Rule 7 of 31 · Chapter II — Measure and Mark

Mark the waste side clearly

Why this rule exists

A pencil line has width, and which edge of it you cut to decides whether your part is right or a sixteenth off. Multiply that little ambiguity across a project and nothing fits. Marking the waste with a clear scribble tells your future self, mid-cut and slightly distracted, exactly where the blade belongs. It's the cheapest insurance in the shop, and it's saved me from countless parts cut a whisker to the wrong side of the line.

In practice

As soon as you draw a cut line, put a big X or squiggle on the waste side of it. Line the blade up to eat the line or ride just outside it, keeping your finished part full and true. Stay consistent about cutting to the same side of every line so your kerf allowance becomes automatic and invisible. When you flip a board over or come back after a break, take a second to check that the X is still where you meant it.

When it doesn't apply

For rough breakdown of oversized stock, where you'll clean up to final size later, exact placement barely matters and you can skip the mark. The habit pays off most on final, fitted cuts. Also, a knife line instead of a pencil removes the width ambiguity entirely for fine joinery.