How to Make Joist Hangers

Measure the height of your joist. In most cases they will be 2-by-6s, which are 5 1/2 inches tall, or 2-by-8s, which are 7 1/2 inches tall. Measure the width; almost always this will be 1 1/2 inches, which is the standard thickness of 2-by lumber.

Double the height of the joist, add the thickness of the joist, and cut a piece of 1 1/2 aluminum angle that length, using a hacksaw. Clamp the angle on the edge of a table with C-clamps to make a clean cut. Drag the saw across the material to create a slight groove, then cut through it with a push/drag motion, cutting with each stroke until it is cut through.

Measure in from each end of the angle piece you cut, the height of your joist, and mark the angle. Clamp the piece to your work table, with one face flat and one extending up from the work table. Cut the angle through the edge that is extending up on both marks, to create a 1 1/2-inch flap.

Grasp the flap with locking pliers and bend it down, so that it folds along the crease at the corner of the angle. Bend it back up, then down again repeatedly until the flap weakens and breaks through.

Position a piece of joist material on edge and set the cut and notched angle on top of it, so that the notch is centered on the edge of the board. Bend the sides of the angle down, to create a flat bottom, 1 1/2 inches wide. Use a hammer to bend it crisply, so that the bottom has fairly square corners that fold against the joist tightly.

Fit the hanger against the rim joist, or other frame where the joist will be hung, so that the face of the flange goes flat against it. Drive screws through the holes in the perforated angle to mount the hanger. Fit the joist into the hanger and drive screws through the holes against its face to hold it in place.