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
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
Pro tip: Steps 2 and 3 are the whole trick, and they're the ones people skip. Every ruined hinge gain starts with a chisel wandering past a line during the aggressive part of the work — the nicks and the 5mm border mean that by the time your chisel reaches the line, it's doing gentle paring, not chopping.