Eight Steps for Preparing Lumber for Woodworking Projects

using a benchtop jointer
There are eight steps to preparing lumber at the beginning of the construction phase of a project. Whether you buy rough or surfaced lumber from the mill, the lumber yard, a home center, or a specialty wood store you have to prepare the lumber for use.

The lumber can be "rough cut" from the mill, or "surfaced" lumber that has been smoothed on two, three, or four sides. Regardless of whether or not you buy lumber rough or surfaced, the wood has to be prepared for use. You have to take into account the design size of the pieces required for the project, any grain pattern considerations for the project from the plank we are cutting up, and any warping in the wood.

Rough lumber gives you more thickness to work with when preparing the lumber to eliminate a warp. Rough lumber is usually 1/8th inch (3 mm) to 1/4 inch (6 mm), or more, thicker than surfaced lumber.


Cut the board to rough length

The first cut to make to a board is to slice approximately a 1 inch (25 mm) piece from the end of the board. Look for small cracks, called checks, which may not be visible but could ruin a piece. If not eliminated, checks could continue to propagate in your project piece and eventually split the entire length.

Try to bend the end-cut piece, if you see a crack or it breaks when you bend it, cut another piece. Continue to cut and check pieces until no more cracks are found. you may sometimes have to cut eight inches (200 mm) or more from the end of a board to eliminate the checks. Once that is done cut the pieces you need from the board.

Allow at least one extra inch (25 mm) of length in each of the pieces you are cutting from the plank. Mark the board for the cuts. Use a radial arm saw, table saw, or miter saw to make these oversize cuts.


Flatten the best face of the board

Pick the best face of the board and run that face down across the jointer. You will probably have to make several passes over the jointer because wood is never perfectly flat to begin with. Even surfaced lumber bought at a specialty hardwood store can be warped. Nark the jointed face with an "X" or an "@" in pencil to designate it as the reference face for later layout work.

Note: Do not use a planer to do the flattening on this first side because a planer only mirrors what's on the other side of the board. If the board is warped, it will now be warped the same on both faces.


Flatten one edge of the board

Pick the best edge of the board and run that edge down across the jointer with the reference face flat against the jointer fence. Again, you will probably have to make several passes across the jointer. Before you begin, make sure that the fence is 90o perpendicular to the jointer outfeed bed. Mark the jointed edge with a "V". The point of the "V" faces the reference face. Now you know from a quick glance where your reference face and edge are on the piece.


Flatten the opposite face

Run the board through the planer with the reference face down against the bed (for planers with the cutters on the top side -- most are this way). Make as many passes as needed to get the board to the desired thickness. Do not take off too much -- leave about 1/32 inch (1 mm) extra thickness to allow for removal of the machine marks by hand plane, scraper, or sandpaper.


Cut the opposite edge to width


Run the board through the table saw with the reference edge against the fence. Leave about 1/16 inch extra for jointing and smoothing.


Joint the sawed edge

Run the sawed edge across the jointer to remove the saw marks. This usually takes just one pass (maybe two, if the sawed edge is rough). The jointer should be set for a very thin cut, maybe 1/64th inch. Leave about 1/32nd inch (1 mm) extra width for final removal of machine marks.


Cut the best end square

You choose the best end first, you want to take off only a minimal amount, no more than 1/4th inch (6 mm). Cut the end at 90 degree on the table saw or miter saw.


Cut the opposite to length

Measure and cut to final length on the table saw or miter saw. As before, leave about 1/32nd inch for removal of machine marks and smoothing.

That's it. You should have a perfect board ready for your project.



Tips

  • Allow boards to acclimate in your shop for one to two weeks before you use them. The humidity in the shop is usually different from the place where you bought the lumber. It gives the board a chance to settle down to equilibrium moisture content with the shop. Most of the wood movement and warping the board will do will occur in this one to two week time-frame.
  • Do not use green wood. Green wood has not been dried and therefore has an unusually high moisture content. Besides causing rust to your machinery, green wood is unstable and after preparation will warp in unpredictable ways. Green hardwood usually takes one year per inch of thickness to air dry.
  • Before I prep a board I like to carefully look it over. I look at the grain pattern. I look for features I want to highlight in my projects or avoid, such as knots. I figure out all the pieces I want to make from the board and mark them in chalk or crayon for cutting.
  • Plan to buy at least twenty percent more lumber than your project calls for.

Dressing Lumber





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