any tips and techniques for resawing on a table saw. I’ve had good results doing this on a 10″ saw with boards up to 5 1/2″ wide, but would like to know if there are any special techniques I sould know about.

    • John

      Before I owned a bandsaw I would resaw on my table saw. To resaw boards wider than 5 1/2″ I would use a handsaw to cut the middle portion of the board after running the blade as high as I could.

    • Anonymous

      I, too, would like information or link “for restoring the moisture equality in cupped boards”. This happens to me all too often, particularly in my garage workshop in Maine in the winter when the humidity might be 15% on a wet day. Right now I have a couple of pieces of 3/8″ thick canary that are cupped too badly to be used as box sides. I’ve had one sitting convex side up in the sun now for a month but there has been no change.

      Jim

      • jghodd

        I ran into this problem when cutting bolivian rosewood (morado) for guitar backs and sides. In fact, the wood warped within minutes of being resawn. I could’ve wept. However, after calming down and doing a bit of research, I was able to successfully re-flatten my pieces and have since used them for their original purpose. To do this, first cut yourself some boards, all of the same size, and make sure they’re somewhat impervious to warping themselves. I used 3/4″ fiber board, cut to 10″ x 24″ for my purposes. You’re going to end up stacking these boards, so make sure you cut enough to have a bottom and top board. Once you have your stacking boards cut and ready, wet your warped/cupped pieces on both sides – I used a spray bottle, then spread the water around evenly, making sure to add more wherever it got soaked up more quickly than other areas. Once the pieces are evenly wet, place the wet pieces between the stacking boards, stacking them vertically as you go, with the last stacking board on top – like a tall sandwich, or a big mac with lots of beef patties. Now, you need to apply a LOT of pressure, evenly, to your stack. I used 8 J-clamps – 3 down each side and one on each end. You can also pile something really heavy on top if that’s more convenient – it’ll need to be a couple of hundred pounds. Final step – wait. Give it a couple of weeks, or longer if you can afford the time. You will be pleased with the results. The lesson I learned was to sandwich and clamp everything I cut if I valued it.