Platform Angle -- is the angle formed by the intersection of the platform face and the dorsal face of the core. See image "A". It is an easy variable to measure on a core and most research studies obtain this datum.

Platform angles are not as easy to measure on flakes. The flake in image "B" has an exaggerated reduced margin on the right edge of the image. Does one measure the angle between the platform face and the bevel that created the reduced margin or should one measured it from the true dorsal face? Image "C" is a flake created by a margin strike and the crack initiated at the point of impact, which removed all the platform face. Where does one measure the platform angle on this flake?

Most platform angles in the archaeological record range between 50 and 60 degrees regardless of time or space. For example, this range can be seen on Levallois cores (Van Peer 1992:24) or Folsom, channel flake preforms. When a platform is constructed (edge is turned) to remove flakes from a particular face of the core, it is done in a manner that minimizes the loss of the width or length dimension. The natural outcome of this minimizing effort is a platform angle between 50 and 60 degrees. Further support for this concept is the resharpening bevel on knives and points. These were hafted tools and the owner wanted to maximize their use life. So, they were beveled in a manner that minimizes the lost of material. The bevel on these tools is always between 50 and 60 degrees.

Many researchers have noticed relationships between platform angle and flake geometry. These same researchers also measure angle of blow (AOB) from the platform face, which couples the two variables (platform angle and AOB) and makes them dependent on each other. If angle of blow is measured independently of the platform face, the variation in flake geometry is a result of the angle of blow and not the platform angle. 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.