Sharpening zone on blades

Curlygirly81 · Jan 2, 2019

I've always skated in coronation aces. I purchased and mounted a legacy 8 blade to a new boot to teach in thinking I'd try something new with an 8" rocker.
I also have brand new aces on my other boot.
When I look at both blades (aces vs legacy) I noticed the "sharpening zone". (Matted area of the blade) Is much less on the legacy. Both blades are new and have one sharpening.
So I'm thinking I'll get less sharpenings from the legacy. Is this common with Ultima blades? Does it have to do with the rocker?

Thanks for any feedback.

jf12 · Jan 3, 2019

Curlygirly81 said:
I've always skated in coronation aces. I purchased and mounted a legacy 8 blade to a new boot to teach in thinking I'd try something new with an 8" rocker.
I also have brand new aces on my other boot.
When I look at both blades (aces vs legacy) I noticed the "sharpening zone". (Matted area of the blade) Is much less on the legacy. Both blades are new and have one sharpening.
So I'm thinking I'll get less sharpenings from the legacy. Is this common with Ultima blades? Does it have to do with the rocker?

Thanks for any feedback.

I think the sharpening zone is a myth. All of my blades have been done before running out of room on the matte part.

tstop4me · Jan 3, 2019

Curlygirly81 said:
I've always skated in coronation aces. I purchased and mounted a legacy 8 blade to a new boot to teach in thinking I'd try something new with an 8" rocker.
I also have brand new aces on my other boot.
When I look at both blades (aces vs legacy) I noticed the "sharpening zone". (Matted area of the blade) Is much less on the legacy. Both blades are new and have one sharpening.
So I'm thinking I'll get less sharpenings from the legacy. Is this common with Ultima blades? Does it have to do with the rocker?

Thanks for any feedback.

The entire body of the blade is not hardened and tempered; only a zone along the edges. On carbon steel blades, the body of the blade is plated to provide rust resistance and to give it a shiny finish. The plating is removed along the edges to expose the hardened and tempered steel zone, providing more uniform material for more uniform edges. Removal of the plating creates the matte-finish region, often called the chrome relief (though more than chrome is usually involved in the plating process). The manufacturer provides some margin (taking into account variations in the process used for removing the plating), so the hardened and tempered region will typically extend somewhat below the chrome-relief boundary. Rocker radius is not a factor per se. Manufacturers set different design targets for their blades.

In practice, for intermediate and advanced figure skating blades, blade life will likely be limited by flattening of the spin rocker before you exhaust the hardened and tempered region. Also, blade life will depend on the edge retention of the particular steel (which depends not only on the composition of the steel, but on the specific thermal and mechanical processing used by the blade manufacturer): better edge retention translates to fewer sharpenings for a given amount of ice time. So the depth of the chrome relief is only one factor, out of several, that determines the overall service life of the blade.

ETA: Just curious, how much difference is there? Measurements will typically vary along the blade. If you take a measurement near the center of the blade, what are the depths of the chrome relief for your two blades?

Nimyue · Jan 3, 2019

Curlygirly81 said:
I've always skated in coronation aces. I purchased and mounted a legacy 8 blade to a new boot to teach in thinking I'd try something new with an 8" rocker.
I also have brand new aces on my other boot.
When I look at both blades (aces vs legacy) I noticed the "sharpening zone". (Matted area of the blade) Is much less on the legacy. Both blades are new and have one sharpening.
So I'm thinking I'll get less sharpenings from the legacy. Is this common with Ultima blades? Does it have to do with the rocker?

Thanks for any feedback.

Ultima blades are notoriously flat. They don't come with much spin rocker, so if that's what you're seeing it makes sense. Pictures might help though.

mystery905 · Jan 3, 2019

Nimyue said:
Ultima blades are notoriously flat. They don't come with much spin rocker, so if that's what you're seeing it makes sense. Pictures might help though.

I compared Legacy 7 with Coronation Ace and the profiles were almost identical. FYI

tstop4me · Jan 3, 2019

Nimyue said:
Ultima blades are notoriously flat. They don't come with much spin rocker, so if that's what you're seeing it makes sense. Pictures might help though.

The chrome relief along the spin rocker is often non-uniform. You get a better comparison along the main rocker.

SmallAminal · Jan 6, 2019

tstop4me said:
In practice, for intermediate and advanced figure skating blades, blade life will likely be limited by flattening of the spin rocker before you exhaust the hardened and tempered region.

Tstop - it seems you are very knowledgeable about this, so I wanted to ask about how you actually know when your blades are "dead". For example, my skater is in Coronation Aces - for a while, we would go through the skates so quickly that we had to move up a blade size before they were "dead". However, my skater realized a drastic improvement in performance when switching to new boots and new Coronation Aces after having been in ones that were sharpened almost to the end of the chrome relief.

I was told at the figure skating specialist store that the blade still has "life" until you are completely through the chrome relief section. However, you are saying that the blade is dead when you have flattened the spin rocker. Can you explain exactly what you mean by that? We check the profile of the skates before/after sharpening using this weird tool my husband has (it has pins that you push along the edge of something to measure the profile) and even though we are almost through the chrome relief, the profile does not appear to have changed. However, since the blade is "shorter" from all of the sharpenings, you have a shorter distance between the tail and the ground when you rock up to the pick than a brand new blade. Is this what you mean by "flattening of the spin rocker"?

Although the blades still had some chrome relief left in them, I noticed that our sharpener had ground off a tiny bit of the drag pick on each blade, presumably so my skater was not skating on the pick the whole time. My skater complained that the blades were "no good" and insisted I change them to fresh ones. I'm wondering if there is something to this, especially since the spins have been harder lately (but hard to say because we missed 6 weeks with an injury).

Ic3Rabbit · Jan 6, 2019

I'll let tstop4me give you more detail and from their knowledge.

But I think the whole "chrome" wear story isn't always the way to assess things.

To Test your rocker find a smooth flat surface and rock your blade from toe to heel and then over again. The blade should rock from it's point of contact behind your toepick to at least the first part of the blade heel stanchion evenly and with smoothness. If it doesn't do so then that means there is a flat spot or worse. A blade that does this will make it go straightforward on the ice with no natural curve, you would need new blades.

I hope this helps.

tstop4me · Jan 8, 2019

SmallAminal said:
Tstop - it seems you are very knowledgeable about this, so I wanted to ask about how you actually know when your blades are "dead". For example, my skater is in Coronation Aces - for a while, we would go through the skates so quickly that we had to move up a blade size before they were "dead". However, my skater realized a drastic improvement in performance when switching to new boots and new Coronation Aces after having been in ones that were sharpened almost to the end of the chrome relief.

I was told at the figure skating specialist store that the blade still has "life" until you are completely through the chrome relief section. However, you are saying that the blade is dead when you have flattened the spin rocker. Can you explain exactly what you mean by that? We check the profile of the skates before/after sharpening using this weird tool my husband has (it has pins that you push along the edge of something to measure the profile) and even though we are almost through the chrome relief, the profile does not appear to have changed. However, since the blade is "shorter" from all of the sharpenings, you have a shorter distance between the tail and the ground when you rock up to the pick than a brand new blade. Is this what you mean by "flattening of the spin rocker"?

Although the blades still had some chrome relief left in them, I noticed that our sharpener had ground off a tiny bit of the drag pick on each blade, presumably so my skater was not skating on the pick the whole time. My skater complained that the blades were "no good" and insisted I change them to fresh ones. I'm wondering if there is something to this, especially since the spins have been harder lately (but hard to say because we missed 6 weeks with an injury).

(1) The chrome relief sets a nominal maximum depth that can be sharpened. As long as you stay within the chrome relief, the steel is properly hardened and tempered. If you sharpen much below the chrome relief (depending on the margin provided by the manufacturer), you will hit into soft steel that won’t hold an edge for long. In that sense, when you exhaust the chrome relief, the blade is “dead”.

(2) Even within the chrome relief, however, sharpening changes the overall blade geometry. The blade is not “dead” per se, but gradual changes in the overall blade geometry result in gradual degradation in performance. How severe the degradation in performance is depends on the maneuver. How much degradation in performance is acceptable depends on the individual skater. This issue is similar to the oft-discussed issue of how frequently blades should be sharpened: some skaters sharpen frequently to maintain their edges very sharp; others are content to let their edges go dull before they go for a sharpening.

(3) If you want blades for simple stroking (e.g., for skating around a pond), then you can indeed sharpen the blades until the chrome relief is exhausted. For more advanced maneuvers, however, you need to be aware of the changes in the overall blade geometry. Here, I mean changes that result as a matter of course from ideal sharpening. In practice, however, repeated sharpenings, even by a good tech, will produce further changes.

(4) One obvious change as a result of multiple sharpenings is a reduction in blade height: the height between the mounting plates and the edges decreases. This is equivalent to a lower stanchion height.

(5) A more subtle change, but one with more pronounced consequences, is a change in the drag-pick/spin-rocker geometry. I will need to create drawings to explain this more clearly, but I’m not sure when I’ll have time to do that. Here’s a basic explanation:

(a) Find a flat surface. Check it with a straight edge to confirm that it’s flat. Tape a sheet of paper on the flat surface to protect it or the blade.

(b) Assume that the sheet of paper corresponds to a sheet of ice. Position the skate blade on the paper in a skating position: boot pointed up; blade down against the paper; toe pointing left. Look from the side of the blade, and view the edge facing you.

(c) Rock the blade forward until the drag pick just touches the paper. Ideally [more on this later; see the caveat in (f) below], the blade will touch the paper at one other point on the spin rocker. Mathematically, this is the tangent point. It is approximately equal to the sweet spot in a scratch spin. Under real skating conditions, of course, both the drag pick and the edges cut into the ice, and the scenario is more complex; but this is a good approximation. Using a pencil, mark the positions of the drag pick and the tangent point on the paper. Using a ruler, measure the distance between the drag pick and the tangent point.

(d) As you grind the blade down through repeated sharpenings, the edge gets raised with respect to the drag pick. If you repeat step (c), you will find that the distance between the drag pick and the tangent point increases: the sweet spot moves further back from the drag pick. If the sweet spot moves back sufficiently, it will affect your scratch spin (and other moves that depend on the picks and spin rocker).

(e) It is possible to move the tangent point forward again by trimming the drag pick. This by itself will also decrease the height of the drag pick. A standard sharpener cannot sharpen right up to the drag pick: there is a zone immediately behind the drag pick that the grinding wheel cannot reach because the drag pick gets in the way. Some techs have a cross grinder that can sharpen in this zone and restore the height of the drag pick. Of course, there’s a limit to how much you can modify the drag pick, because the geometrical relationship of the drag pick to the other picks gets altered. (And, the geometrical relationship of the other picks to the blade edges gets altered with repeated sharpenings.) So at some stage, you need to leave the drag pick alone, and the tangent point (and sweet spot) continues to move back with further sharpening. At some point, the skater will decide that performance has degraded too much. Time to replace the blade. As mentioned above, there is no hard limit here; just as there is no hard limit on when to sharpen a blade.

(f) Return to step (c). In practice, it is extremely difficult to identify a single tangent point. If you look closely at the spin rocker resting on the paper, you will more likely see the spin rocker touching the paper along a line segment, whose length depends on the spin rocker. An easier measurement to use to track a key change in the overall blade geometry is the heel lift height. Again, rock the blade forward until the drag pick just touches the paper. Using a ruler, measure the vertical height between the paper and a reference point along the edge near the tail of the blade. Ideally, you can take the measurement at the very tail of the blade. Often, however, the tail gets rounded after repeated sharpenings; so measure the height at a point on the edge, e.g., 5 mm in front of the tail. Measure this height when the blade is new, and record the value. Repeat the measurement after each sharpening. This height will gradually decrease with repeated sharpenings. Track drops in performance, and record what the height is. Assuming you continue to use the same model and size of blade, you can use these measurements to give you a rough estimate of when to modify the drag pick and when to get a new blade [that is, when to take action before noticeable degradation in performance occurs on your next blade].

Curlygirly81 · Jan 8, 2019

Thanks for the tips everyone!

SmallAminal · Jan 9, 2019

TStop that was incredibly detailed information! Very helpful and confirms what I suspected - I did my own version of the heel lift check earlier (comparing the new blade to an old one) and had observed a visible difference in the distance to the table. I guess my skater's complaints about performance were valid even though there was some sharpening left in the blade

It is curious to me that blade manufacturers don't give you "instructions" with your blades or at least educate the retailers so that they are not perpetuating the myth that the blade is "fine" until you sharpen past the chrome relief.

Ic3Rabbit · Jan 9, 2019

SmallAminal said:
TStop that was incredibly detailed information! Very helpful and confirms what I suspected - I did my own version of the heel lift check earlier (comparing the new blade to an old one) and had observed a visible difference in the distance to the table. I guess my skater's complaints about performance were valid even though there was some sharpening left in the blade

It is curious to me that blade manufacturers don't give you "instructions" with your blades or at least educate the retailers so that they are not perpetuating the myth that the blade is "fine" until you sharpen past the chrome relief.

Ic3Rabbit said:
I'll let tstop4me give you more detail and from their knowledge.

But I think the whole "chrome" wear story isn't always the way to assess things.

To Test your rocker find a smooth flat surface and rock your blade from toe to heel and then over again. The blade should rock from it's point of contact behind your toepick to at least the first part of the blade heel stanchion evenly and with smoothness. If it doesn't do so then that means there is a flat spot or worse. A blade that does this will make it go straightforward on the ice with no natural curve, you would need new blades.

I hope this helps.

Like I said previously, the chrome wear story is a myth.

SmallAminal · Jan 10, 2019

Ic3Rabbit said:
Like I said previously, the chrome wear story is a myth.

I think we all agree on that.

My point is that it is surprising that the manufacturer`s don`t include detailed care and sharpening instructions with the blades. It would be to their advantage to do so because people might replace their blades sooner if they were aware. The fact that a well-known retailer in my area is telling me that you base it on the chrome relief shows me how little even certain ~experts~ know about this.

Sharpening zone on blades

Curlygirly81

jf12

tstop4me

Nimyue

mystery905

tstop4me

SmallAminal

Ic3Rabbit

Former Elite, now Pro. ⛸️

tstop4me

Curlygirly81

SmallAminal

Ic3Rabbit

Former Elite, now Pro. ⛸️

SmallAminal

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