Things You'll Need
Instructions
Cut the 2x4 wood with a coping saw or jigsaw, according to the pattern. Each of these will make an armrest for one crutch. Round the upper edges to make them fit comfortably under your arms. For a child, you can make them smaller.
Cut two poles about 50" long, shorter for a child or longer for a tall person. A strong wood like hickory, oak or ash is ideal. For a custom fit, have the person who'll be using the crutches stand naturally and measure from the ground to their armpit, and use that length. That should make the crutches an inch or two too long, so they can be cut to the best length when they're finished.
Drill a hole in the bottom center of the armrest, just big enough in diameter for the pole to fit tightly, and 2" inches deep. Tap the pole into the hole and glue it in place. If necessary, add a peg from the side to hold the pole in.
Have the person who'll be using the crutches try them out. If necessary, shorten them by cutting the bottoms off, and shape the tops to be as comfortable as possible.