Saturday, October 6, 2012

Resawing By Hand

Resawing is the technique of ripping boards across their width to make thinner boards. It's useful for making things like drawer sides, box dividers, custom veneers, or slices for bent wood laminations. This is the alternative to planing thicker stock down, which wastes a lot of wood.

This past February I gave a demo on resawing by hand at WoodExpo in Boston, which Justin DiPalma recorded on video. I've edited the raw video down to the interesting parts for The Furniture Project website (recall that WoodExpo is now The Furniture Project).

Here it is on YouTube:



Below are photos from the video. There are three examples of resawing, with both soft and hard woods:
  • resawing a 14" piece of construction-grade 2x6 with a full-size ripsaw;
  • resawing a 5" piece of pine 1x4 into a very thin slice with a Japanese ryoba;
  • resawing an 8" piece of oak 1x4 with the ripsaw.
These pieces took 10.5, 3.5, and 10.5 minutes to do.


First piece, 2x6 with ripsaw. From left: my 26", 6 TPI ripsaw; starting the resaw; progress after flipping the piece a couple times.


About halfway through; down the length to the far corner; opening it up to check the cut surface after doing the other end.

Resawing by hand is definitely work, probably the most laborious operation you can do, so pace yourself and take breaks. But the point is, it's not that hard, it's definitely doable, and it gives you a lot of freedom, because it allows you to work in any thickness. The technique isn't complex, just time-consuming (10 and half minutes to resaw a 14" length of 2x6). It's really just heavy ripping.

You should take 10 minutes to sharpen your saw before any major resawing, then wax it to minimize friction. You should also minimize the amount of wood you're resawing by cutting the stock down to close rough width and length first.

The resulting resawn surface may be pretty rough, but it cleans up quickly with planes. Just be sure to leave enough margin when you mark out the thickness you'll be cutting to allow for that.

As you get better, you'll be able to get multiple slices out of the same piece should you need to do so. That's why I demonstrated the ryoba; I can get 5 slices out of a 3/4" thickness of wood.

Just remember that the bigger piece, the more challenging, and the more chance of things going wrong (like when I tried to resaw a 12" wide piece of mahogany; the saw bowed inside the cut and eventually cut through the middle of the surface). Try some different sizes and different species to learn your limits.


Second piece, pine 1x4. Starting in with the ryoba; halfway after flipping a couple times; comparing the two thicknesses.


Third piece, oak 1x4. Making a starter kerf with a backsaw; working on the second corner; down the length; about halfway through.

To resaw a piece, mark the edge all around, leaving adequate margin in the thickness for cleanup. Start at an angle on a corner, like you're sawing out a tenon cheek; sometimes it helps to make a small starter cut with a backsaw. You can either saw this corner all the way down until you reach the adjacent corner, or just saw down halfway to it, depending on how heavy the going is. Then flip the board and work from that corner.

Once you've made good progress on the second corner, flip the board again and do more from the other side. Do this repeatedly until you pass the halfway point of the length. Then you can switch the board end for end and repeat the process on those corners. Eventually it all meets in the middle.

You'll notice a couple of things. First, every time you start in from an edge, you're cutting a small triangular corner that grows in size and difficulty as you reach the other edge. Second, the existing kerf where you've already cut guides the saw, helping keep it straight.

More frequent flipping makes it easier and keeps it more accurate. If you find it getting off track, flip it immediately and start from the other edge, but pay attention to the exit of the saw. If it's still getting off track, switch to the other end. This gives you a couple of chances to recover from mistakes.

You can also raise and lower the angle of the saw as you work to change how it's cutting. Experiment with it. Lower it all the way to extend the kerf along the length so you can reach the far end. That then creates a starter kerf for working on that end.

This isn't something you'll want to do a lot of, but it's a very valuable skill. You're no longer limited by the thickness of the available stock, and you don't need to waste large amounts of wood planing down for thin pieces.