Hollow sharpening (ROH)

Groove type- and depth on skate blade can be changed on sharpening. The most common groove type is radius sharpening, ROH (Radius of hollow). On this sharpening method, on the center of the blade has round "groove". When the ROH groove is perfectly centered to the blade, the both edges of the skate blade will be extremely sharp. These two sharp edges bites the ice, and makes tight turning possible.

Changing the depth of the groove (size of the radius), changes how the skate will perform on ice.

Small radius (r=10) creates extremely "sharp" blades. Skate bites on ice extremely hard, and the grip and agility is maximal. Small radius fits for offensive player who needs high agility. On the other hand, skating with small radius is exhausting and the skating efficiency is bad. Small radius gives high agility and acceleration, but has lack of glide and speed.

Big radius (r=30) gives good glide and excellent skating efficiency. Large radius does not give the agility and acceleration that you might get with the smaller radius. Big radius fits best for the defenceman who needs fast skating, even on backward skating. 

Good basic setting for skate radius is r20...r25mm. With this radius the skate performs well on most situations.

On hollow sharpening, the most important thing is to create the groove perfectly on center of the blade. Some skate sharpeners must be adjusted depending on the skate blade thickness. This means, that you always must measure the blade thickness, before sharpening. 

Always check the groove centering on blade, using the Parduc® T5 measuring gauge.