Wooden dowels, or pegs, have a variety of woodworking uses. Sometimes, however, the smooth cylinders won't hold two pieces together. Cutting threads into the wooden dowel gives the peg a place for wood glue to hold. Most thread-cutting kits have a male and female component. This allows you to cut corresponding threads in a wooden hole to fit the threads on the dowel, giving you, in essence, the ability to create a wooden screw.
Cut a 6-inch section of dowel.
Place the end of the dowel in a vice so that the majority of the dowel is sticking straight up.
Place the thread cutter on the top of the dowel. Tap the cutter with a hammer. This makes the first cut and seats the cutter on the dowel.
Turn the cutter clockwise on the dowel. Depending on your model of thread cutter, it may have a handle, attach to a router, or you may just have to twist the cutter by hand.
Twist the cutter counterclockwise. It will crawl up the dowel. Before it reaches the top, turn the cutter clockwise and cut the threads a second time. This smooths the threads you have cut.
Cut threads into a hardwood dowel. Soft woods such as pine and birch are easier to cut, but the threads are more fragile and easily broken down.
Some models of thread cutters are designed for a specific diameter dowel. Be sure that the dowel fits the cutter.