Why does my saw keep binding and jamming in the cut?

Timber is not inert while you cut it. A board that is supported only at its ends sags the moment the blade weakens its middle. Timber with internal stress, from drying or from growth, springs open or closed as soon as the cut releases it. Damp timber swells. All three do the same thing: they squeeze the slot shut onto the blade.

Safety

Step by step

1. Stop and look at how the work is supported.If the cut line is between two supports, both halves are hanging and the top of the kerf is opening while the bottom closes onto the blade. This single mistake accounts for most binding.
2. Move the supports so they sit either side of the cut, close to it.Four bearers under a board, two each side of the line. For sheet material, a full sheet of rigid insulation on the floor supports everything everywhere and is the easiest answer there is.
3. Let the offcut fall.Never hold the waste side, and never let it hang unsupported off the end of a bench. A held offcut cannot move as the cut opens, so it twists into the blade instead. On a mitre saw, the offcut must be free — trapping it between the fence and a stop is a classic kickback setup.
4. Wedge the kerf in springy timber.For a hand saw in timber that is closing on the blade, drive a thin wedge, a screwdriver or a folded scrap into the top of the kerf well behind the saw. That holds the cut open mechanically. This is standard practice cutting green or stressed timber.
5. Check the blade is not blunt.A blunt blade needs force, and force pushes it out of the vertical, so the plate rubs the kerf wall. That feels exactly like binding. On a circular saw the giveaway is burning as well as sticking.
6. Check the set on a hand saw.The teeth are bent alternately sideways to cut a kerf wider than the plate. Worn, hammered or over-filed teeth lose that set and the plate then rubs on every stroke. On a hardpoint saw the answer is a new saw.
7. Check you are cutting straight.A cut that has wandered off vertical is trying to make the blade travel along a curve it cannot bend to. Back the saw out, restart in the correct plane, and let the saw follow its own kerf rather than steering it.
8. On a circular saw, check the riving knife is present and aligned.The riving knife sits in the kerf directly behind the blade and physically holds it open. If yours has been removed, or bent, or is thinner than the blade's kerf, the saw has lost its main defence against exactly this.

Tips

• The old carpenter's habit of rubbing a candle or a bar of soap along a saw plate genuinely works and leaves nothing that will interfere with glue or finish once the surface is planed or sanded.
• If a powered blade binds, do not pull the saw backwards while it is spinning — that is precisely the movement that throws it.
• Cutting a long rip on a bench: clamp a batten across the board on the keeper side. It stops the board pivoting as the cut progresses.

Common mistakes

• Supporting a board on two trestles and cutting between them — Both halves sag as soon as the cut weakens the middle, and the kerf closes on the blade. It is the classic set-up for a stalled saw or a kickback.
• Removing the riving knife because it fouls a cut — It is the part that holds the kerf open behind the blade. Removing it removes the guard against the exact failure this guide is about.
• Forcing a saw that has started to grip — Force adds energy to a blade that is already being gripped, which is what turns a stall into a kickback.

If it doesn't work