A board straight from the sawmill or lumber yard is not ready for use in fine woodworking. It may be rough, cupped, twisted, or bowed. Even a board that appears flat may have subtle irregularities that cause problems during joinery and assembly.
Planing is the process of making a board flat, straight, and smooth. It is one of the most fundamental operations in woodworking, and mastering it transforms your work. A properly planed surface is smoother than any sanded surface and actually reflects light differently — a quality visible in the finest furniture.
Before you can use a board, it should be milled through these four steps (known as “S4S” — surfaced four sides):
This order matters. Each step references the previous one. Skipping steps or doing them out of order compounds errors.
Jack plane (No. 5, ~355 mm long):
Jointer plane (No. 7 or No. 8, 510-610 mm long):
Smoothing plane (No. 4 or No. 4½, ~250 mm long):
Block plane (~150 mm long):
Shoulder plane:
A hand plane does not work well out of the box. You must tune it:
Flatten the sole: Place sandpaper (80-grit, then 120, then 220) on a known-flat surface (glass, granite, or a jointed machine bed). With the blade retracted but the lever cap tensioned, rub the plane sole on the sandpaper in a figure-eight pattern. Continue until the entire sole shows an even scratch pattern. This may take 30-60 minutes for a new plane.
Sharpen the blade: This is covered in depth in Chapter 13, but the blade must be razor sharp. A sharp plane blade should be able to shave hair from your forearm.
Set the chip breaker: The chip breaker (cap iron) should sit within 0.5-1 mm of the blade’s edge for smoothing work, or 2-3 mm for rougher work. There must be no gap between the chip breaker and the blade — any gap will jam with shavings.
Adjust the blade: Sight along the sole from the front. Advance the blade until you can barely see it protruding. It should be parallel to the sole (even left to right). Adjust the lateral lever until even.
Check for twist: Place winding sticks on the board and sight across them. If twisted, note which corners are high.
Mark the high spots: Use a straightedge across the board in multiple directions. Mark high areas with pencil.
Plane diagonally: With the jack plane set for a moderate cut, plane diagonally across the board (about 45° to the grain). This prevents the plane from following existing undulations. Work from the high spots toward the low spots.
Plane the other diagonal: Cross the previous strokes at roughly 90° for an even removal pattern.
Check frequently: Use the straightedge and winding sticks after every few strokes. Stop planing when the surface is flat.
Plane with the grain: Once flat, plane with the grain using the jack plane set for a lighter cut. This removes the diagonal plane tracks.
Smooth: Finally, use the smoothing plane with a very fine set, planing with the grain for the final surface.
To create a straight, square edge for a panel glue-up:
Spring joint technique: Intentionally plane a very slight concavity in the middle of the edge. When clamped for glue-up, the clamp pressure in the middle forces the ends together tightly. As the wood dries and shrinks over years, the end-grain areas (which lose moisture faster) are under compression, preventing the joint from opening at the ends.
A jointer (surface planer in some regions) has a long, flat table with a rotating cutter head in the middle. It serves two purposes:
Using a jointer:
Limitations: A jointer can only flatten one face relative to its own table. It cannot make a board a uniform thickness — that is the planer’s job.
A planer has a flat bed and a cutter head above. The board feeds between them, and the cutter head removes material from the top face, making it parallel to the bottom face.
The critical workflow:
Common mistake: Running a cupped or twisted board through the planer without first jointing one face. The feed rollers flatten the board temporarily, but as soon as it exits the planer, it springs back to its warped shape — now it is warped AND thinner. Always joint before you plane.
Tips for clean planer results:
Snipe is a common planer defect: the first and last 50-100 mm of the board are cut slightly deeper, creating a scalloped area at each end.
Cause: The feed rollers only grip the board on one side of the cutter head, allowing the board to tip upward slightly as it enters and exits.
Solutions:
A router plane is a hand tool with a small blade that cuts at a fixed depth relative to the tool’s base. It is invaluable for:
Use it as a final step after roughing with a chisel or router.
A card scraper is a thin, flat piece of steel (about the size of a playing card) with a tiny burr (hook) rolled on its edge. When pushed or pulled across a surface, this burr shaves off a tissue-thin curl of wood.
Why use a scraper instead of a plane?
Preparing a card scraper:
Using a card scraper:
The ultimate goal of planing and surface preparation is a surface that:
The progression:
Many fine woodworkers apply finish directly to a smoothing-planed surface without sanding. The plane produces a surface with a depth and clarity that sanding cannot match — sanding scratches the surface randomly, while a plane cleanly severs the fibers, creating a reflective quality.
Flatten a board: Take a rough, warped board and flatten one face entirely by hand with a jack plane and jointer plane. Verify with winding sticks and a straightedge.
Smooth a surface: After flattening, use a well-tuned smoothing plane to produce a glass-smooth, tear-out-free surface. The shavings should be translucent.
Edge joint two boards: Joint two board edges and test the fit by holding them together toward a light source. You should see no light gaps.
Scraper technique: Practice preparing and using a card scraper on a piece of figured wood (curly maple is a great test). The scraper should produce thin shavings with no tear-out.
Previous Chapter: Advanced Joinery
Next Chapter: Shaping and Routing