Set out to make a Hardaway Dalton with some tough grainy rhyolite and got a center stack that was sent from satin himself. It was around 5 inches long and shaped nicely except for that nasty center stack. Flakes from both sides would go right up to end and stop. Eventually got a center snap trying to get that stack. Got out another spall and went to work. Happily it conformed to my wishes. Hope you like it!
