The old handle on this ball peen hammer was cracked, duct tape held for awhile but none of the local hardware (or big box) stores had one to fit. Whoever owned it before hadn't found a proper handle either and whittled a larger handle to fit.
The new handle is mystery wood salvaged from a broken TV tray leg, almost certainly a poor choice for a hammer handle but this hammer is rarely used.
The handle was shaped with rasps and files, the tenon cut on my table saw and rounded with files. The wedge was found in a pile of sawdust, a walnut scrap that happened to be the right shape.
I buffed the hammer head with a wire wheel for good measure. Everything got a coat of linseed oil, varnish causes blisters.
Special thanks to James Thompson for his article on making a hammer handle.
Making a Hammer Handle