Resawing Lumber on a Band Saw: Technique and Judgement

Resawing lumber means cutting a board through its thickness to produce two or more thinner boards. The operation turns a thick plank into bookmatched panels, shop-sawn veneer, or several thin boards from stock that would otherwise be planed away. It is a band saw operation because the blade runs vertically and the stock passes through horizontally, so the cut can follow a line over a tall section. The band saw is the common machine that will take a wide board and split it in one pass. A table saw is limited by its blade height, and a circular saw is not suited to the job at all.

The technique rewards preparation more than force. A board that rocks on the table, or that has one face out of flat, will produce a resawn board that is thin at one end and thick at the other. Joint one face and one edge before the cut. The jointed face goes against the fence, the jointed edge goes down on the table. That gives the blade a square reference on two sides, and the resulting boards come off closer to uniform thickness.

Blade choice for resawing

A resaw blade is wide, with few teeth, and those teeth are large. Width keeps the blade from wandering in the cut. Fewer teeth clear the long, stringy chips that resawing produces; a fine-tooth blade loads up, overheats, and burns the stock. A hook-tooth or skip-tooth pattern with a positive rake cuts aggressively and clears waste. A 1/2-inch (13 mm) blade is a reasonable compromise on a small saw; a 3/4-inch (19 mm) or 1-inch (25 mm) blade is better on a saw that will tension it. The blade must be sharp. A dull resaw blade will follow the grain rather than the fence, and no amount of fence adjustment will correct it.

Blade tension matters more here than in curve cutting. The blade must be tight enough that it does not bow away from the cut under the pressure of the stock. Most band saws have a tension indicator; treat it as a guide, not a guarantee. If the blade flutters or the cut wanders despite a square fence, increase tension before changing anything else. Release tension when the saw is idle for long periods; a blade left tight will take a set.

Fence and drift

Drift is the tendency of a band saw blade to cut at a slight angle to the fence. It comes from the set of the teeth, the weld in the blade, and the alignment of the wheels. Every blade drifts a little, and the amount changes when a blade is changed. The fence is set to the blade, not to the table’s miter slot.

A tall fence supports the board through the cut and keeps it square. A single-point fence, which contacts the stock at one point near the teeth, lets the operator steer the board to follow the drift. The tall fence is easier for straight cuts; the single-point fence is more forgiving when the blade drifts. A common approach is a tall fence with a pivot, so the fence can be set to the drift angle and locked. To find the drift angle, mark a straight line on a scrap board, cut halfway along it freehand, stop the saw, and note the angle between the line and the fence. Set the fence to that angle.

The cut

Set the blade guard to just above the height of the stock. The guard should clear the board but leave no room for a hand to pass under it. Feed the board at a steady rate; forcing it will overload the blade and cause it to bow. Use a push block at the end of the cut to keep hands away from the blade and to push the last few inches through. Hands never go in line with the blade, even with a push block. The blade is exposed at the point of cut, and a kickback or a slip will find a hand that is in line with it.

Cut oversize. A resawn board will move as internal stresses release, and a board cut exactly to final thickness will often cup or twist before it can be used. Leave enough to flatten the board after it rests. A common allowance is 1/8 inch (3 mm) or more, depending on the species and the grain. Stack the resawn boards with stickers between them and let them rest for several days before final milling. The movement is not a defect in the technique; it is the wood responding to a new balance of moisture and stress.

Why resawn boards cup

A board carries internal stress from the way it grew and from the way it was dried. Removing material from one face changes the balance of that stress, and the board can cup, bow or twist as it finds a new balance. Uneven moisture across the thickness does the same thing: the drier face shrinks first and pulls the board into a curve. Resawing exposes two new faces to the air, and they do not dry at the same rate. The result is a board that was flat when it came off the saw and is cupped a day later.

Cutting oversize and letting the board rest gives the movement a chance to happen before final milling. If the board cups, joint one face flat again and plane the other parallel. A board that has moved and been re-flattened is more stable than one that was milled to final thickness in one pass. For more on drying and movement, see the wood movement guide.

Bookmatching

Bookmatching means cutting a board into two or more thin boards, opening them like a book, and joining them at the cut edge. The grain mirrors across the joint, producing a symmetrical panel. The technique is used for table tops, cabinet doors, and drawer fronts. The cut must be clean enough that the joint closes without gaps, and the two boards must be flattened after resawing before the joint is cut. A bookmatched panel is only as good as the resawn faces; if the saw leaves a rough surface, the joint will show it.

Resawing methods compared

The mistake most people make

The most common mistake is cutting to final thickness in one pass. The board comes off the saw at the desired dimension, looks flat, and is put aside. A day later it has cupped, and there is no allowance left to flatten it. The mistake happens because the board looks finished at the moment of cutting, and the movement is not visible until later. Resawing is not a finishing operation; it is a rough milling step. Cut oversize, stack with stickers, and let the board rest before final milling. The same principle applies to milling rough lumber: remove material in stages and let the wood settle between them.

A second mistake is forcing the cut. A dull blade or a feed rate that is too fast causes the blade to bow, and the board comes out with a curved face. The cure is a sharp blade, correct tension, and a steady feed. If the saw is working hard, the blade is dull or the teeth are too fine.

Safety

The blade guard should be set just above the stock. At the end of the cut, use a push block to keep hands away from the blade. Never reach around the blade or place hands in line with it. A band saw blade is less likely to kick back than a table saw blade, but it will still cut a hand that is in the wrong place. The push block is not optional.