Setting the blade guides.

A bandsaw blade is held steady by two sets of guides, one above the table and one below. They stop the blade twisting sideways and being pushed backwards when you feed the work. Set well, they make the saw cut straight and help blades last; set badly, they heat the blade, wear the teeth or let the cut wander. They need setting every time you change to a blade of a different width.

What each part does.

• Side guides. A pair of blocks or bearings, one on each side of the blade, that stop it twisting and bending sideways.
• Thrust bearing. A bearing behind the blade that stops it being pushed backwards off the wheels when you feed the work.
• Upper and lower sets. The upper set moves up and down with the guide post; the lower set sits under the table.

Blocks or bearings.

Older and many smaller saws use guide blocks of steel, ceramic or a composite material that the blade runs between. Many others use ball bearings that the blade runs against. Both work when they are set correctly. Blocks wear and need occasionally dressing flat or replacing; bearings must spin freely. Some saws need special inserts or settings for the narrowest blades; check your manual before fitting a 1/8 in (3 mm) blade.

The usual order.

1. Back everything off. Move both side guides and the thrust bearing, above and below the table, away from the blade.
2. Tension and track the blade first; see setting tension and tracking.
3. Set the front-to-back position. Move the side guides forward or back so they support the blade body just behind the gullets. They must never touch the teeth, or they will ruin the set.
4. Set the side clearance. Bring each side guide in until it is just clear of the blade. Many manuals give a gap about the thickness of a piece of paper; use your manual’s figure.
5. Set the thrust bearing just behind the blade, so it doesn’t turn while the saw runs with no work, and only starts turning when you feed.
6. Repeat below the table, then turn the wheel by hand to check that nothing touches.
7. Lower the upper guide to just above the work for every cut.

Signs the guides need attention.

• A ticking or rubbing noise with no work in the saw.
• Blue or polished marks on the blade body, or a hot blade.
• Damaged teeth along one side: the guides are set too far forward.
• A thrust bearing that spins all the time, or is seized and grooved.
• Cuts that wander even with a sharp, well-tensioned blade.