I am a bit late to this party, But I will throw in my 2 cents nonetheless. I have a maul I use all the time that I made myself and it was quite simple to make it is just a variation on what some others have mentioned. I used 1/2" all thread but 3/4" would be beefier and UMHW plastic rod for the head. a foot of 2.5" UMHW is enough to make 2-3 mauls depending on how heavy you want them and cost me $18 I cut the rod to length in my case about 3.5" long and marked centre and drilled one end with a 1" forstner bit to countersink the nut and a 1/2" hole all the way through with my drill press. the handle I made of leather washers and a golf ball flattened on 2 sides and countersunk like the maul head as a neater termination than just having a nut and washer on the end of the handle. Tighten everything good and snug and clean it up as you see fit and you are off to the races with a very functional maul for about $8 per maul.
