Establish one flat face and one square edge before making the opposite surfaces parallel and cutting to length.
A jointer establishes flatness; a planer establishes thickness
A jointer establishes flatness; a planer establishes thickness
Stock is the material a part starts from. Rough lumber may have uneven surfaces or warp. A jointer removes material to establish a flat face. With that face as a reference against a square fence, it can establish a straight edge at 90° to the face.
A thickness planer cuts the upper face relative to the face supported by its bed. With a flat reference face down, it makes the opposite face parallel and brings the board to thickness. Jointing both faces separately does not ensure they are parallel.
Why a planer alone can preserve a bow
Feed rollers can press a bowed board flatter during the cut. When the pressure is released, the board can spring back. Uniform thickness and flatness are different requirements. Specialized fixtures can provide a reference for other methods, but the sequence here assumes an ordinary jointer and thickness planer.
Build reference surfaces in order: face, edge, thickness, width, length; Practice
Build reference surfaces in order: face, edge, thickness, width, length
This is the geometry sequence for preparing rough stock. It assumes enough material remains for the finished dimensions and that the stock fits the equipment. It is not a machine setup guide; use Equipment Operating Procedure and Machine Hazards and Housekeeping for operation.
Face-joint: establish a flat face and mark it as the reference.
Edge-joint: use the reference face to establish one straight edge square to it.
Plane: place the reference face against the planer bed and bring the opposite face parallel to it at the required thickness.
Rip: use the straight reference edge to locate the cut; make the opposite edge parallel at the required width.
Crosscut: establish a square end, then cut the other end to the required length.
Any preliminary breakdown into shorter, oversized blanks comes before final sizing. Leave allowance for the later cuts; an early rough crosscut is not the final crosscut in this sequence.
Try the order on a warped board: what each machine removes or copies; Interactive
Try the order on a warped board: what each machine removes or copies
Pick a board with cup, bow, twist or crook, as defined in Grain and Moisture Movement. Choose the next operation, predict the result, then check it with a straightedge, winding sticks and a square. Try the planer first, then the reference order, and compare. This is reference-surface geometry, not machine operation: see Jointer, Table Saw and Equipment Operating Procedure before using the machines.
Square a warped board. With JavaScript, this card is an interactive board you can machine one operation at a time: pick a cup, bow, twist or crook, predict what the jointer, planer or table saw will do, and check the result with a straightedge, winding sticks and a square. The figures below come from the same model.
The reference order on four warped boards
Each strip starts with a rough board (warp exaggerated to be visible) and applies face-joint, edge-joint, plane, rip and crosscut. Every later step uses a surface an earlier step made true.
Cup board, Joint face, Joint edge, Plane, Rip, Crosscut. Final: face A 0.0 mm out of flat, thickness 19.0 mm, edge A 0.0° off square.Bow board, Joint face, Joint edge, Plane, Rip, Crosscut. Final: face A 0.0 mm out of flat, thickness 19.0 mm, edge A 0.0° off square.Twist board, Joint face, Joint edge, Plane, Rip, Crosscut. Final: face A 0.0 mm out of flat, thickness 19.0 mm, edge A 0.0° off square.Crook board, Joint face, Joint edge, Plane, Rip, Crosscut. Final: face A 0.0 mm out of flat, thickness 19.0 mm, edge A 0.0° off square.
Planer first: thickness becomes even, the cup stays
Cup board, Plane, Joint face, Joint edge, Plane, Rip, Crosscut. Final: face A 0.0 mm out of flat, thickness 13.1–19.0 mm, edge A 0.0° off square.
Worked example (cupped board). The rough board’s face A is 6.2 mm out of flat. In the flexible-board example the planer presses it flat, cuts the top parallel to the pressed underside, and releases it: thickness becomes 19.0 mm, but face A is still 6.2 mm out of flat and face B now copies the cup (6.1 mm). Flattening face A afterwards leaves the board 13.1–19.0 mm thick, short of 19 mm. In the reference order the same board finishes at 19.0 × 110.0 × 520.0 mm with every check at zero within the model’s tolerance.
Cup board: what each step leaves (model mm). Planer: flexible board pressed flat by the rollers.
Order
After
Face A out of flat
Face B out of flat
Thickness
Edge A off square
Planer first
Rough board
6.2
6.1
36.0
6.9°
Planer: face A on the bed, plane to 19 mm
6.2
6.1
19.0
6.9°
Jointer: flatten face A
0.0
6.1
12.9–19.0
0.8°
Jointer: straighten edge A against the fence
0.0
6.1
12.9–19.0
0.0°
Planer: face A on the bed, plane to 19 mm
0.0
6.1
12.9–19.0
0.0°
Table saw: rip to 110 mm, edge A on the fence
0.0
3.4
13.1–19.0
0.0°
Crosscut: square both ends to 520 mm
0.0
3.4
13.1–19.0
0.0°
Reference order
Rough board
6.2
6.1
36.0
6.9°
Jointer: flatten face A
0.0
6.1
29.9–36.0
0.8°
Jointer: straighten edge A against the fence
0.0
6.0
29.9–36.0
0.0°
Planer: face A on the bed, plane to 19 mm
0.0
0.0
19.0
0.0°
Table saw: rip to 110 mm, edge A on the fence
0.0
0.0
19.0
0.0°
Crosscut: square both ends to 520 mm
0.0
0.0
19.0
0.0°
Edge before face. On the twisted board, jointing edge A first and face A second leaves edge A 1.9° out of square: where the twisted face touched the fence, its local angle set the edge angle. Flatten the face first, then use it against the fence.
What the model assumes
Geometry only, in millimetres. The board is a grid of points on its faces, edges and ends. Every cut is a plane or a surface built from straight lines, and a point outside the cut slides inward along the board until it reaches the cut, so no step can add material.
Jointer face: an ideal long, flat table. The board rests on its lowest points; the cut stays parallel to that resting plane and passes continue until the deepest hollow is reached. The pass count shown is an illustrative step, not a depth-of-cut recommendation.
Jointer edge and table-saw rip: the edge rests on its outermost points along a long table or fence, so the cut is straight along the length. The face touching the fence or table beside the cutter sets the edge angle, so a flat face gives a square edge and a twisted face does not.
Planer, flexible-board example: feed-roller pressure is assumed to bend the board until its overall curve lies on the bed; the top is cut parallel to that pressed underside and the warp returns on release. A stiffer board, or one shimmed on a flat sled, can instead keep its resting attitude; switch the planer to the rigid case to compare. Neither case is a rule for every board or planer.
Crosscut: each end is cut perpendicular to face A and edge A near that end, first end just to clean up, second end at the finished length.
Warp amounts (cup 6 mm, bow 14 mm, twist 12 mm, crook 16 mm on a 640 × 150 × 36 mm blank) are deliberately large illustrative values, not measured boards. Machine setup, feed, guards, snipe, tearout, kickback and moisture movement are outside this model.
Check geometry instead of counting machine passes; Checklist
Check geometry instead of counting machine passes
One pass is not proof that a surface is ready. The result of each stage is the reference for the next. Flatness means a surface lies in a plane; parallel faces maintain a constant separation; square surfaces meet at 90°.
Check the reference face for flatness with a straightedge and for twist with winding sticks, a matched pair of sighting bars.
Check the reference edge for straightness and squareness to the face.
Measure thickness at several positions after planing.
Check width, parallel edges, end squareness and final length.
Recheck dimensions and geometry if material removal releases stresses and the board moves.
Stop and reconsider the intended dimensions if flattening would make the board too thin or too narrow. No sequence can recover material already removed. Use How Saws Cut Wood to account for kerf in the width and length layout.
