There is a great deal of science and technology associated with skating, including skate design and skate sharpening; the field is known as �skateology.� While you don�t need to be a skateologist to get the most out of your skates, it helps to understand some of the terminology, to know how sharpening can affect the performance of your skates, and what questions you should ask.

There are some skate sharpening definitions that you�ll want in your hockey vocabulary. These include the parts of the blade, like the �rocker� and the �hollow,� and terms for blades that are flawed like �out of square� or �high edge.� Since the material used to make your blade influences how long it will keep an edge, you�ll want to know about blade material. You�ll want to know how often to get your skates sharpened, and some hints for problems that may result from incorrectly sharpened blades.

The Rocker

No, not Tommy Lee or Eddie Van Halen. The �rocker� refers to the curved profile of the blade running along its length. Whereas skates of former generations used to be flat, forwards and defensemen of today skate on curved blades, which are said to have a �rocker� (netminder�s blades are flat, and have no rocker). Along the curve of the blade, or rocker�which runs front-to-back�there is a balance point which affects the center of gravity for the skater.

When skates are first purchased, this balance point (or pivot point) is in the center of the rocker. Many skaters will be satisfied with the rocker left alone with the balance point in the center. However, if you are a defensemen, you may want that balance point moved forward along the curve of your blade in order to set your center of gravity back, providing an advantage for backward skating. Meanwhile, the forward may want the balance point moved to the rear of center in order to shift his center of gravity forward, providing an advantage for forward skating.

The skater who thinks that his skates make him feel like he is falling forward or falling backward may have the balance point in the wrong location. His problem might be solved by requesting that his skate sharpener move the balance point of the rocker either forward or back along the curve to correct the center of balance.

The �hollow,� also known as the radius of hollow, refers to the depth of the groove ground into the running surface of a blade during sharpening. If you turn over your skates and look at the groove between the two edges of the skate blade, you�ll see the hollow. The depth of that hollow can influence your skating, and different skaters will select different hollows for their skates. Decisions regarding the hollow will often depend on what position one plays and also on the hardness or softness of the ice surface.

When the hollow is shallow, making the bottom of your blade relatively flat, you are more likely to hydroplane along the ice. Forwards and most recreational skaters who want to get speed out of their skates will demand a relatively shallow hollow. However, when the hollow is deeper, the blade will cut deeper into the ice, providing for more control.

Defensemen, who need to be able to turn quickly and make quick starts and stops, will prefer a deeper hollow. Goaltenders choose much flatter hollows than the skaters in front of them, especially the �sliders� and �butterfly� style goaltenders who tend to stay in the crease. But the skating goaltenders who come out of their crease often use a deeper hollow than their stay-at-home counterparts, for better turning and more bite into the ice.

The hardness of the ice surface you usually skate on may also influence your choice in depth of hollow. If the ice is soft (for instance, it�s slushy and has lots of ruts in it), you may want a shallower hollow to help you hydroplane over the ice. When you skate on harder ice (which doesn�t get very chewed up, even during public sessions) you may choose a deeper hollow to permit more of a bite into that hard ice.

The unit of measurement for the depth of the hollow is based upon the radius of a circle on which the hollow would accurately fit. In illustration No. 1, three different skate blades are shown positioned on top of circles, each with a different radius. The top blade was cut for a goaltender, using a 1� radius, so it has a very shallow hollow and is relatively flat. For the middle blade, the skate sharpener made the radius of hollow 1/2�, which is the hollow of choice for most forwards and recreational skaters. In the bottom example, the defenseman�s blade can fit accurately upon a circle with a 7/16� radius, which means its hollow is deeper.

Players from the Southwest who are taking a trip to play in Canada should keep in mind that the Canadian ice tends to be much harder than Sunbelt ice. Some northbound skaters use a 3/8� radius for a much deeper hollow during the trip. However, upon returning home they go back to the shallower hollow.

Your local skate sharpening expert will likely have a radius of hollow gauge which he can use to set the grinding equipment to your desired hollow. This gauge has numerous cutouts of portions of circles of various radius lengths. At some skate shops, the sharpeners may use other lingo to identify different depths of the hollow. It�s best to spend a few minutes with your sharpening expert to let him know your preferences for the rocker and hollow, and to understand how he identifies the various settings.

A skate that is out of square, or has a high edge, has one edge that is higher than the other. This can lead to a skate turning much more easily in one direction than the other. This is analogous to driving a car that needs a front-end alignment.

The way to determine if your skate has its two edges square to the side of the blade is to turn the skate upside down, hold it up to where you can look across the length of the blade, and place a quarter over the two edges. If the side of the quarter and the side of your blade comprise a �T�, then your skates are correctly in square. But if one side of the quarter sits higher than the other, you have a high edge, and your skates are out of square. See illustration No. 2.

Modern hockey skate blades are made from either �high-speed steel,� �stainless steel,� or they may be �titanium-coated� (these are the gold colored blades). High-speed steel is less expensive than stainless steel, but unlike stainless, high-speed steel can rust. If you find rust spots on your stainless steel blades, its because you�ve come in contact with someone wearing high speed steel.

Titanium coats may be put over either high-speed steel or stainless steel when the blade is made. A titanium-coated blade does not rust, keeps its edge longer, and does not get dinged as deep when coming in contact with other objects. Titanium-coated blades, naturally, are more expensive than the other types.

If you use the hard plastic walking guards, use them only for protecting and transporting your skates, but not for storage. Since the plastic walking guards get damp, they can rust your blades if left on the skates for long periods. For storage, the best thing to do is take the walking guards off, wipe your blades dry and put them in cloth blade guards.

A rule of thumb for beginners and recreational skaters is to sharpen the skates every 10-to-15 hours on the ice. For example, after skating at fa handful two-hour public sessions, it�s time to get your skates sharpened. This is especially important for beginners because they need consistency in their edges while climbing the learning curve of skating ability. Some hockey players may choose to get their skates sharpened before every game, even though it can be rather expensive.

Out of square (above); correct (below).

Do your skates need to be sharpened? Here�s how to tell: Hold the skate upside down with the toe in one hand and the heel in the other. Holding the skate up to the bright lights inside the rink, pivot the skate toward you the same way you would turn a thermometer toward you when you�re trying to read it. If there are dull spots on the skate, they will show up as little spots and lines of reflected light, and it�s time to sharpen.

The �tilt-and-look� method is superior to, and safer than, the old method of running the back of your fingernail across the blade to see if you leave shavings on the blade. Injuries are reported about once a month by people who use this rather inaccurate method. Neverthe-less, some people use the fingernail method to test consistency of the sharpness of each edge of the skate.

Yes. Beginners can run into deep trouble if their skates are too sharp. For most skaters who have skated less than two or three years, some amount of �tuning down� (dulling of the blades) will be required. If the blades are too sharp for the skater, he may find himself stopping too fast�the skates stop, but the body keeps going.

Some skaters will take their freshly-sharpened skates and run them along a piece of wood to tune them down. This is a less accurate method than having your skate sharpening professional use a consistent method of tuning down your skates to your ability and your desire. Goaltenders usually request that their skates be tuned down more than skaters.

Was the sharpening done correctly?

Here�s how to tell: First, take a look at the bottom of the blade and observe the �grain of the sharpening� along the length of the hollow. Do the lines run straight along the length of the blade, or are they crooked and run crossways between the edges? Straight lines indicate that the skate was ground correctly. Crooked lines will lead to friction and slow you down. Another test is to carefully run a pen along the length of the hollow and check to see if the line you have drawn runs straight and smooth.

Incorrect handling during a sharpening may lead to a skate blade getting �burned.� If the blade is discolored after sharpening, the skate may have been overheated from being held to the grinder either too tightly or for too long. This means the �temper� (or hardness of the metal) may be lost, which leads to edges wearing off faster.

Diagnostics

If you find that at certain speeds your skates wobble back and forth and become difficult to control, this probably isn�t due to your skating ability. It�s probably due to one or both of your skates being out of square (having a high edge). Try the method described above for determining if your skates are out of square, then take your skates along with a description of the problem to your skate sharpening professional.

A skater who finds his skates slip too much may need a deeper hollow. As mentioned above, the deeper hollow will permit the skate to bite into the ice better.

If your skates seem �sluggish� after a sharpening, and you�re used to getting more speed, you may be used to a shallower hollow. Going to a shallower hollow will provide you more speed, but�in the trade-off�you may give up some of your cornering abilities. l