Tomahawks are simple but effective hand-to-hand combat weapons, still used by the elite U.S. Army Rangers, but for the average person they can also be used fruitfully for yard projects like trimming limbs or chopping kindling wood. Here is a guide to building your own throwing tomahawk, roughly based on the U.S. Army Rangers model.
Step 1: Find some scrap steel
Find some scrap steel between 3/16 and 1/4 inch (4.7mm to 6.35mm) thick, and at least 4 inches by 5 inches (10cm by 12.5cm) in size. You may find some in a junkyard or salvage yard, but it is also sold at industrial supply stores. Make sure it is not too heavy, but not too light that you cannot build up speed while swinging
Mark out a 3 1/2 inch (8.89cm) height by 5 inch (12.5cm) width, with a radius as shown in the image. The radius is hand drawn, as well as the blade curve, but an exact shape shouldn't be critical for the tomahawk to work.
Cut out the rough shape of the blade with a steel cutting blade on a circular saw to save time and effort when doing the finished cut later. You can make all cuts using a metal cutting bandsaw if you have one available, or even use a cutting torch.
Use a bandsaw or a jigsaw with an appropriate metal cutting blade to cut the curved edges of the tomahawk blade. Clamping the blade to a scrap piece of plywood that can be sawed through as you cut will make the task safer.
Use a grinder to smooth edges of the blade, and to sharpen the cutting edge of the tomahawk.
Clamp the blade to a welding table and position a 3/4 inch (1.9cm) pipe coupling along the straight, 2 inch (5cm) edge of the blade so that it is centered and aligned with the blade. Be careful here – if the blade ends up skewed, the tomahawk will not perform well.