Join Date: Sep 2008
Location: Bavaria, Germany - the center of 15th and 16th century gunmaking
It was only today that I noticed your query concerning the twisted haft of incendiary quarrel irons. I beg your pardon for not replying any earlier but as you may have gathered meanwile I was in hospital for the whole year of 2013 and can now only slowly make my way through all my posts.
As I have tried to show in this thread, all the iron heads with a very long and thin 'neck' and twisted haft seem to have been been shaped this specific way to safely hold the incendiary mass. We generally attribute them to the Late Middle Ages, ca. 14th to 16th century.
Nevertheless, many iron heads for incendiary crossbow bolts are known to show no twisting at all.