How to Mortise Hinges in a Metal Door

Measure for each hinge placement on the door with a tape measure. Measure from the inside top of the door frame to the top of the each hinge on the frame. Transfer those measurements to the door, placing a mark for the top of each hinge. Lift the metal door blank into the opening, and ensure that the marks on the hinge side of the door match the tops of each hinge leaf on the frame.

Lay the door on its edge with the hinge edge facing you. If necessary, ask a friend to hold the door while you measure and mortise the hinge area.

Adjust a combination square to have ¼ inch of the blade exposed. Position the hinge leaf onto the edge of the door, lining up the top edge of the leaf with one of the marks. The sleeves of the hinge should point to the inside of the door. Place the combination square on the outside edge of the door next to the hinge leaf. Once the leaf is square, trace the outline of the hinge. Repeat for the other two hinge locations.

Place the flat edge of the hinge on the inside of the door, holding the edge against the door under the tracing. Trace the thickness of the edge onto the inside of the door panel.

Insert a cutting wheel into a rotary tool. Cut the tracing out of the steel door skin with the rotary tool. Do not cut into the wood frame with the rotary tool. Remove the steel mortise cut out.

Chisel the wood frame only to the hinge thickness with a wood chisel and hammer. Repeat for all three hinge locations.