Cut a Hinge Mortise by Hand: Knife Lines, Relief Nicks, Then Chop

The Problem

A router with a hinge template makes quick work of hinge mortises — but there's one door to hang, the router's at the shop, or the mortise lands where a template won't sit. Cutting one by hand is a genuine carpenter's skill, and the difference between a crisp hinge gain and a chewed-up one is a few small moves at the start, before any real chopping happens.

The Technique

1. Mark with a knife, not a pencil. Hold the hinge in place and knife the line on either side and down the edge. A knife line is both more accurate than pencil and a physical groove the chisel can register in.
2. Nick the ends. Take a little nick out of each end line first — so when you start chopping in earnest, the chisel drops into the nick and can't move or skate past your line.
3. Stay off the edge. Along the face edge of the mortise, work about 5mm inside the line for the same reason: the untouched border stops the chisel drifting back past the line while you do the heavy removal.
4. Depth cuts. Chop a series of closely spaced cuts across the mortise — up and down, up and down — to the hinge-leaf depth. The waste between the cuts breaks out easily.
5. Pare clean. Come back to your knife lines and pare the mortise floor and edges to final size. The knife lines give you a crisp shoulder to finish into.
6. Drill for screws with a self-centering bit. It registers in the hinge's countersunk holes, so the screws pull the leaf in straight and the heads finish dead flat — a cocked screw head is enough to hold a hinge leaf proud.