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What “straight” means for a timber edge
A board edge is ready for a joint when it is straight along its length and square to the face. A jointer plane makes that easier, but it is not essential. A shorter bench plane, a shooting board, or careful work with a jack plane can all get there. The best choice depends on board length, how much material you need to remove, and how fussy the joint will be.
For a typical glue-up, aim for no visible gaps when the edges are held together under light hand pressure. Check the edge against a reliable straightedge, or bring the two boards together and look for gaps against a light source. A perfectly straight edge is useful; an edge that is also square matters just as much. A plane can make an edge straight but leave it leaning, which produces a poor joint.
Choose a plane and set up the board
A No. 5-size jack plane is a practical all-round choice. It is long enough to bridge small hollows, yet manageable for roughing and truing. A shorter smoothing plane can finish a board that is already close, but it follows hollows more readily. A longer plane helps on long edges, though it costs more and takes more effort to control. If you are buying one plane for general bench work, compare a No. 5 bench plane with a longer jointer before paying extra for length.
Clamp the board on its face with the edge projecting just enough for the plane to clear the bench. Support long stock near both ends and add support in the middle if it sags. Mark the edge with pencil crosshatching; the marks show where the plane has cut. Set the blade for a fine shaving when truing. For fast stock removal, a more open setting can help, but a deep cut is harder to control and may tear out the grain.
Check that the plane iron is sharp and the cap iron is seated securely. A dull edge often crushes fibers or takes inconsistent shavings, making it harder to judge progress. If the board has reversing grain, reduce the cut and plane in the direction that leaves a clean surface. If neither direction works, a finely set plane or scraper may be needed for the last passes.
Plane the edge in stages
First inspect the edge with a straightedge. Mark any high spots and note whether the board is bowed, hollow, or twisted. On a long edge, use a straightedge longer than the board if available; a short ruler can miss a gentle curve. A pair of winding sticks—two straight, parallel sticks placed across the face near opposite ends—helps reveal twist. You can make them from straight scraps, so buying a dedicated set is not necessary for occasional work.
If the edge is rough or noticeably out of line, start with controlled strokes over the high areas. Keep the plane sole flat and use both hands: pressure near the front at the start of a stroke, then shift pressure toward the rear as the plane exits. Avoid rocking the plane sideways. Check often rather than trying to correct the whole edge in one long pass.
As the edge approaches straight, use longer strokes that overlap. A jack plane can still do this well, but keep the blade cut fine. On a short board, it may be enough to work the full length with the plane. On a long board, a longer sole makes it easier to bridge small hollows. A straightedge for checking a board edge is useful, though a known-straight metal rule or carefully checked shop-made stick may be adequate for noncritical work.
Test for square with a reliable try square at several points along the edge, not just at one end. If the edge leans, correct it with light strokes on the high side, checking frequently. Don’t try to fix a large out-of-square error with one heavy pass; the plane can roll and create a tapered edge. Pencil marks across the edge also help show whether you are removing material evenly.
Ways to work without a jointer plane
| Method | Best for | Trade-off |
|---|---|---|
| No. 5 jack plane | General bench work and boards of moderate length | Versatile, but demands frequent checking on long edges |
| Smoothing plane | Short edges already close to straight | Easy to control, but can follow a long hollow |
| Shooting board with a bench plane | Short stock and accurate square edges | Good control, but the board limits work length |
| Hand plane with a long straightedge | Long edges where a jointer plane is unavailable | Works well, but relies on careful marking and checking |
A shooting board guides the plane on its side and is particularly useful for short pieces, such as trim or shelf parts. It is not a substitute for a long sole on a long board, but it can give a square edge with less tendency to tilt. For occasional work, a homemade shooting board is often enough; a shooting board is worth considering if you routinely plane short ends or narrow parts.
Check the fit before calling it done
Bring the prepared edge against its mating board without forcing it. A small gap at the middle usually means a hollow; a gap near one end can indicate a bow or a poor fit between boards. If the gap is slight, pencil the high area and take a few light strokes there, then retest. Keep the plane moving along the edge rather than digging into one spot, which can create a local hollow.
For a glue-up, a hairline gap that closes with moderate clamp pressure may be acceptable, but don’t rely on heavy clamps to pull a badly shaped joint together. Excessive pressure can bow panels or squeeze out too much glue. If the edge is very long, the timber is unstable, or the joint must be highly accurate, a jointer plane or powered jointer may save time. For shorter boards and occasional projects, a sharp jack plane, a square, and repeated checks are usually the cheaper and perfectly workable route.