I used a lathe, but this can also be done with an adz, hatchet, or chisel. The bottom of my masher is just under 3 inches in diameter and tapers into the handle which is an inch and 1/2 in diameter (this taper occurs over the course of 2 1/2 inches). The handle is a consistent diameter for 10 1/2 inches. The top end is 2 3/4 inches in diameter and occupies the final 1 1/4 of the pestle. Please alter the proportions to fit your hands. It helps to leave a little extra wood on each end until you are finished carving.