The Great War – known later as the first world war – was a time of rapid innovation and discovery. Sadly, most of what we discovered and invented was faster, better, cheaper, and more horrifying ways of killing each other… but some of the discoveries also had uses after the war. Such as new ways to temper steel, which were later used in the EverReady Radio blades.

A quick online search don’t give any details on the tempering process used, but the kit pictured is identical to one I’ve inherited from a family friend.