Using a handheld belt sander.

A belt sander removes wood faster than any other sander you can hold, which is exactly why it can ruin a surface in seconds. Most gouges, dips and rounded edges come from a few habits: tilting the sander, holding it still, and pressing too hard. Get those right and it flattens a tabletop or strips a door quickly and cleanly.

Before you start.

• The right belt, in the size documented for your sander, fitted with the arrow pointing the way the belt runs. Check the tracking.
• The right grit. Start only as coarse as you need; see grits and abrasives.
• Secure the work. A belt sander pulls the work towards you as it runs. Clamp it, or butt it against a stop on the bench.
• Clear the cable behind you, away from the belt.

The technique.

1. Start it in the air. Switch on before the belt touches the work and let it reach full speed.
2. Land it flat. Lower the sander so the whole platen touches at once, heel and toe together. Landing on the front or back roller digs a dip.
3. Keep it moving. Move steadily along the work with the grain, overlapping each pass by about half the belt width. Never let it stand still.
4. Let the weight do it. The sander’s own weight is usually enough pressure. Pressing harder heats the belt, clogs it and makes the sander dig in.
5. Watch the edges. Don’t let more than about a third of the platen overhang an edge, or the sander tips and rounds it over.
6. Lift it off running. Lift the sander clear of the work before you switch off.

Sanding across the grain.

For fast flattening, such as levelling glued-up boards, you can sand diagonally across the grain with a coarse belt, then work along the grain with the same grit to remove the cross-scratches before moving to a finer grit. Finish every grit with the grain.

Moving through the grits.

Pencil a few light lines across the surface before each grit. When they have just disappeared everywhere, that grit has done its job; move to the next. Skip no more than one grit at a time, so each one only has to remove the scratches of the one before.

Paint and old finishes.

Coarse, open-coat belts clog less on paint. Old paint can contain lead; if you are unsure what you are sanding, find out before you start and follow your local safety advice.