Woodworking jigs are designed to help you repeat the same angle of cut (45-degree, 90-degree or even circular) with minimal effort so that each piece is cut the same. For projects such as building deck railing, a woodworking jig is an invaluable tool. You can also make woodworking jigs to guide you through any number of complicated cuts. Learn how to create a simple angle jig so you can learn the basics and be able to make any kind of woodworking jig you need.
Measure and cut a rectangle of 3/4-inch plywood 2 feet wide by 2 1/2-feet long. Using your speed square, mark a 45-degree angle at the top of the piece so the angle goes across the narrower edge of the board. Cut the angle with your circular saw. You should now have a rectangle with a straight bottom and an angled top.
Measure, cut and nail two pieces of 2-by-4 board along the lengthwise edges of your plywood. Turn the plywood so it is resting on the rails you just created as if you have just made a low table. Put several 2-by-4s on your worktable so the long edges are butted together and the ends are even. Place your plywood jig over the 2-by-4s. You will want the 2-by-4s to fit snugly between the two rails. Using the C-clamps, clamp the plywood jig down over the loose 2-by-4s and onto the table, tightly enough so they do not move.
Using a hammer, tap the ends of the 2-by-4s so that they are even again. Cut the angle into the boards by using the angle of the plywood to guide the blade of your circular saw.
Unclamp your woodworking jig and remove it. Line up the high points of the 45-degree cuts on the 2-by-4s so they are even. Measure down on the two outside 2-by-4s the length you need the pieces to be. Put your woodworking jig back over the 2-by-4s so the straight edge of the jig is lined up on the two marks. The jig should cover the angled ends of the board and the straight ends should stick out. Clamp the jig back down and cut through the 2-by-4s in a straight line, using the bottom of the jig as a guide. You have, with 2 cuts, made the exact same angled pieces out of a series of 2-by-4s.
Add some rails to the top of your jig and a 2-by-4 between them set to the overall length (from the straight edge) that you need your pieces. This way you can flip the jig, butt the high ends of the angle to the crosspiece and cut the overall length without the steps of measuring and carefully moving each piece.
Always test to make sure that your woodworking jig is firmly clamped down, if it is loose, it could not only throw off your cut, but it could spin free and cause injury.