Broke head of my soft face hammer. I thought it was half decent, because it was mid price model.
First I thought of ordering replacement head, but probably it would have been even worse and it is always a 3 weeks of wait.
First I measured the parts and they were funny dimenssions, not really metric or imperial. More like drawn to something, made close to nominal and then shrunk to something else.

Even the hread was something, that I took for 3/8" UNF, but when I took ti to fastener shop the owner said that it was probably just very undersize metric M10. Bought few M10 set screws. I turned and threaded piece of 30 mm POM and it has been taking some pounding allready, without breaking.
Took 9 mins. vs. 3 week wait and and about 2€ worth of hole in the ozone layer.
Pekka