Angle of Blow (AOB) -- I measure the AOB from the "driving-nails-vector", which is a line through the platform and the support of the core. This AOB is different from the one used by most authors (Pelcin and Whitter), which is measure from the platform face. The significance of this difference is when I write, "increasing the AOB" it would be "decreasing the AOB" in the nomenclature of the other authors.

The driving-nails-vector is defined as the direction of the force that will not rotate the core. It will only compress the core. On large cores where the inertia of the mass becomes the support for the core, then the driving-nails-vector would pass through the platform and the center-of-mass.

I measure from the driving-nails-vector instead of the platform face because it makes the AOB independent of the platform angle. By separating the two, I can investigate the effects of one while holding the other constant. I have found that AOB is the dominant variable of the two with regard to their effects on flake morphology. However, since AOB is not preserved in the archaeological record, then platform angle is a good proxy for it since most off-margin strikes are perpendicular to the platform face.