Having lots of slippage after a sharpening. Is 5/8" roh OK?

[eillie]

I sharpened my blades earlier this week and immediately thought that they didn't feel as 'sticky' on the ice as I would've expected for newly sharpened skates.  This resulting in me having both random falls doing things I normally don't have problems with (sliding and falling sideways doing forward crossovers!) and also more issues than usual with things I am still learning.  The biggest thing I noticed was that my loop jump (which I'm still beginning to learn) felt a lot harder ... I've learned the entry from a forward inside 3-turn, and immediately after the 3-turn I kept skidding.  On the bright side, my backward outside 3-turns felt easier because of the slipperiness!  (Probably not how it's suppose to be done, but oh well.)  Overall though, I am not very happy with the change in how the blades feel.   


I don't know very much about the technical details of blades, but I asked the sharpener what the radius he was using was, and he said it was around 5/8".  Unfortunately I don't know what radius I had before the sharpening, because my skates are new and they came sharpened already.


My question is, is 5/8" normal for a beginner?  A bit of googling seems to indicate that 1/2" is more common, but is 5/8" still reasonable?


I think I just want to know whether I should suck it up and work harder  , or if this is a blade problem and I need to get it fixed soon.

[sarahspins]

5/8" would have me skidding all over the place.  My blades are sharpened just a hair deeper than a 3/8" ROH... but I like my blades to be extra grippy (and it doesn't for me mean a decrease in glide - we had a "one push, see how far you can glide" contest a while back in our figure class and I was the only one able to push/glide further than the coach teaching the class).

Back in late Feb or early March of this year though I had them sharpened leading up to a test session and my sharpener accidentally put a shallower hollow on my blades than I am used to - and I couldn't skate at all.  I went from knowing my blades needed sharpening, to basically being unable to skate because I effectively had no edges.  He fixed them for me the next time I saw him, and apologized profusely for the mistake.

If you are struggling with it, I'd take them back to the sharpener and request that they be done a little deeper (and IMO you shouldn't be charged for a "correction" like that).  1/2" and 7/16" are both commonly used... I wouldn't go deeper unless you know you need it.

[FigureSpins]

First point: A factory sharpening is rarely decent; it's really just intended to let you try out the blade alignment.  It's typically uneven and inadequate for regular skating.  I assume you mean that you had them sharpened professionally when you bought them, if you were doing turns and Loop jumps on new skates.

My other point: you're not a beginner.  You're doing three turns, loop jumps and spins.  You're a low-level freestyle skater.  To that end, a 1/2" or 5/8" ROH is fine.  5/8" is pretty close to a 1/2", but if you feel like you're slipping off the edges, that's a problem.  He may have guessed wrong.  I use a 3/8" ROH because the 1/2" makes me feel like I'm skating sideways on every edge.  I'm sure that 5/8" would leave me unable to skate. 

I don't know very much about the technical details of blades, but I asked the sharpener what the radius he was using was, and he said it was around 5/8".  Unfortunately I don't know what radius I had before the sharpening, because my skates are new and they came sharpened already.

You paid him to sharpen your blades and he doesn't know what radius he used?  He's guessing that it's "around 5/8"?"  Check to make sure your rocker and tail edges are intact on your new blades because he sounds careless.  You could always take the skates into the shop and ask him to measure the ROH.  There's a tool that good sharpeners use to check the blade hollow and depth.  They also check for evenness of edges. 

ETA: Found the penny-measurement trick.  It's on this page: http://www.thebladedoctor.com/skatefacts.html

Here's my guess: you had the skates sharpened professionally when you bought them.  The sharpener probably used 1/2" roh.  On this sharpening, you said that you were "a beginner," so he put a beginner's 7/16" or 3/8" roh on the blades.  That's much more shallow and explains why you're sliding out on edges.

If he's the only game in town, take them back and have him fix the error.  ITA that there shouldn't be a charge for the correction.  If he gets defensive or nasty, find a new sharpener.

[sampaguita]

I have difficulty with edges on a 1/2" ROH. I would not skate on a 5/8" ROH.

If you're having difficulty with your edges and the blades don't feel grippy enough, then you have to change the ROH. You might be able to adjust to the new ROH, or you might not -- but if your sharpener will re-sharpen the blades free of charge, just get them re-sharpened.

[Query]

What type of blade do you have? We can maybe look up the factory sharpening, though FigureSpins is right - the seller might have re-sharpened it without asking.

ROH isn't the only determinant of sharpness. You can also be keen - i.e., there is a abrupt rather than rounded direction change at the tip. And the very tip of the blade can be longer. A lot of people think sharpness is only determined by ROH, because the picture the edge as being produced by the angle between the sides of the blade and the hollow curve. But sharpening initially knocks down the tip of the edge, so the keenness and length of edge aren't exclusively determined by hollow. That depends on how coarse the wheel is, how much metal the sharpener removes, and I think maybe how slowly and carefully the sharpener works. Then the sharpener pushes the edge back upright or slightly inwards with a flat stone.

In some cases the sharpener then deliberately dulls the edge a bit, making it less keen and/or reducing the tip length, because many skaters don't like extremely sharp blades, and many skaters step off ice before putting on their skate guards, or stop hard, either of which would knock the tip of the edge sideways or inwards if it was very sharp.

Carefully (don't cut yourself) run your finger along the edge, on the bottom, at the sides, and inside the hollow. If the sharp part doesn't point downwards, you have knocked your edge sideways, but it is still there. You can push it back upright with a piece of hard leather, or a rubber stone. (Most people don't do that - they just re-sharpen if anything goes wrong - but I think they use up their blades faster than they have to.)

If there is no really sharp part - your sharpener deliberately dulled the edges, or used a very coarse grinding wheel.

It's important to tell a sharpener that you want a sharp edge if you like sharp, so the sharpener won't dull the edge much if at all after sharpening, and may PERHAPS use a finer grinding wheel - if you are willing to take very good care of your blades and never step without guards off-ice.

BTW, I happen to use a smaller ROH - 3/8". I think 7/16" is most common around here, but I've met good skaters, including some coaches, who make do with larger, like 3/4", because the edge is supposed to last longer. There is no universal standard here.

[Qarol]

Fascinating. I'm so happy I found this info. I do like it when my blades are sharp, but lately, after sharpening, they don't feel all that different. I do know I get a 1/2" hollow so maybe I'll try a 3/8" and see how I like it. Or make sure they're not dulling the blade after sharpening.

[Query]

There is no really standard material on how sharpening works. You will find contradictory information from different sources. I probably should have made it more clear that not everyone agrees with what I said.

[icedancer]

I would just take them back and say they are slipping.  If you are used to a .5 hollow then you will probably feel better with that.  3/8 may be too deep for you... I know it was for me...

[FigureSpins]

For once, I agree with Query.  I think the sharpener didn't check the setting.  It's probably more shallow than a 1/2".  As I suggested before,have him check the roh before doing anything.

[eillie]

Thank you so much to everyone's replies and advice--they were very helpful.  I can add a few things:

One is that I am pretty sure the sharpener mentioned to me that he could tell by eye what the roh was, so I figured he had eyed it and would grind it to match what I already had, but maybe he mis-estimated it.  After grinding it, he checked that the edges were even by putting a little block on the blade that had a metal bar perpendicular to the blade.  After that, he used some kind of small wet rectangular block and rubbed the blade with it after using the grinding wheel--I'm assuming this is when the edges were dulled a little bit to make the blade less 'keen'.


My blades are Ultima Mirage ones, and I believe the shop owner sharpened it for skating before I took them home, but I didn't ask what the roh was.


I just checked the blade profile by putting each skate on a flat surface and tilting it towards the toe until the toe-pick stopped it from going further.  It seems I still have a rocker, I think.

Whether the slipperiness I'm feeling is due to the roh or the keenness, I'm not sure.  (I tried feeling for the edge with my fingers, and it feels scrape-y like a sharp edge is there, so I'm leaning towards the problem being the roh.)   I wouldn't mind trying a different sharpener, but my options are quite limited, so I'll probably go back to same one and ask for it to be resharpened to 1/2" with less dulling using the block thing afterwards.  I'll post again with the results!

[sarahspins]

After that, he used some kind of small wet rectangular block and rubbed the blade with it after using the grinding wheel--I'm assuming this is when the edges were dulled a little bit to make the blade less 'keen'.

Not necessarily.  When metal is sharpened on a grinding wheel, a "burr" is left behind adjacent to the new freshly sharpened edge.  Using a stone removes this burr, which would interfere with your skating causing a lot of drag in the ice.  There are some people who may incorrectly state that they are removing the freshly sharpened edge when they stone the blades post-sharpening, but as long as the stone is held reasonably parallel to the side of the blade that will not happen.

[CrossStroke]

Here's my guess: you had the skates sharpened professionally when you bought them.  The sharpener probably used 1/2" roh.  On this sharpening, you said that you were "a beginner," so he put a beginner's 7/16" or 3/8" roh on the blades.  That's much more shallow and explains why you're sliding out on edges.

Just a note: 7/16" or 3/8" (6/16") is deeper than 1/2" (8/16"), and feel "stickier" or "grabbier".  5/8" (10/16") is shallower.
Numbers probably just got inadvertently reversed?

I use 3/8" to 7/16" as well, but there are some forum members who do prefer shallower ROH.

[Query]

When metal is sharpened on a grinding wheel, a "burr" is left behind adjacent to the new freshly sharpened edge.

BTW, the "burr" is what I called the knocked down tip of the edge.

According to several WWW sources, the Mirage ROH is 1/2" at the factory. A good starting point.

Try this: Use or borrow a big set of socket wrenches, which are cylindrical on the outside. Find the one that fits inside the hollow he cut, as closely as possible. Measure the outer diameter of that socket (ignore the number marked on the socket - it relates to something else).  Divide by 2 to get ROH.

[FigureSpins]

I've never heard of a burr being called a "knocked down tip of the edge."  I had no idea what you were talking about upthread, so next time, just call it a burr.

A burr is a tiny, sharp bit of metal left over from the sharpening.  When you run your finger along the edges, you can feel them.  Typically, they come off/wear down just from skating.  Some sharpeners will remove them as part of their service. ymmv

The default ROH for the Ultima Mirage is 7/16" according to rec-skate.  Since the OP was able to skate well on the blades, I assume the seller had them sharpened at 1/2"

[FigureSpins]

Just a note: 7/16" or 3/8" (6/16") is deeper than 1/2" (8/16"), and feel "stickier" or "grabbier".  5/8" (10/16") is shallower.
Numbers probably just got inadvertently reversed?

Yes, thanks.  I meant 5/8" not 3/8" - always get the fractions mixed up, sorry.

[eillie]

I went back to the sharpener and requested a 1/2" roh, which he was happy to adjust for me free of charge.  They felt a *lot* better immediately, in that I felt I could trust my edges more!  But it still didn't feel how I remembered them being after the first sharpening.  I'll probably be going back in a few weeks though to touch them up, and I'm debating whether I'd like to experiment with 7/16" at that point.


And yes, I remember now that a while back the same sharpener explained that the block thing was for getting rid of burrs!  I once had skates sharpened (elsewhere, with different blades) that made me feel like my blades were completely glued to the ice, and not in a good way.  I actually slammed into the rink wall because I couldn't turn my feet to stop in time!

[sampaguita]

On moving to a deeper hollow: I shifted from 7/16 to 3/8. At first, I was like, "what have I done?" Edges were really slow and I felt like my skates were glued to the ice. 10 minutes later, I was like, "wow edges are a LOT easier!"

[Query]

I figured many people wouldn't know what a "sharpening burr" is.

If you look at the end of a steel edge created by grinding steel on one side under a microscope, you can see that it is bent over to form what people call the "lip" or "burr". It's produced because steel is flexible and deformable, from the pressure of the grinding stone. It is possibly added to by other forms of metal deformation, and is sometimes a bit ragged. (That why when you sharpen knives on a stone, you stroke on alternate sides, and stroke lightly at the end - to place the edge back into the center.)

There seems to be fairly good agreement in a wide variety of sources on sharpening steel tools, that if you actually cut off the burr, or completely grind it off, you end up with something that isn't sharp.

I don't know of any professional skate sharpeners who don't routinely slide a flat stone or something equivalent along the side of the blade after sharpening. That doesn't grind off the burr - it bends it straight (more or less). The precise way in which they do this, the tool(s) they use, the exact angle at which they reshape the burr (it's not uncommon to bend it a bit inward, towards the center of the hollow), and how much of the burr they retain, varies a bit from one sharpener to another, but I've never seen one not do it. In a skate sharpening context, that is what is called "deburring" - but it actually mostly just bends the burr into a straighter edge, and possibly polishes it as well, rather than fully removing the burr.

If you wanted to actually remove the burr, you could instead use a high speed fine grit grinding tool held along the side, or maybe a very sharp razor blade - but you wouldn't like the result if you want clean edges. (A small minority of speed skaters do that, BTW, though none of the ones I've talked to who do their own sharpening. It perhaps yields a very efficient glide, but not so strong a push.)

[icedancer]

There is one sharpener in our area that doesn't necessarily remove the "burr" so I have been known to do it myself on a nearby wooden bench at our rink.

I don't know why people are so afraid of doing stuff like that - it is WAY easier than driving all the way back to the sharpener to get it done by them@

[Query]

There is one sharpener in our area that doesn't necessarily remove the "burr"

Does he/she leave the blade too sharp for you, or is there actually something sharp sticking out to the sides?

If the latter, it must be hard for him/her to keep repeat business.

[icedancer]

Does he/she leave the blade too sharp for you, or is there actually something sharp sticking out to the sides?

If the latter, it must be hard for him/her to keep repeat business.

I don't feel the "burr" - the edges are just extra sticky - he gets a lot of business but is not the BEST in our area (supposedly) - I have mentioned to him that I like for him to take off the burr and he says that some people like it with the burr.

Whatever.  We are somewhat at the mercy of the sharpeners in our respective areas aren't we?

This is why I have been known to just take it off myself with a stone or the edge of a wooden bench.

[Query]

To the original poster: Those of us using Dance blades that are ground thinner near the bottom need a smaller ROH. You aren't on that type of blade. 3/8" may be too small for you.

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IceDancer: We aren't completely at the mercy of local professional sharpeners. It isn't impossible to learn to do it yourself. Good purpose-built hand tools to do it right, and a few extra tools which help, cost a bit over $100 in the U.S. A bit more if you get too curious and want to experiment. (There is a significant learning curve, a possibility for error, a need for hand-eye coordination, and you should be safety conscious.) It's worth it for some people, especially if their pro sharpener isn't where they skate, or they are unhappy with the results. But it sounds as if your major issue with your pro is one that you have learned to fix, so it might not be worth it for you.

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On the matter of dulling the edge:

I used to love extra sharp edges. But as I learned to balance my weight better, and got faster, it wasn't needed, and too sharp made it harder for me to do turns at speed. So I deliberately don't try to create as long or sharp an edge as I used to. I don't know how typical that is.

I haven't gone as far as switching to a larger ROH, because I've already bought 3/8" ROH tools. (Which I suppose argues against doing your own sharpening, if you think you might change ROH soon. )

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Has anyone experimented to determine how sharpness and the exact edge shape affect the tendency to travel in spins, and the tendency to lose speed of travel in twizzles? Both of which I find very difficult. When I manage to stay level and it feels smooth (which I've only been able to do since my most recent coach figured out what I was doing wrong there), I cannot sense when and how fast I am traveling, which makes it impossible to solve the problem. I honestly don't know how people sense it, and coaches haven't been able to help me do so. Would more or less sharp edges, or edges shaped to a different tilt, help?

Does sharpness or edge shape significantly affect jumps? My most recent coach said I need to increase the stiffness (stabilizing muscle use) of my upper body, and work on balance, alignment and timing, but I wonder whether different edges would magically help.