Does "steeling" a skate blade straighten it?

[Query]

Someone on this board has played with using a kitchen "steel" to re-straighten a bent skate edge.

This link suggests that steeling edges doesn't always straighten them - it usually rounds them off instead. However, that was tested on knives, not on skate blades.

Unfortunately, I don't have as good a microscope as that person (he uses an electron microscope), and cannot verify what he says for skate blades.

I wish I did. When I sharpen and otherwise modify my own skate blade edges, to some extent I have to guess what happens.

[tstop4me]

Someone on this board has played with using a kitchen "steel" to re-straighten a bent skate edge.

This link suggests that steeling edges doesn't always straighten them - it usually rounds them off instead. However, that was tested on knives, not on skate blades.

Unfortunately, I don't have as good a microscope as that person (he uses an electron microscope), and cannot verify what he says for skate blades.

I wish I did. When I sharpen and otherwise modify my own skate blade edges, to some extent I have to guess what happens.

<<Emphasis added>> And by implication you conclude that steeling an edge actually degrades the quality of the edge (i.e., makes it more dull) rather than improves the quality of the edge (i.e., makes it more sharp).  But Science of Sharp (SOS) does not conclude that steeling an edge usually rounds it off.  In particular, refer to the results obtained with a smooth (polished) butcher's steel.  The scanning electron microscopy (SEM) analysis shows that steeling improves the quality of the edge by increasing its keenness [SOS makes a distinction between "sharpness" and "keenness"]; the conclusion is that steeling increases the keenness of the edge by forming a new micro-bevel via removal of a micro amount of material (on the order of microns thick), rather than by reforming the edge via plastic deformation without any material removal.  But the result is still a better (not worse) edge.

What happens on the micro level depends on a lot of variables, and the SOS results should not be generalized.

There's an old adage, "The proof of the pudding is in the eating."   Similarly, the proof of the steeling is in the skating.

[Query]

I read the article too fast, and came to the wrong conclusions.

However, he still questions the extent to which steeling straightens edges... He mostly doesn't seem to think a "major deflection" as he calls it occurs.

When you steel an ice skating blade, how do you do it in detail?

I assume you slide it along the side(s) of the blade to reshape the outside of the edge, but tilted inwards a bit to get that micro-bevel and avoid scratching the sides.

But to get the inside of each edge (i.e., the side of each edge that is closest to the hollow), do you slide the steel next to that as well, presumably being careful not to touch the opposite edge?

If steeling removes less steel than conventional sharpening, yet works just as well, and creates just as durable an edge (Is it??), it would be better, because it would extend the life of the blade - and maybe one should NEVER do a conventional sharpening, but only steel it.

However, if you are also steeling the inside of each edge, that requires that there still be a hollow, which means you would still sometimes need a conventional sharpening.

And is there an actual reason one needs a hollow - or would an ultra-keen micro-bevel created by steeling be good enough? (I have a totally unconfirmed theory, that the hollow provides a place for the liquid water under the edges to move to, so the edges don't hydroplane across that water, which would cause skidding. If I'm right, the hollow is useful, at least for figure and hockey, where skidding would do more harm than for speed skating.)

Another interesting question - I have been using a flat stone instead of a steel. I assumed that it deflected the edge vertical again, and polished it smooth again. But is it really mostly doing the same thing as this article suggests a steel does on knives - i.e., creating a micro-bevel? And is there a reason to prefer one tool over the other?

Yes, you are right, the proof of any skate sharpening technique lies in how it interacts with the ice, not in how it looks. But also, on how much depth of steel you remove by sharpening, and therefore on how long the blade can last.

And, of course, "works just as well" isn't just determined by how well it presses against the ice, and constrains the blade to glide mostly along the length rather than skidding sideways - it is also determined by how well the blade glides, without creating too much friction. Scratches MIGHT slow it down significantly.

It's also hard to test edges objectively on the ice, without letting one's opinions about what SHOULD happen affect the results. I admit I have a couple problems evaluating edges. I am not consistent at spinning and jumping - which means I cannot judge consistently how a given sharpening technique affects those things. To evaluate edges consistently, one must perform consistently, else one has an uncontrolled variable.

[tstop4me]

(1)  As I wrote previously, what happens on the micro level depends on a lot of variables, and the SOS results should not be generalized.  I've also seen SEM analyses that concluded that steeling does reform (straighten) an edge.  But the results are dependent on the specific blade, specific damage imparted to the edge, specific steel, and specific steeling process.  Also note that the blades used in the SOS study were Olfa blades.  Olfa makes a variety of utility, trade, and craft blades; the high-end ones are wickedly sharp.  Olfa blades are not representative of more common knives, such as kitchen knives, pocket knives, sports knives, or hunting knives.

(2)  Although detailed studies are useful in selecting and improving tools and processes, ultimately what we are concerned with are the following two key high-level issues:

(a) Does steeling improve the function of the blade?

(b) Does steeling remove substantially less material than abrasive grinding? 

(3) Note that steeling is not intended to replace abrasive grinding, but to (i) augment abrasive grinding in creating a superior edge after initial sharpening via abrasive grinding and (ii) to extend the service life of the edge before resharpening via abrasive grinding is needed.  As an edge becomes damaged through use, steeling (in some, not all, instances) can repair the damage (at least in part).  Here I'm intentionally using the high-level expression "repair the damage" to avoid discussion of what happens on the micro level. 

(4) From long-term practical experience in sharpening knives, I know that steeling is effective if performed routinely before a knife becomes noticeably dull:  if the edge is too dull, steeling won't rescue it.  Eventually, though, steeling loses its effectiveness; and a fresh sharpening via abrasive grinding is required. 

(5) Also from long-term practical experience with sharpening knives, I know that steeling removes substantially less material than abrasive grinding.  Whether a process removes no material or a few microns has no practical impact on the service life of the blade.

(6) With respect to skate blades [ETA:  standard parallel geometry, to simplify the discussion], a hollow (or channel) is needed if (i) you want to have a blade with two edges and (ii) you want the included angle in each edge to be less than 90 deg.  Speed skates have no hollow (or channel) because the included angle in each edge is 90 deg.  A hollow is commonly used for skate blades because the included angle can be readily varied by dressing the grinding wheel to a specified radius of hollow.  In this instance, the included angle and the depth of hollow are both initially set by the radius of hollow (in the absence of additional honing).  Other edge configurations exist, however. E.g., in the flat-bottom-V edge configuration used for hockey skates, the included angle can be varied independently of the width and the depth of the channel.

(7) For steeling skates, I've played with several different steels, and my technique has evolved over the past several years.  You can use either a steel that is completely smooth or the smooth tip of a steel that has ridges cut into it (most steels have ridges cut into them, but many have a smooth tip ~3/4" long).  I grasp the tip of the steel between my thumb and first finger and wrap my other three fingers around the shaft of the steel; I also use my thumb and first finger as guides along the sides of the blade.  To avoid damage to the toepick, I always start the stroke just behind the toepick and pull the steel towards the heel.  When I first started, I steeled only the edges outside the hollow (which still worked well).  As I became more adept, I steeled the edges both inside and outside the hollow (which worked even better); for each edge, typically three swipes on the inside, followed by three swipes on the outside.

Typical kitchen or butcher's steels have a shaft 9" or longer plus a handle (and some handles are heavy).  These can be unwieldy for steeling skate blades, unless you take special steps.  What I do is place the skate boot on its side, resting on a floor or tabletop.  I hold the boot with one hand.  With the other hand, I grasp the tip of the steel between my thumb and first finger, which also press against the sides of the blade.  I let the handle of the steel drag along the floor or tabletop, so I don't need to deal with supporting unbalanced weight. 

At one time I did consider making a tool using the shank end of a drill bit (not sure whether the shanks these days are hardened), but I then came across this short Victorinox steel [5" nominal length shaft with a lightweight plastic handle; it has ridges over most of the shaft, but a smooth tip] that makes handling easier:

https://www.amazon.com/Victorinox-Honing-5-Inch-Regular-Plastic/dp/B000931E4E/ref=sr_1_7?s=home-garden&ie=UTF8&qid=1535716986&sr=1-7&keywords=victorinox+smooth+steel

( 8 )  I don't do any jumps; I concentrate on edge work and spins.  With a Coronation Ace blade and no steeling, I typically needed a sharpening every ~40 hrs of ice time.  With a steeling every ~7.5 hrs, I typically needed a sharpening every ~120 hrs.  My current blade is a Paramount Freestyle 12" in 440C stainless steel.  It was sharpened when first purchased.  With a steeling every ~7.5 hrs, I have now accumulated ~270 hrs without needing a second sharpening (I have no comparison with sharpening intervals without steeling).  These are isolated data points; I make no claims that they are typical.

(9)  Sharpening steels are generally magnetized, either intentionally or as a result of the manufacturing process.  Particles removed from the blade during steeling stick to the steel.  If you wipe the steel with a white paper towel, you can examine any macro particles removed.  Any amount removed is substantially less than the swarf resulting from abrasive grinding.  With my current Paramount blades, the change in the depth of hollow (initial depth of hollow minus current depth of hollow) is only ~0.0005" (which is about the minimum change I can measure with my instrument).  This is based on measuring the depth of hollow at 10 different spots along the blade.  The initial measurements were done after the first sharpening and steeling.  The current measurements were done after ~270 hrs of ice time and an additional 35 steelings.  This is one isolated data point; I make no claim that it is typical.

[Bill_S]

If you even get to an experimental stage, you might include a steel available from Lee Valley that has a very fine diamond abrasive embedded in its surface...

http://www.leevalley.com/us/wood/page.aspx?p=32993&cat=1,43079&ap=1

I use one in the kitchen and it maintains knife edges exceptionally well. It will straighten a curled edge, plus remove a slight amount of material to maintain an edge.

BTW, I read once where abundant and naturally occurring silicates (abrasives) are part of the reason that knife steels work so well. The very fine diamond surface mentioned above take it a step further.

[Query]

Thanks! Lots of interesting info and a good lesson on technique!

I've been using the flat stone every other time or so, at most 2 / 3 times. It sounds like the steel does a lot better at extending lifetime. OK, I'm convinced. And it's something else to play with.

(6) With respect to skate blades [ETA: standard parallel geometry, to simplify the discussion], a hollow (or channel) is needed if (i) you want to have a blade with two edges and (ii) you want the included angle in each edge to be less than 90 deg.

Yes, but do you actually need the included angle ("edge angle") to be less than 90 degrees?

Maybe it is just one way of creating sharper edges, that could be created by steeling, or by creating foil edges. What is more, since you are steeling on both sides of each edge, you may be creating a micro-bevel with a smaller included angle anyway.

E.g., in the flat-bottom-V edge configuration used for hockey skates, the included angle can be varied independently of the width and the depth of the channel.

I assume you know most hockey skaters don't use flat-bottom-V, AFAICT.

As best I understand it, a flat-bottom-V is sort of a faster machine-ground technique of creating a foil edge. But none of the pro shops I know have the equipment to produce flat-bottom-Vs.

I confess I never sharpen or steel kitchen knives. In fact, I just bought a ceramic paring knife ($5 at a so-called "dollar store") that isn't supposed to require sharpening. I have sharpened pocket knives, and an old dive knife used for kayak safety (water creates corrosion). Maybe I should steel them too?

Can you steel drill bits or saw blades?

[tstop4me]

Yes, but do you actually need the included angle ("edge angle") to be less than 90 degrees?

Maybe it is just one way of creating sharper edges, that could be created by steeling, or by creating foil edges. What is more, since you are steeling on both sides of each edge, you may be creating a micro-bevel with a smaller included angle anyway.

Well, as far as I know, only speed skaters use an included angle of 90 deg.  With specific reference to skaters on this forum, here was the recent poll I took of ROH:  http://skatingforums.com/index.php?topic=8072.0   .

But just to back up a bit, you seem hung up on micro-bevels and foil edges.  You can't focus on one aspect of an edge; you need to consider the totality of an edge [which is one reason SOS makes a distinction between "sharpness" and "keenness"].  Going back to a simpler example of a kitchen knife, you typically (not always) grind an edge with a first included angle, then grind a bevel with a second included angle (with the second included angle > the first included angle).  Some manufacturers grind a second bevel at an even greater included angle.  The angles depend on the function of the knife, the composition of the steel, and the preference of the manufacturer, among other factors; but less than 90 deg for sure.  Then you finish the edge with a steel.  It is the totality of the edge, not just the final microns at the apex, that determine the functionality of the edge.  If you sharpen a kitchen knife with a 90 deg included angle on the edge, and steel the edge to a high degree of keenness, you wouldn't have a functional kitchen knife (for most uses; perhaps for cleaving bones). 

The same holds true for figure skate blades.  I do know a couple of advanced freestylists who use shallow hollows (large ROH); and Eclipse suggests a 5/8" ROH for some of their freestyle blades.  But I haven't come across any reference to figure skates with no hollow at all (infinite ROH).  Certainly sharpening would be a lot easier if you could.

I assume you know most hockey skaters don't use flat-bottom-V, AFAICT.

As best I understand it, a flat-bottom-V is sort of a faster machine-ground technique of creating a foil edge. But none of the pro shops I know have the equipment to produce flat-bottom-Vs.

Yes, I know most hockey skaters use a standard hollow, not a flat-bottom-V.  Just to clarify:  flat-bottom-V was introduced for hockey skaters, and has been adopted by some hockey skaters.  I don't know the % of hockey players who use it.  But as far as I know, it's not been applied to figure skates.  As I mentioned above, there are some theoretical advantages (e.g., ability to vary the included angle and channel depth independently).   The question is whether the practical gain in performance outweighs the added complexity in sharpening. 

I confess I never sharpen or steel kitchen knives. In fact, I just bought a ceramic paring knife ($5 at a so-called "dollar store") that isn't supposed to require sharpening. I have sharpened pocket knives, and an old dive knife used for kayak safety (water creates corrosion). Maybe I should steel them too?

I steel all my knives:  kitchen, pocket, and hunting (I don't hunt; I use a hunting knife as a general purpose utility knife).

Can you steel drill bits or saw blades?

Not practical.  The hardness of the steel needs to be greater than the hardness of the edge.  High-grade drill bits are typically made from high-speed steel, with a Rockwell hardness of Rc ~65 or more (see, e.g., https://www.irwin.com/support-services/ask-irwin/4); that exceeds the hardness of many kitchen steels.  You would need something harder [e.g., tungsten carbide or (a favorite of knife fanatics) polished borosilicate glass].  But depending on the specific drill bit, the edge might be more prone to chipping, rather than to repair, via steeling. Saw blades vary more in hardness, but the good stuff generally have hardened teeth.  The drill bits and saw blades you get at dollar stores are likely softer, but then they're so cheap, why bother?

Then there's the practicality of trying to steel the complex edges of a drill bit and saw; especially, consider all the individual teeth (typically, not always, set in a kerf) in a saw blade.  You would need a special tool, not a standard kitchen or butcher's steel ... and that's assuming you have the time and patience.

[Query]

BTW, I don't know anyone who uses flat (no hollow) grinds, but for some reason the USFSA and ISU specifically allow them.

See rules 6035, 7035, 8023 and 9025 of

  http://usfsa.org/content/2018-19%20Rulebook.pdf

Figure skating blades used during competitions and tests (or hockey skate blades used during moves in the field tests or moves in the field events at competitions) must be sharpened to produce a flat to concave cross section without change to the width of the blade as measured between the two edges. However, a slight tapering or narrowing of the cross section of the blade is permitted.

and rule 500 of

  https://isu.org/isu-statutes-constitution-regulations-technical/special-regulations-and-technical-rules/17927-single-pair-and-ice-dance-2018/file

Definition of the skate blade
Figure Skating blades used during competitions must be sharpened to produce a flat to concave cross section without change to the width of the blade as measured between the two edges. However, a slight tapering or narrowing of the cross section of the blade is permitted.

I have known figure skaters who NEVER sharpen their blades, and end up with a slightly convex bottom shape after a few years. If I did that, I would skid all over the place. (I'm told some speed skaters do sometimes skid a bit.)

This skate tech mentions flat grinds, though most of what he says about them is negative, and he doesn't advocate them:

  http://www.fredsskatesharpening.com/qa_blades.html

He does advocate figure skaters use as flat a cross-section as they can manage.

Some of the school figures people come close. I wonder if any of them do grind them flat, to extend the glide.

Because I'm not as fast as the better skaters, I keep meaning to test a somewhat flatter hollow - say 3/4". To save steel, I wouldn't grind the whole hollow, but just the outer few thousandths of an inch. Not a perfect test, but it might tell me if I can get away with them. Perhaps I would need a foil edge or very keen edge to prevent skids, so perhaps I would need to resharpen (or steel?) more often.