A few weeks back, we published Three Simple Experiments All Hockey Players Ought To Consider. In that post we talk about the three main variables a skater can adjust to try and find the rocker, pitch and hollow that best suits their skating and playing style.
Today, we want to zoom in a bit on just one of those variables; the hollow. There are 2 variables you can adjust when selecting a hollow; the shape and the depth.
It is important to know that the hollow of your blade can be sharpened to different shapes.
ROH - The most common cut, ROH (Radius of Hollow), is essentially an arc of a circle. Grip and glide are determined by the radius of that circle and typically range from a 3/8" radius to 1 1/2" radius, with 3/8" providing the greatest amount of "bite"
FIRE™ (Sparx)/Flat Bottom BFD™ (Blademaster)- As you can see in the graphic, this shape provides the radius edges familiar to those accustomed to ROH and also includes a flat bottom which limits the edges from sinking into the ice as deeply as they would on a traditional ROH. This combination increases glide while still maintaining enough "bite" to make sharp turns and stop short.
FBV™ - Blackstone's Flat-Bottom-V - Similar to the Flat Bottom BFD/FIRE, but there is one noteworthy difference. The Flat-bottom-V has all straight edges as opposed to the radius edges of the FIRE Ring.
While not limited to these 3, these are the most common shapes used by hockey players. It is also worth noting that while you will find players of all levels that prefer one shape over the others, there is no scientific evidence proving that one is better than the other. That said, we don't need science to know what feels best to us and this is why we encourage players to experiment.
ROH - As mentioned above, the radius of hollow is based on a circle. The smaller that circle (e.g. 3/8" radius), the deeper the hollow will be, hence providing the skater with greater grip or bite. The larger the circle (e.g. 1 1/2" radius) the shallower the hollow will be, hence providing great glide. Typically you can increase in size by 1/16 of an inch from 3/8" to 1 1/2" (3/8", 7/16", 1/2", 9/16", 5/8", 11/16", 3/4", 13/16", 7/8", 15/16", 1", etc.). As you can see, this provides just a ton of opportunity to try different options and find one where you feel you can skate at your fastest and still feel confident that you can stop short, start quickly and make sharp turns.
Generally speaking, flat bottom options are offered in a much smaller range. There are likely 2 primary reasons for this; 1) most people prefer (or are satisfied with) one of just a few options and 2) the overhead for a shop owner to offer a wide range of flat bottom options is more prohibitive.
FIRE™ - The Sparx FIRE Rings are offered in 3/8, 1/2, 5/8 & 3/4 - these numbers represent the ROH associated with the radiused inside edges of the FIRE Ring. As such the grip-to-glide relationships are relatively the same as ROH with the 3/8 FIRE providing the greatest amount of grip and the 3/4 FIRE providing the greatest amount of glide.
Flat Bottom BFD™ is offered 3 options; X6 (similar bite to 3/8" ROH), X7 (similar bite to 1/2" ROH) and X8 (similar bite to 3/4" ROH). Not surprisingly, the most common of the 3 options is the middle-of-the-road X7.
FBV™ - While it is possible to try many different FBV options, typically you'll find that shops offering FBV sharpening offer four options 90/50, 90/75, 100/50, 100/75. These numbers represent -thousandths of an inch (width of the flat part of the blade) / ten-millionths of an inch (the height of the fang) -, so we are dealing with very small numbers. To provide some context, here is how these popular FBV sizes relate to traditional ROH.
90/50 = 3/4" ROH (more glide)
90/75 = 5/8" ROH
100/50 = 1/2" ROH
100/75 = 3/8" ROH (more grip)
Knowing Is Not Understanding
That we are a bit nerdy when it comes to skate sharpening is no secret. It seems that every day we are learning and every day we have something new we want to test.
Which brings us to our main point. Knowing the differences between ROH and FIRE and FBV from an academic point of view is great, as is having an understanding of how the depth of the hollow affects grip and glide. This knowledge gives you a place to start from as you consider your own options; it allows you to make educated guesses. But to truly understand what those differences can mean to your game, you've got to get out on the ice and do some real testing.
This week, we did just that. Thanks to Bauer's Lightspeed Edge, we were able to easily conduct blind tests. The goal was twofold; we wanted to - without bias - figure out what sharpening style felt best to us. We also wanted to see if we could identify each individual hollow based purely on the knowledge we have about hollow shape and how it affects grip/glide and our assumption of what it should feel like on the ice.
We each sharpened 3 pairs of steel. We included 1/2" ROH, 1/2 FIRE and 3/4" ROH and headed over to the rink. We each selected and inserted steel for the other skater in order to preserve the anonymity of the hollow. It was fascinating. To be clear, there were significant differences in how each set of steel felt, but not always in the ways we expected. It became instantly clear that anyone who is serious about hockey and is looking for ways to constantly get better ought to conduct a similar evaluation.
If you carry extra steel, just do it. If you are skating on a 1/2" today, get one set sharpened at 3/4" and try it out next time you are on the ice. You just might find a way to gain a little extra speed. If you do not carry extra steel or if you skate on something other than Bauer, make the effort to ask for a different sharpening next time you are at the shop. Sure, there is a little risk in it, but trying something new for a mid-week practice will minimize that risk and could have a huge benefit.
We will definitely be conducting more tests in the future and will continue to share our results and insights.
Have you tried this or a similar of test before? What did you learn?