What's inside
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Tools and setup
A clean hinge mortise depends more on accurate marking and controlled cuts than on owning a specialized jig. You’ll need a sharp chisel, a marking knife or sharp pencil, a combination square, a hammer, and a way to hold the door steady. A 25 mm (1 in.) chisel suits many standard residential hinges; a 19 mm (3/4 in.) chisel is easier to control on narrower leaves. Match the chisel to the hinge width rather than forcing a too-wide blade into a corner.
A basic wood chisel set is adequate for occasional hinge work, provided the blade is sharp and its bevel is in good condition. A dedicated bench chisel is nicer to handle, but you don’t need an expensive one for a few doors. Avoid using a screwdriver or a dull general-purpose chisel: they tend to crush the fibers at the edges, and a screwdriver’s shape makes depth control poor.
Work with the door lying flat on padded supports, or clamp it upright if that gives you a secure, comfortable working position. Keep the hinge side accessible and support the door so it cannot rock. A sharp marking knife leaves a more precise boundary than pencil, especially in paint-grade softwood. If you use a pencil, make the line thin; a heavy line can hide a small but visible error.
Mark the hinge position
Place the hinge at the intended position and mark its outline. On a typical interior door, the top hinge is often about 175–200 mm (7–8 in.) from the top, and the bottom hinge about 250 mm (10 in.) from the bottom. Follow the existing positions if you’re replacing hinges or matching a frame. Wider or heavier doors may need a third hinge.
Use a square to carry the hinge’s edge marks across the door edge. Score the outline with a knife, holding the blade against the hinge leaf; make several light passes rather than trying to cut deeply in one stroke. Keep the hinge flat and still while marking. A hinge that shifts even slightly can leave an oversized mortise.
Measure the hinge thickness with a rule or caliper if you have one. That thickness is the target mortise depth: commonly around 2–3 mm (roughly 3/32–1/8 in.), but the hinge is the reference, not a standard number. Lay the chisel across the hinge leaf to check its thickness if needed. A mortise that is too deep pulls the hinge below the surface; one that is too shallow leaves the leaf proud and can make the door bind.
Cut the mortise in controlled passes
First, make a shallow cut around the scored outline. Hold the chisel bevel toward the waste and the flat back toward the line. Tap gently with a hammer, keeping the blade vertical. The scored fibers help stop the cut at the boundary. Don’t lever the chisel against the finished edge; that can tear out wood beyond the line.
Next, make a series of light cuts across the waste, spaced about 3–5 mm apart. Angle the bevel slightly toward the center of the mortise and tap just enough to establish short grooves. Then hold the chisel nearly flat, bevel up, and pare away the ridges between them. Take thin shavings. Repeated heavy blows are faster only until the blade dives too deep or splits the corner.
Check depth frequently by placing the hinge leaf in the recess. Stop when the leaf sits flush with the surrounding surface, or just a fraction below it. Keep the bottom level and the outline crisp. If you’re close to the target depth, switch to hand pressure and short paring cuts. A sharp blade removes material predictably; a dull one needs more force and is more likely to skate.
To square a rounded corner, place the chisel on the marked line and pare inward in small cuts. Many hinges have rounded corners, so you can also leave the mortise rounded to match. Don’t force a square corner if the hinge is rounded: a small gap is usually less noticeable than a chipped edge.
Chisel or router: which makes sense?
| Method | Best for | Trade-off |
|---|---|---|
| Chisel by hand | One or a few hinges, repairs, and work without power tools | Low cost and good control, but slower; results depend on sharpness and careful marking |
| Router with hinge jig | Several doors or repeatable work on matching hinges | Faster and consistent, but the jig and router cost more and still require a sharp chisel to clean corners |
| Pre-cut or adjustable hinge template | Occasional repeat jobs where setup time matters | Can improve repeatability, but may not suit every hinge size or door edge |
For a single door, a chisel is usually the sensible choice. If you’re mortising several doors, a hinge mortising template can save time, though it does not eliminate careful positioning or corner cleanup. A cheap template is fine for occasional use if it holds firmly and matches the hinge size; a loose jig can produce a mortise that is consistently wrong.
Check the fit and avoid common mistakes
Set the hinge in the mortise and check all four edges. It should sit flat without rocking, and its knuckle should line up with the door edge as intended. If one area is high, pare only that spot. If the whole leaf sits proud, remove a thin layer from the bottom. Don’t deepen the entire recess to fix a small high spot.
If the mortise is slightly oversized, don’t keep cutting to make the edges look uniform. A small gap under the hinge leaf is usually hidden once the hinge is installed. For a visibly chipped edge, glue in a thin sliver of matching wood, let it dry, and pare it flush before marking again. On a painted door, filler may work for a minor cosmetic nick, but it is a poor substitute for wood where a screw needs to hold.
Before driving screws, drill pilot holes centered in the hinge’s countersunk holes. Use a bit sized to the screw’s core, not its full outside diameter; for common hinge screws, a pilot around 2 mm (5/64 in.) is a reasonable starting point in softwood, but check the screw and timber. Driving screws without pilots can split a narrow door edge or pull the hinge out of position. If the chisel starts to feel dull, stop and sharpen it: extra force makes slips more likely and the mortise less clean.