Author Topic: Sharpening life  (Read 108 times)

Rachelb

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Sharpening life
« on: April 30, 2019, 02:38:37 PM »
Does anyone know how to judge how much sharpening life a blade has? Is there a key point at which they are no good? My daughter has a pair of 2nd hand boots and the boots themselves are fine with enough support etc but the blades do seem well used and I'm wondering if they are no longer any good. The rocker is certainly flatter than on my own boots but then im comparing different blades and sizes. I just don't want her to be on the ice if they are no good and going to hinder her.

transmissionoftheflame

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Re: Sharpening life
« Reply #1 on: April 30, 2019, 08:22:59 PM »
Whoever sharpens your skates ought to know.  Otherwise I think it's a question of feel.  Mine are getting pretty flat, so I find I am more stable but maybe catch an edge more often in spins.  Turns seem fine.  My daughter and her coach skated on absurdly flat skates for ages and did so without difficulty - but they have a good deal more skill than I do.  There'll come a point where they no longer work well.  If you are a good skater aware of what's happening then you'll feel when that moment comes.  Trickier if you're a relative beginner.  I think there are some experts in this sort of thing on the forum so hopefully they can give some scientific way to measure it...

Weeyin

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Re: Sharpening life
« Reply #2 on: April 30, 2019, 08:31:24 PM »
I read your reply there with interest. My skates are probably about due a sharpen. I like them to be done regularly as I like the feel of sharp blades. But the last few sessions my spins have gone, always seem to, and I like how you describe it, “catch an edge”. I feel that I’m doing everything as normal and yet the back inside edge seems to get the ice and I either do a big inside edge circle or I almost go over my heel. I’m wondering if that is a sign that I need a sharpen.

spinZZ

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Re: Sharpening life
« Reply #3 on: April 30, 2019, 08:37:46 PM »
There are two principal considerations that determine sharpening life:

(1) Amount of hardened and tempered steel.  Typically the entire blade is not hardened and tempered; only a zone near the edges.  For traditional chrome-plated carbon steel blades, this zone is demarcated by the chrome relief:  the shiny, polished chrome is removed in a zone along the edges, leaving a duller, rougher steel surface.  This zone indicates the region that is properly hardened and tempered:  if you sharpen below this zone, the steel becomes softer and won't hold an edge well.

For some stainless-steel blades (which have no chrome plate and, hence, no chrome relief), such as the Eclipse Aurora, the hardened and tempered zone is marked with a scribed line.

(2) Heel lift.  See the Paramount video https://www.paramountskates.com/videos "Lift Angles".  As the blade is repeatedly sharpened, the depth of the edge below the drag pick increases, the sweet spot moves back, and the heel lift decreases.  This makes it harder to do a scratch spin.  If you purchased a blade new, you can measure the initial heel lift and measure the decrease after repeated sharpenings.  With a used blade, of course, you don't know what the initial heel lift was:  it varies with the model of blade.  The video mentions a "wellness gauge"  that measures when the blade can be repaired to increase the heel lift, or discarded.  The problem is that the gauge is nominally calibrated for Wilson and MK blades.  Other manufacturers, such as Ultima and Eclipse, tend to have flatter initial spin rockers.  If your daughter is working on spins, the blade most likely will need to be replaced before the hardened and tempered zone is used up.  Note that even with a new blade, just one bad sharpening can destroy the spin rocker (or other portion of the blade).  This makes buying used blades iffy.
« Last Edit: April 30, 2019, 08:50:10 PM by spinZZ »