Chopping away with an axe. The axe is an extremely valuable tool for woodworking.
With a rough mallet head, I started to 4 square the head. For the uninitiated, this means making sure all four sides of the block are square with one another. I mostly used a stanley #4 plane for this job.
Having marked the centers of top, bottom, and one face, I began boring a hole through from bottom to top.
Cleaning out the hole with a chisel leaves a nice through mortise. This picture also shows the rounding of the top of the head.
A rough result of fitting the oak handle.
The head all smoothed up and some scallops taken out with a spokeshave.
I took some scallops out of the handle too, mostly just by feel until it felt good in my hand.
After much smoothing with a scraper and sandpaper, I used boiled linseed oil over the course of a few days to finish it.