Lay Out the Mortise
Locate the back of the hinge on the door.
Use the combination square as a gauge with 1/4 inch of the blade exposed.
Draw the back edge of the hinge with a pencil.
Position the hinge blade on the edge of the door where it will eventually be attached.
Score along the ends of the hinge leaf with a sharp knife, using the unattached hinge leaf as a guide.
Use awl to score along the back edge of the hinge. An awl is the better tool to use for scoring in this step, as it is less likely to skip and "follow" the wood grain than a knife.
Hold the long edge of the hinge leaf against the edge of the door to measure the depth of the mortise needed. Score along the edges of the hinge leaf with the awl to mark the depth.
Chisel the Mortise
Hold the chisel at a 45-degree angle and cut across the grain, inside the marked-off mortise area on the vertical edge of the door. Use quick, controlled cuts in 1/4-inch increments, gently tapping the chisel with the heel of your other hand until the blade point reaches the depth line previously scored.
Place the chisel blade in the awl scoring, bevel side up, 1/2 inch from one end of the mortise.
Slice away the waste wood with the chisel blade to create the mortise depression. You may need to softly tap the handle of the chisel with a hammer to begin the paring, but you should only use gentle, manual pressure from then on.
Use cardboard shims made from the box the hinges came in, if the mortise is slightly too deep for the hinge leaf. One or two pieces of cardboard cut to size can be used to make up any slight error.
Things You Will Need
- Combination square
- Hinge leaf
- Sharp knife
- Sharpened chisel
- Box from hinge or other thin cardboard
- The sharper the chisel, the easier the task will be to perform, and a cleaner mortise will result.