Making flint blades can be done using direct percussion (as in the video), in-direct percussion using a punch and mallet or even using pressure! The different techniques produce different types of blades, but decent raw material is needed for uninhibited blade detachment. Faults or fossils are disrupt the shock travelling through the stone causing blades to terminate prematurely. Where people only has access to poorer material, their lithic products are often smaller. Laminar blade reduction (bl