what can we use to test blades that need to be sharpened?

[marc]

I've been wondering for a long time how you can test a skate that needs sharpening.
for the moment I'm using the fingernail technique but I don't really like it (and I wouldn't have enough nails!).
Before having my own machine, I didn't ask myself all these questions, it was roughly every 40 hours, but now that I have the machine I do it for my daughter every 20/25 hours).
but I would like to have a serious technique...
And I would love to have your ideas or advice.
Hello to you enthusiasts of the south of France!

[AlbaNY]

My main coach used the fingernail method and assured me I was good to go still with 80 hours on my first ever sharpening.  I also have never found it to make any indication compared to how I felt while skating.  Perhaps my nails are soft (they are,) but it just never seemed like a useful test.

I routinely have gone that long between sharpenings, but I do enjoy the secure feel if done by a bit over 40 hours.  Even if I had the option for 20 hours I'd be reluctant in order to save blade longevity since I guess I can get away with the handling.  My main coach hasn't had his blades sharpened in over two years now but has great edges.  Dullness forces you to use pressure.
Without a trusted tech here I went from June to February without any sharpenings (  )
It's a very personal experience thing as far as sensitivity to sharpness and how it feels.

As to the question... I find a careful look will tell.  You just see the obvious nicks and general lack of sharpness in the edges or in how light gleams on them.  Obviously I am a not scientific minded person but go by senses.  I bet Kaitsu and BillS will have more precise answers. 

[Bill_S]

I used nothing scientific when I skated. I always went by feel. One thing that I noticed was that the more advanced my skills became over the 23 years that I skated, the more tolerant I became of edges becoming dull.

I would venture a guess that most skaters, except for beginning skaters, can tell when their edges start to slip. That's when it's time for a sharpening. For the inexperienced, they won't have deep edges to worry about and an approximate number like 40 hours will suffice.

Unless there is impact damage, 20 hours seems too short and could impact blade life. A few minor (and inevitable) nicks won't hurt anything, so don't chase perfect edge condition at the expense of blade life.

[tstop4me]

I've also tried several proxy methods.  To test for a sharp edge, I've used the fingernail test.  Even more sensitive for me is the fingertip test. If I run my fingertip across (not along) a really sharp edge, I can feel it and also see traces of shaved skin fragments left behind.  This works only if my fingers are thoroughly dry.

I also have a HDI (Hollow Depth Indicator) gauge, in which I swapped out the stock dial indicator for a higher-resolution digital indicator.  I thought maybe if I tracked the decrease in depth of hollow as the edges wore down, I would get a proxy for when sharpening was due.

None of these methods were successful.  Mainly because I touch up my edges with burnishing rods.  So I can maintain a sharp edge, but the edge angles vary and the degree of bite varies.

So ultimately I know it's time for a sharpening, even after repeated rounds of burnishing, by actual performance (starting to slip).  For me, primarily reduced control on back cross-overs and entrances to one-foot spins are the early indicators.  I do keep a log of hours of skating after a fresh sharpening.  But it's only a rough guide, because it depends on what moves I'm concentrating on:  different portions of edges get worn down more quickly than others; and different portions of edges are more critical than others.

[Query]

FWIIW, many skate techs say once every 40 hours on the ice is typical for figure skaters.

But there is a lot of variation.

Not just by skater, but by the type of ice you skate on. Rough ice, and dirty outdoor ice wear out blade edges a lot faster.

I currently sharpen more often, maybe every 8-15 hours, because I love sharp edges, but I use hand tools (mostly Pro-Filer) that remove a lot less metal than powered machine tools, I think because they reshape the steel somewhat more than remove it - the blades still last me for years, and probably well over 100 sharpenings. But about 30 sharpenings seems roughly right for sharpening using powered machines. Maybe worse if you are still having a bit of trouble centering the blade position on the wheel when sharpening.

Is your daughter old and safety oriented enough to learn to sharpen her own skates? It might encourage her to take good care of her blades. (Or not. ) I've watched a lot of kids run off the ice onto the rubber mats surrounding the rink, and out to the lobby or bathroom, with no concern for their blades, secure in the knowledge that their parents will get them sharpened and replaced as needed. Of course, some adults aren't much more careful.

I've also seen some who don't dry their blades after use, leave their blades in blade guards between uses, or store their skate in a closed bag, box or trunk. All of those increase corrosion and shorten edge and blade life. Hopefully your tool experience means you have explained to your daughter what she should do to preserve her blades as much as she can.

[R45]

As mentioned already, the tolerance towards dullness of the edges is a personal preference.
Many skaters are under the impression that edges are not allowed to slip. But controlled sliding is part of skating.
Dull edges have a bit the same effect as a more shallow hollow: you have no choice but to learn how to control your edges more effectively.
I sharpen my skates once a year, mainly to get the nicks out.

[marc]

salut l'equipe des affuteurs :
je reviens ici car j'ai pas trouvé encore une bonne methode pour bien verifier si les patins que j'affute  sont biens affutés ou non?
je fais ,comme dit dans mon premier message, le test des ongles, mais je fais de plus en plus d'affutage de patins et j'ai de moins en moins d'ongle ( à mon pousse gauche, pour tout vous dire, car c'est celui qui me va le mieux!!!)
cela peut m'arriver de   passer plusieurs fois ( 2 à 3 fois)  mon ongle ...
j'ai essayé un baton de bois mais j'ai plus confiance à mon ongle!!!
j'ai vraiment besoin d'une astuce serieuse autre que cela!!

Hey sharpening team!
I'm back because I still haven't found a good way to properly check if the skates I'm sharpening are actually sharp or not.

As I mentioned in my first message, I do the fingernail test, but I'm sharpening more and more skates and I have less and less nail (on my left thumb, to be honest, because it's the one that works best for me!). I sometimes have to run my fingernail over the surface several times (2 or 3 times)... I tried a wooden stick, but I don't trust my fingernail anymore!
I really need a reliable tip other than that!

[Query]

I too run my finger very lightly across (not along) the edge.

Good coaches can tell if a figure skater is slipping across the edge. You could learn to - but maybe you would need to be a skater yourself to understand what to look and listen for. BTW, sometimes the slippage only occurs during jumps and spins.

Hockey skaters deliberately slip a lot of the time. If they are experienced, they (and hopefully their coaches) know when they are slipping too much, just as experienced figure skaters and coaches do. And hockey goalies often want part of their edges to be very dull, to slide side-to-side.

Unless you really know what you are doing, maybe it is best to let the speed skating community handle their own blades, because they are very, very picky.

Some poor edges occur because an edge has been knocked to one side, even if it is still sharp. The edge does not point directly downwards. You can feel that with your finger. Sharpening such an edge wastes metal.

tstop4me has mentioned straighting edges with a "steel" (I don't know the French language equivalent). I use a flat sharpening stone - but my stone has about 5000 grit size, which is very fine.

Nicks in the edge on the blade, caused by collisions with other blades, can often cause slippage, even if the rest of the blade is sharp. Fixing that requires taking off a fair amount of metal, so consult with the skater or coach first. Though it is pretty routine for hockey skaters.

Also, if a person constantly walks on and off ice - at some facilities ring guards do that, and so do some coaches - being super-sharp is bad, because extra sharp edges get knocked down more easily.

The required sharpness depends somewhat on ice temperature and conditions.

So - no hard and fast rules. People learn from experience.

[Kaitsu]

As others have already concluded, the skater should be the best person to judge whether the skates have enough bite or if they should be sharpened. However, parents often bring skates to me to check whether they need sharpening or if the skater can continue using them for a few more weeks.

In 90% of cases, I can answer without even seeing the skates: if they have been on the ice more than 20 times, it is better to sharpen them now that you have already brought them to me. If they are not in very bad condition, we do not need to remove much material, which benefits the skater. The less you need to grind, the smaller the change for the skater as well.

As a rough estimate, 2–3 weeks of skating typically requires about 5 grinding passes. After 2–3 months of skating, 15–20 passes may be needed.

In 99% of cases, skates do not become dull from the ice itself. Instead, they hit each other or come into contact with something harder than ice, which can damage the edges even during the first skating session. Walking without skate guards off the ice is a typical root cause. These damages are usually local, but often long enough to disturb the bite. To detect all these local spots, you should use all your finger nails to "scan" the entire blade.

Based on this experience, I primarily use visual inspection https://youtu.be/t2lsaShlpIA.
A sharp edge does not reflect light like a mirror, but when it is damaged, it starts to reflect light. A dull edge will shine under bright light. I sharpen the skates until the shiny areas disappear. Of course, you need to use common sense regarding how small or short imperfections can reasonably be left.

When I am satisfied with the edges and confident that the sharpness is consistent along the entire blade, I perform the fingertip test, just like tstop4me.

[Qsior]

When I am satisfied with the edges and confident that the sharpness is consistent along the entire blade, I perform the fingertip test, just like tstop4me.

Oh Yes , It's so important to learn how to test with your fingertip because your fingernail won't last long,
I was quickly tempted to stop using mine on my thumb .

Kaitsu great video as usual

[Query]

BTW I found that my fingernail is too soft - the blade doesn't need to be very sharp to shave it.

I don't know if all fingernails have the same hardness.

[tstop4me]

Oh Yes , It's so important to learn how to test with your fingertip because your fingernail won't last long,
I was quickly tempted to stop using mine on my thumb .

That's a rather odd response.  I use my fingertips instead of my fingernails because I find that my fingertips are more sensitive detectors.  But if you're concerned with wear-and-tear, fingernails are more robust than skin.  And you do have ten fingernails, and fingernails do grow back.

[tstop4me]

I thought this was an intriguing challenge.  Here's one solution I've come up with that works fairly well.  It mimics the fingertip test, but spares the skin off your fingertips.

NB:  Make sure edges are clean (in particular, free of lubricants) and dry before testing.

As a test sample, use a paper strip ~1 cm wide X ~12 cm long.  The paper should be of intermediate grade, such as used in a notepad or for a printer.  Not too low grade, with loose fibers.  But not too hard and smooth either.  Play around with different types of paper.  As shown in the photo, grasp the left end of the strip between the thumb and forefinger of your left hand.  Similarly, grasp the right end of the strip between the thumb and forefinger of your right hand.  The skate is secured with the blade facing up. You can sit and clamp it between your thighs, or use a custom holder.

Pull the strip taut against a single edge.  Now pull the strip back and forth (left to right and right to left) for several one-way strokes.  You have ~8 cm of travel over the strip per one-way stroke. Test the inside and outside edges separately. 

With a sharp edge, you will feel resistance as you pull the strip across the edge.  At the end of several one-way strokes (I use four one-way strokes), you will find noticeable paper fibers deposited in the hollow along the edge.  Clean off the paper fibers before switching between inside and outside edges.  With a dull edge, the paper will slide over the edge with little resistance, and there will be no or few fibers deposited.  You will need to develop a feel for how taut to pull the strip, how to angle the strip against the edge, how hard to press the strip against the edge, and how quickly to pull the strip.  But the fingertip test requires similar personal touches too.

[marc]

tstop4me
je trouve ton idée bonne et interessante et je cherche quelque chose comme cela.
je n'arrive qu'avec mes ongles et je n'arrive pas à bien sentir avec le bout des doigts.
j'avais pensé au papier.
mais j'avais pensé aussi avec une chute de bois et il me faudra l'essayer bientôt , car j'apprends à ma fille (15 ans) à affuter et je voudrais pas qu'elle use ses jolis ongles!

[tstop4me]

mais j'avais pensé aussi avec une chute de bois et il me faudra l'essayer bientôt , car j'apprends à ma fille (15 ans) à affuter et je voudrais pas qu'elle use ses jolis ongles!

Yes, your number one priority is to be a good dad and protect your daughter's fingernails.    I once showed a teenage girl how to lace her skates better.  But she got upset when she broke two fingernails.  She got even more upset when I told her that her long fingernails were interfering with proper lacing and that she should cut them.