Get a Circular Saw Cutting Square Again by Setting Its Bevel Stop to True Zero

The Problem

A circular saw's bevel scale is a pointer and a stop, and neither is a measurement. The stop is set at the factory, and it moves — a drop, a hard year in a van, or a saw that was never right out of the box. The gauge still reads zero, so nothing looks wrong.

What you get is a cut that's a degree or two off square through the thickness of the stock. On a 2x it's invisible until two pieces meet and the joint shows a wedge of daylight. On sheet goods being edge-joined it's worse, because the error doubles at every seam.

The Technique

1. Unplug the saw or pull the battery. You'll be rotating the blade by hand.
2. Set the bevel to zero and lock it.
3. Retract the guard and stand a square against the blade plate and the base. Register on the blade's flat body, not on a tooth — teeth are set outward and will hold the square off the plate.
4. Sight along the join for light. The creator's check is exactly this: tight at the bottom but light showing at the top means the blade is leaning, and that gap is your error.
5. Find the bevel stop's set screw at the pivot. Turn it in small increments and re-check the square each time. As it goes in, it pushes the stop over and takes the lean out.
6. Once no light shows top or bottom, check that the bevel cursor still points at zero. If it doesn't, move the cursor to match the blade — the blade is the truth, the scale is a label.
7. Rotate the blade a half turn and re-check on the same tooth position, to be sure you weren't reading a warped blade.