Transfer a Miter Point to the Other Face With a Razor Blade

The Problem

Mitering a box beam, the long point of the cut is laid out on one face — but the track saw cuts from the outside, where that mark doesn't exist. Wrapping a pencil line around the beam adds a chance to drift at every edge.

The Technique

1. With the long point marked, line your square up on the layout line.
2. Stick a razor blade into the wood at the point, registered against the square, and let go of it.
3. The blade now stands proud at the exact point — a physical index you can feel and butt against from the other face. Bring the square or the saw track over and register it on the blade.

The blade does what a pencil mark can't: it exists in space, not on a face, so the reference survives the trip around the corner. The reel shows the whole sequence in a few seconds.