overhauling a couple of old hatchets, one of mine and a friends.

remove old handles
heat to 780-800°C
quench 1.2-2" of blade depth in carbon rich oil
quench the entire head in water
test edge with file
bake at 200°C for two hours and allow to cool in open air
sharpen and polish edge
fit new handle and oil it.

they came up quite well, the edge is around the high 40's rockwell