Grinding of skates and Blades.
All new skates and Blades must be ground/sharpened. The measurement is the radius of a circle in mm. The smaller the radius, the sharper the rail. The most common Hollow depth in Sweden is 19-22 mm. In the USA and Canada you usually have 13-16 mm. Keep in mind that a lower Hollow (sharper Blades) gives less glide. Try to test yourself and find your optimal Hollow depth.