What is the hollow?
A – You probably know that your blade has two edges, inside and outside, and that there is a “hollow” between the edges. You may also know that the hollow can be “deep” or “shallow”, and be able to feel the difference by running your finger across the blade. Refer to the following figure showing a crossection of a blade. The blade is made of a piece of steel of some thickness (a typical freestyle blade is about 0.15″ thick). The bottom of the edge is ground out with a circular cross-section (see “how is a blade sharpened”, below). The radius of the circle is called the Radius of Hollow (ROH). The shorter the ROH, the “deeper” the hollow. A blade with a deep hollow will hold the ice better, but will also be grabbier and slower.
