Flat bottom V hollow sharpening

[TropicalSk8ter]

Hey everyone, just wanted to see if you guys knew anything about this new sharpening method.  My pro shop is the one advertising it, but I'm not sure if it's something only for hockey on a count that it was advertised on hockey blades. I don't think it's only for hockey because blades will always be blades.What do you guys think? Here is the link to my pro shop website http://panthersiceden.com/pro-shop/services.html


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[Query]

Apparently hockey teams have enough money to try out lots of new ideas. Quite often manufacturers even give them new equipment to try out, so they can say that the pros have used it.

My understanding was that a lot of pro hockey players tried it (which is enough for the manufacturer to advertise that pro hockey players use it), but relatively few of the pro hockey players embraced it. But that may be wrong - my info came from a hockey pro shop owner who didn't have the appropriate equipment. He claimed the possible advantages - it is a rather small change in the shape of the edge - are outweighed by changes to that shape that occur when hockey players stop very fast or smash their skates into each other.

There are a lot of other things that pro hockey players have similarly experimented with, but most don't use. Like electrically heated blades, and using thin concave instead of thin convex areas on the blade to prevent side-slip.

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As best I understand it, edge shapes are a compromise between two ideas:

1. Allowing a long, fast along-blade glide on the one side. This is best achieved by a flat cross-section - infinite hollow radius.

2. Preventing slide slip, as well as giving you strong pushes and stops. This is best obtained by a very thin sheet metal-like extensions - the "edges" - at the sides of the blade, which cut into the ice to prevent you from sliding sideways, and give you a stronger push, while creating very little drag to sliding along the blade.

These two ideas fight each other.

In a standard hollow cut, as with almost all sharp steel tools, the tip of each edge is essentially a reshaped, polished sharpening burr. Essentially, when you grind a blade, the tip is knocked over to the sides, away from the abrasive grinding surface, by contacts with the abrasive surface. In addition, though this is controversial, the steel may be reshaped to stretch and push out additional metal into that tip, which becomes the "lip" or "sharpening burr". When the sharpener straightens the edge with a fine grained flat grinding stone, it polishes the tip, and reshapes it to point downwards into the ice. The result is extremely thin. Some sharpeners feel it is too thin, and is too different during the first hour or so from remaining hours of use, and deliberately grind off the sharpest part, but there is still a relatively thin part that cuts into the ice. (Reshaping and polishing the edge is commonly called "deburring" - but does not actually remove the burr. However, in some metal shop work, I think "deburring" sometimes refers to removing sharp edges altogether.)

In a flat bottom V, the standard cylindrical concave hollow shape is replaced by a concave V shape. Most of the time, that part has relatively little contact with the ice, and may not be very important, though I can't prove that.

But in a flat bottom V, I think they get rid of the sharpening burr altogether, and grind to shape a much thicker sheet at the sides of the blade. Perhaps that makes some sense for hockey, because hockey players frequently knock down or smash down their edges, which a thicker edge would resist.

But in principle, the thicker that edge, the slower and shorter the glide, because it has more drag in the ice - or you have to push harder to get the same speed. A flat surface hydroplanes over the ice,  which is why speed skates are ground flat across the blade (infinite hollow radius), and also have much less curved rockers.

Thick edges may be OK for some hockey players - players are typically on the ice for maybe 45 seconds at a time, during which they spend a lot of time pushing hard to accelerate and stop. In addition, the typical middle length of a hockey blade has a less curved (longer rocker radius) longitudinal shape than a figure blade, which lets them push harder and stop harder than figure skaters, which is very hard on the edges.

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But that is all theory. I've not tried flat bottom V, and probably not a good enough skater to notice the difference.

But if you try it, tell us how you like it.

At a rink I skate at, in Bowie, MD, the new pro shop managers were sold on the flat bottom V idea, when they bought a new, very expensive sharpening machine made by Blackstone, which I think owns the patents on flat bottom V. I haven't asked any skaters whether they like the flat bottom V, or whether it is only used for the hockey players. I suppose I could.

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Here is Blackstone's link, which includes a description of flat bottom V.

[TropicalSk8ter]

Apparently hockey teams have enough money to try out lots of new ideas. Quite often manufacturers even give them new equipment to try out, so they can say that the pros have used it.

My understanding was that a lot of pro hockey players tried it (which is enough for the manufacturer to advertise that pro hockey players use it), but relatively few of the pro hockey players embraced it. But that may be wrong - my info came from a hockey pro shop owner who didn't have the appropriate equipment. He claimed the possible advantages - it is a rather small change in the shape of the edge - are outweighed by changes to that shape that occur when hockey players stop very fast or smash their skates into each other.

There are a lot of other things that pro hockey players have similarly experimented with, but most don't use. Like electrically heated blades, and using thin concave instead of thin convex areas on the blade to prevent side-slip.

---

As best I understand it, edge shapes are a compromise between two ideas:

1. Allowing a long, fast along-blade glide on the one side. This is best achieved by a flat cross-section - infinite hollow radius.

2. Preventing slide slip, as well as giving you strong pushes and stops. This is best obtained by a very thin sheet metal-like extensions - the "edges" - at the sides of the blade, which cut into the ice to prevent you from sliding sideways, and give you a stronger push, while creating very little drag to sliding along the blade.

These two ideas fight each other.

In a standard hollow cut, as with almost all sharp steel tools, the tip of each edge is essentially a reshaped, polished sharpening burr. Essentially, when you grind a blade, the tip is knocked over to the sides, away from the abrasive grinding surface, by contacts with the abrasive surface. In addition, though this is controversial, the steel may be reshaped to stretch and push out additional metal into that tip, which becomes the "lip" or "sharpening burr". When the sharpener straightens the edge with a fine grained flat grinding stone, it polishes the tip, and reshapes it to point downwards into the ice. The result is extremely thin. Some sharpeners feel it is too thin, and is too different during the first hour or so from remaining hours of use, and deliberately grind off the sharpest part, but there is still a relatively thin part that cuts into the ice. (Reshaping and polishing the edge is commonly called "deburring" - but does not actually remove the burr. However, in some metal shop work, I think "deburring" sometimes refers to removing sharp edges altogether.)

In a flat bottom V, the standard cylindrical concave hollow shape is replaced by a concave V shape. Most of the time, that part has relatively little contact with the ice, and may not be very important, though I can't prove that.

But in a flat bottom V, I think they get rid of the sharpening burr altogether, and grind to shape a much thicker sheet at the sides of the blade. Perhaps that makes some sense for hockey, because hockey players frequently knock down or smash down their edges, which a thicker edge would resist.

But in principle, the thicker that edge, the slower and shorter the glide, because it has more drag in the ice - or you have to push harder to get the same speed. A flat surface hydroplanes over the ice,  which is why speed skates are ground flat across the blade (infinite hollow radius), and also have much less curved rockers.

Thick edges may be OK for some hockey players - players are typically on the ice for maybe 45 seconds at a time, during which they spend a lot of time pushing hard to accelerate and stop. In addition, the typical middle length of a hockey blade has a less curved (longer rocker radius) longitudinal shape than a figure blade, which lets them push harder and stop harder than figure skaters, which is very hard on the edges.

---

But that is all theory. I've not tried flat bottom V, and probably not a good enough skater to notice the difference.

But if you try it, tell us how you like it.

At a rink I skate at, in Bowie, MD, the new pro shop managers were sold on the flat bottom V idea, when they bought a new, very expensive sharpening machine made by Blackstone, which I think owns the patents on flat bottom V. I haven't asked any skaters whether they like the flat bottom V, or whether it is only used for the hockey players. I suppose I could.

---

Here is Blackstone's link, which includes a description of flat bottom V.

From the way that you explain it and theoretically it should be harder to glide on. I do believe it'll most likely be for hockey only. I would ask as well but I'm not going to my pro shop till my boots come in, which should be about a week more supposedly. If they could do it for figure blades then I'll try it when I get my blades mounted.


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[amy1984]

One of the sharpeners in my area has this.  It's for hockey I think.  He doesn't use it on my skates and I've never asked him to.  Some skaters really seem to like it.  But at the same time, I think if it was that amazing, it'd have taken off a bit more.  I'm in a huge hockey market and I only know of one guy who sharpens using it.

And also, as most figure skaters will say, blades are not just blades sharpening for hockey and figure skating are super different.  I can tell when someone who KNOWS figure skates has sharpened my blades, and after years of skating, there's only two or three people in my area that I'd hand my skates off to.

[AgnesNitt]

This reminds me of the discussion about parabolic blades. Some people love them and others are like meh.

[Query]

BTW - My whole speculation on flat bottom V is speculation. I have not tried such edges.

For example, maybe I am totally wrong about the V-shaped hollow cross section being little different than the usual circular cross section hollow.

In particular, it is very possible that figure skaters skate as much against the hollow as against the sides of the blade (which would make the edge a keel rather than a side board, in boating terms, because it is in the middle of the area of contact). In that case a flat, uncurved hollow, such as a flat bottom V might hydroplane better, and create less drag, which might make up for the thicker edge.

I What would be fun is if someone were to try them, and compare them to regular edges created by the same sharpener.

But amy1984's point is good too. Hockey blades are thinner than figure skate blades, the profile is a lot different. Maybe a flat bottom V sharpening device wouldn't produce proper edges or would mess up the toe pick or tails on figure skate blades, or otherwise alter the profile. It would be a good idea to call Blackstone first, and ask if it makes sense.

[TropicalSk8ter]

BTW - My whole speculation on flat bottom V is speculation. I have not tried such edges.

For example, maybe I am totally wrong about the V-shaped hollow cross section being little different than the usual circular cross section hollow.

In particular, it is very possible that figure skaters skate as much against the hollow as against the sides of the blade (which would make the edge a keel rather than a side board, in boating terms, because it is in the middle of the area of contact). In that case a flat, uncurved hollow, such as a flat bottom V might hydroplane better, and create less drag, which might make up for the thicker edge.

I What would be fun is if someone were to try them, and compare them to regular edges created by the same sharpener.

But amy1984's point is good too. Hockey blades are thinner than figure skate blades, the profile is a lot different. Maybe a flat bottom V sharpening device wouldn't produce proper edges or would mess up the toe pick or tails on figure skate blades, or otherwise alter the profile. It would be a good idea to call Blackstone first, and ask if it makes sense.

I asked my pro shop if they could sharpen my blades with that machine and they told me that it's only for hockey.


Ripping the ice all day!