A year or two or three ago, I pruned one of my Australian brush cherry trees, and had a few forearm-sized logs lying around. Recently I saw an episode of The Woodwrights Shop where Roy makes a mallet. It's a perfect match: the short piece of a random log becomes the head, and a slightly less short piece of cork oak (from a tree I planted in about 1987) becomes the handle.
Usually one wants longer, straight logs, but for a mallet, short pieces are good enough, so it doesn't matter if the logs aren't very straight.
The brush cherry is clearly a dense wood - one notices immediately that even a seasoned piece is rather heavy. Upon working it, it becomes clear that it's also quite hard. Mortising the hole took a lot of effort, especially lacking a mallet to drive the 1 inch chisel. (I simply used another random length of long I had lying around - again wood from the same tree that's the source of the mallet's head.)
I've left the handle slightly oversized, since it might not have finished doing all the shrinking it's ever going to do. Maybe in a year or 10 I'll bring it down to final size so that so much of it doesn't stand proud of the head:
The taper is quite visible on the handle, and when I make another mallet (a bigger one - this is just a baby) I might use a more acute angle. On the other hand, the rather strong taper makes it easy to knock down the mallet if I want to, yet is gentle enough that the mallet doesn't spontaneously disassemble in use:
This little mallet seems perfectly capable of doing its job. It's light enough to not be tiring to use, and the lightness permits better control than a more anvil-like model would. But I can foresee a need for a heavier, anvil-like mallet. Something to drive a 1 inch chisel to mortise some extra-hard wood. That would've come in handy while making this junior mallet.