Terminology:
In the following, references to skates, blades, or skate blades apply also to bobsled and iceboat runners unless otherwise noted. Sharpener or sharpeners will refer to small hand-held devices used to maintain or create sharp-edged ice-contact surfaces of skates in a hollow (concave) or flat shape by sliding the device back and forth along the blade. Abrader refers to the abrasive or cutting item (file, emery-cloth, stone, etc.) that grinds or cuts the blades. Convex and concave, which refer to the shape of the abrader or blade hollow, are defined as "radius" or "radii" in decimal-inch values.
Variables that determine the radius values needed:
1. In hockey, the forward requires great maneuverability for very sharp starts, turns, and stops; the goalkeeper requires great stability and side-to-side stepping/sliding action. Smaller radius for the former player, larger radius or flat for the latter. PA0 2. Speed skaters need a flat or large radius for maximum speed without sharp turns and with small variations for indoor smaller-turn rinks. PA0 3. Figure skaters may have several pairs of skates with a variety of radii for success in "compulsory figures" and the strenuous jumps and spins of the axels and lutzs. PA0 4. Added to the above are skaters' individual preferences as well as their choices depending on ice conditions (hard/soft, smooth/rough). PA0 A. Must have a self-aligning or simple-adjustment means to locate the center of the skate blade exactly in the center of the convex abrader. PA0 B. If the abrader is a long round file, stone, or cylinder, etc., that must be rotated after a sharpening to obtain a fresh, true convex radius, the worn surface must not affect the exact centering as stipulated in Specification A. PA0 C. Must be able to produce sharpened blade hollows of any radius value from 0.032" to the infinite value of flat. PA0 D. Abrader components or surfaces that become worn out in sharpening should be available at low cost from local hardware or sports stores to compete easily with high-cost, inconvenient commercial machine grinding. PA0 E. Guides for the skate blades must be easily and accurately adjusted to accommodate all skate blade widths and to allow for wear of the guides. PA0 F. Simple, small pocket tools, such as nail files, folding knives, and screwdrivers, should be the only equipment needed to adjust, maintain, and replace parts. PA0 G. The sharpener should be light in weight. PA0 H. Sharpeners should not have sharp, protruding parts to damage clothing or harm the user. PA0 I. Parts that may come loose or lost--like screws, nuts, or washers--should be standard hardware items. PA0 J. The number of accurate sharpenings possible before replacement of the abrader or blade guides should be high for convenience and cost efficiency.
Optimum Sharpener Specifications
Based on the above many variables, the following describe the optimum requirements for all skate sharpeners: