|Presented by:||Ron Chisholm - a dedicated hockey fan, parent of four players, past player and coach of many years, and expert skate sharpener since 1983.|
Radius of Hollow or Hollow Grind
When skates are sharpened, they are hollow ground creating a concave surface with two distinct edges. The edges give the skater the ability to control the skates for turning, stopping, and starting. This hollow grind makes it easier for the edges to bite into the ice. The ROH is determined by the shape of the grinding wheel. Before sharpening the skates, the grinding wheel is dressed with a diamond tipped tool to the desired radius. When the skate is sharpened, the blade is ground to match the shape of the wheel, creating the hollow grind with two distinct edges. See this short video on standard ROH wheel dressing. You might also want to consider using a flat bottom dressing instead of the standard ROH. The flat bottom dressing is intended to increase the glide (and speed) of the skater without sacrificing cutting ability. Skating requires less effort to obtain the same (or better) results thus resulting in less muscle fatigue. With a standard Radius of Hollow, you must compromise between speed and cutting. A shallow hollow gives better speed, but the deep hollow enhances maneuverability. The choices with flat bottom relate primarily to cutting and edge control. For more information see the page on Flat Bottom Form Dressing.
The question to be asked now is how deep should this hollow in the skate blade be? The Radius of Hollow (ROH) is measured in fractions of an inch, typically from 3/8" (very deep) to 1-1/2" (very shallow). Determining what is right for the individual can be a bit tricky and may require a little experimenting. Different people will have different ideas about what the ROH should be. In actuality, there are many factors which must be considered. Ice conditions, player size, and type of player (fast skater or stickhandler) influence what is best for the individual. The ROH used is the result of a compromise for speed and maneuverability. Personally, I recommend using the shallowest hollow that the player is comfortable with. Some examples of ROH used by current and former NHL players are:
The above preferences vary greatly, but in general, about half the players use an ROH of 5/8". The other half are split relatively even between deeper and shallower hollows. Coffey was probably on the extreme end of the shallow grind, but used this to benefit his long smooth stride. It should be noted that, in the past, goaltenders normally used a shallow grind of 1" to 1-1/2". This was due to the requirement to move side to side without fear of catching an edge, causing a fall. Additionally, the goalie skate usually had a much wider blade, which resulted in more pronounced edges for a deeper grind. The newer goalie skates are being made with blades that have a thickness similar to that of a regular player's blade. Many goaltenders are now using deeper hollows in order to get more edge bite to suit the butterfly style of goaltending. Typically, they are using 3/8" to 5/8". Goalie skates are also being made without the extra cowling around the skate, which reduces the weight of the skate. Construction of the leg pads gives the additional protection required for the feet.
After a skate has been sharpened, the edges will be sharp regardless of the depth of the hollow. Speed skaters use a flat hollow to allow for more speed, but they sacrifice on turning ability. Obviously, this type of sharpening would not be good for a hockey player. So, the question that must be asked is not whether the skates are sharp enough, but is the hollow deep enough? If, after sharpening, the player says that the skates are not sharp enough, what he/she is really saying is that there is not enough edge to suit his/her style of play, and a deeper hollow is wanted. The ice hardness must also be considered. On soft ice, the skates will tend to sink in deeper and a shallower hollow may be desired. Conversely, when the ice is hard the skate may have a tendency to slip. In this case, a deeper ROH may be necessary to overcome the problem.
Generally speaking, a shallow hollow will tend to increase the skater's speed as there is less friction between the blade and the ice and a better glide is produced. This also results in less energy being used to skate. Using less energy means that there will be less leg fatigue. On the other hand, a deep hollow will allow for quicker, tighter turns and better stopping due to more bite on the edge of the skate. This is where the compromise has to be determined.
If the player's skates seem to drag and he/she is not getting the usual speed, the hollow may be too deep. Conversely, if the player feels that maneuverability is not as good as normal, the hollow may be too shallow. Lighter players can tolerate a deeper ROH as they do not have much weight bearing down on the ice, while heavier players may find they are working very hard and not getting the desired speed. Another thing to keep in mind is that a deep hollow will produce more fragile edges, which are subject to damage, so, additional care must be given to these skates. They will also require more frequent sharpening to hold the edge.
After reading this information, you might be wondering what the skate shops give you for a hollow when you just walk in for a skate sharpening. As you might expect, this will be different from place to place. Some will say 1/2 inch; others say 5/8 inch, while others might not even be able to tell you what the machine is set for. In some cases, you will not be allowed to get anything but what the shop has set as its standard. No matter what you are told, if the grinding wheel is not properly dressed before EVERY sharpening, the hollow grind will not be accurate. Each time the wheel is used, it is worn down causing less of a hollow. I bring this up as I know that many, if not most, places will sharpen multiple pairs of skates before dressing the wheel. So, if you are not fortunate enough to be the first sharpening after the wheel has been dressed, you may not be getting what you think. Personally, I tend to go with a shallower grind of 11/16 inch as my standard hollow. This is a true setting as I will dress the wheel for every pair of skates and sometimes for each skate if necessary. I recommend that the skater go with as shallow a hollow as possible without sacrificing maneuverability. On the other hand, I will give the skater any hollow grind setting that is requested. Do not hesitate to ask for your preferred ROH.
Additional Sharpening and Skate Information
on this site has been collected from official scoresheets and from on ice
observations. As such, the final statistics are not to be construed as
official or sanctioned by the Salem High School Athletic Department or by the
NHIAA. However, much of this information is not available from any other
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