Author Topic: Parabolic blades???  (Read 222 times)

ItsEllieJane

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Parabolic blades???
« on: November 01, 2018, 01:16:45 PM »
I'm about to get some new boots because mine are pretty naff. So I need to get some new blades too. I'm thinking about getting the coronation ace, but what's the difference between the normal and parabolic ones, and is it worth it???

spinZZ

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Re: Parabolic blades???
« Reply #1 on: November 02, 2018, 05:54:30 PM »
Refer to the attached drawing, which shows bottom views of the blade edges (i.e., turn your skates such that the top of the boot is pointed straight down and the blade edges are pointed straight up; and look down on the edges).  The drawing is not to scale; certain features have been exaggerated to make them more visible.

(a) A standard Coronation Ace has a parallel edge geometry.  The inside edge and the outside edge both have straight-line geometries; the sides of the blade are ground flat  The inside edge is parallel to the outside edge along the entire length of the blade from toe to heel.  The thickness of the blade is constant along the length of the blade.

(b) A parabolic Coronation Ace has a parabolic edge geometry.  The inside edge and the outside edge both have curved-line geometries; the sides of the blade are side-honed concave [the side-honing by itself yields different edge properties than those of the standard Coronation Ace, but I won't go into those details].  The thickness of the blade is greater at the toe and the heel than at the center of the blade.  If the blade is ground with a constant radius of hollow (ROH), the bite angle of the edges depend on the thickness of the blade:  the edges have more bite at the toe and the heel than at the center.  Since glides are done near the center of the blade, less bite gives smoother glides.  Since turns are done near the toe or the heel of the blade, and spins and jumps are done near the toe of the blade, more bite gives better control.  Anyway, that's how it works in theory.  But since the Coronation Ace is an intermediate blade, I don't think it's worth it; though I personally have not tried a parabolic blade myself.  Also note that it's difficult to check the quality of sharpening (depth of hollow and evenness of edges) for a parabolic blade.
« Last Edit: November 02, 2018, 08:42:30 PM by spinZZ »

spinZZ

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Re: Parabolic blades???
« Reply #2 on: November 02, 2018, 05:58:22 PM »
(delete duplicate)

Crackers

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Re: Parabolic blades???
« Reply #3 on: November 02, 2018, 10:28:32 PM »
Refer to the attached drawing, which shows bottom views of the blade edges (i.e., turn your skates such that the top of the boot is pointed straight down and the blade edges are pointed straight up; and look down on the edges).  The drawing is not to scale; certain features have been exaggerated to make them more visible.

(a) A standard Coronation Ace has a parallel edge geometry.  The inside edge and the outside edge both have straight-line geometries; the sides of the blade are ground flat  The inside edge is parallel to the outside edge along the entire length of the blade from toe to heel.  The thickness of the blade is constant along the length of the blade.

(b) A parabolic Coronation Ace has a parabolic edge geometry.  The inside edge and the outside edge both have curved-line geometries; the sides of the blade are side-honed concave [the side-honing by itself yields different edge properties than those of the standard Coronation Ace, but I won't go into those details].  The thickness of the blade is greater at the toe and the heel than at the center of the blade.  If the blade is ground with a constant radius of hollow (ROH), the bite angle of the edges depend on the thickness of the blade:  the edges have more bite at the toe and the heel than at the center.  Since glides are done near the center of the blade, less bite gives smoother glides.  Since turns are done near the toe or the heel of the blade, and spins and jumps are done near the toe of the blade, more bite gives better control.  Anyway, that's how it works in theory.  But since the Coronation Ace is an intermediate blade, I don't think it's worth it; though I personally have not tried a parabolic blade myself.  Also note that it's difficult to check the quality of sharpening (depth of hollow and evenness of edges) for a parabolic blade.

Nice explanation Spinzz :)

My 2 were advised against getting parabolic blades by their coach (& others) so we ended up getting Standard Coronation Ace for Son on Jackson Premiere (feet still growing) and Standard Revolution Coronation Ace for Daughter on Edea Ice Fly.
The Revolution Coronation Ace blade is the same profile as the Standard but more expensive (about 175 per pair in March 2018) and soooo much lighter than the standard Coronation Ace due to the Carbon Fibre mounts.  It is a good pairing with the lightweight Ice Fly.

Both love their blades and they hold a 7/16" ROH edge for quite a bit longer than the Mirage & Rotation blades they had before on their previous boots.  So potentially less sharpening depending on how often you skate.

Hope this helps