Sharpening Discussion re: John Wilson Phoenix Blades (2020)

[tstop4me]

How good a job does the H.D.I. tool do of measuring rocker, and how does that work?

The H.D.I. doesn't measure rocker (by which I assume you mean the blade curvature along the longitudinal axis from toe to heel) at all.

ETA:  You're probably thinking of this rocker gauge:  http://www.iceskateology.com/Skateology/Rocker_Radius_Gauge.html

[supersharp]

"Off-topic again: How do you know Ultima Apex Elite or the MK Dance use dovetail (i.e., wider at the bottom) shapes? I used and sharpened my MK Dance blades - and didn't notice the problems that might have caused. I can't find anything else online that says they use dovetail shapes."

I have sharpened multiple pairs of Apex Elite blades, and they appear pretty clearly dovetailed to me. The parallel sides allow a clear datum for a square, and the dovetail has no chrome relief to create an inconsistent angle. A good design, really.  If there are truly advantages to the flared edge, they are available without the loss of sharpening consistency.  I'll add that I'm not disputing that there may be advantages to the flared edge with consistent, level sharpenings, I just haven't seen any real evidence that it makes a significant difference...but I'm in a small, isolated community in the middle of nowhere.

My mistake on the MK Dance—they are narrower at the bottom but not dovetails. Not really the same thing at all.  They appear to want to produce a narrower blade for quickness from edge to edge, but they provide the necessary strength, torsion resistance, and stability by only narrowing the width on the bottom 5 to 6 mm. Also tapered from front to back IIRC. I have a pair sitting in my shop and will do a detailed inspection tomorrow. 

I should probably ban myself from posting after a 2-hr freestyle with a lesson.  At least I have the sense not to go near my sharpening equipment at that point.

[Isk8NYC]

Mod note: split topic into detailed technical sharpening and original product discussions.  Carry on.

[Kaitsu]

Coming back to square check, which I assume to work also Phoenix blades. Checking / judging with the square should not be so difficult.
See videos:
https://www.youtube.com/watch?v=DbrR3hBtm70
https://www.youtube.com/watch?v=m9cakeYd_-E

[supersharp]

I've never seen a machinist square with a point like that, what's the purpose? 

[Query]

In the first of those videos, the skate tech finishes the edge using a cylindrical stone, like that used in the Pro-filer - but without a handle to keep the stone centered.

I've tried that. I am unable to keep the stone centered and aligned well enough to create sharp, let alone even, edges that way. But some people have better fine motor control than me. I have seen it done - and other people who can sculpt a variable ROH hollow pattern (I'm not sure what the benefit is) using a stone with a finer radius stone than the hollows they are creating.

Does anyone know what are the advantages/disadvantages of the Incredible Edger vs the Wissota? The I.E. is a lot more expensive than either the Wissota or the low end Blademasters, so perhaps it does something better.

[Query]

One minor problem with checking edge evenness at different points along the blade by using a square: It assumes there is no twist-warp in the blade. I THINK it is better to use visual line-up of two straight edges on different parts along the blade, and just use the square at one point - though maybe it makes sense to verify that the air gap looks the same on the opposite edge in that place too.

But lining up to straight edges isn't quite right either. It can verify that the edge heights are the same, but the edge shapes would still be slightly different, if there is twist warp. But you can't compensate for everything in a twist-warped blade, unless you actually remove the twist warp.

Maybe JW/HD Sports could sell a kit for hand sharpening Phoenix blades to end-customers whose pro shops can't handle them - except pro-shops wouldn't like that.

Would it really have been so hard to just make sure that all JW/MK blades can easily be sharpened with all the same common types of equipment? I wonder if they shave more than a few grams off the weight by making it just enough harder that some pro shops have trouble. In the long run, that type of trouble might hurt their reputation, especially since they market Phoenix blades to high end customers.

And maybe they should ship each pair of blades with detailed, well illustrated sharpening instructions, in the shipping container to pro shops. The pro shop could keep those instructions, and use them to help train their skate techs. Despite the time pressure, I think a lot of skate techs would do a better job if they just knew how. Anything HD Sports could do to help would be a good thing. Or is that unrealistic?

[supersharp]

One minor problem with checking edge evenness at different points along the blade by using a square: It assumes there is no twist-warp in the blade. I THINK it is better to use visual line-up of two straight edges on different parts along the blade, and just use the square at one point - though maybe it makes sense to verify that the air gap looks the same on the opposite edge in that place too.

But lining up to straight edges isn't quite right either. It can verify that the edge heights are the same, but the edge shapes would still be slightly different, if there is twist warp. But you can't compensate for everything in a twist-warped blade, unless you actually remove the twist warp.

Good point about twist. I try to be really vigilant about twist warp and spend a lot of time checking when mounting new blades (not something I understood at first, but fortunately I became more aware over time). When blades come to me with twist-warp or just a curved mounting, I let the skater/parents know and recommend we fix it so the skater's skills will transfer more easily to the next set of blades.

I've read comments that a little twist or a slight curvature don't matter, but they also aren't doing the skater any favors. It's a bigger problem at low speeds, so probably more of a problem for beginners and some adults.  Hard on coaches, too, because they often need to do long, slow demonstrations to get the idea of a new skill across.  Skating is hard enough even with perfect equipment.

[/quote]

And maybe they should ship each pair of blades with detailed, well illustrated sharpening instructions, in the shipping container to pro shops. The pro shop could keep those instructions, and use them to help train their skate techs. Despite the time pressure, I think a lot of skate techs would do a better job if they just knew how. Anything HD Sports could do to help would be a good thing. Or is that unrealistic?

[/quote]

I would love for this to happen. Not sure why it isn't more of a priority for HD or any of the other manufacturers.  If we can keep the blades in good shape, skaters will like them better, so wouldn't it be good for business?

[Kaitsu]

I've never seen a machinist square with a point like that, what's the purpose?

I am not sure which tool you are using to check edges evenness, but most of the tools measures if edges are 90 degrees angle to the chromed side planes. There are several BAT gauges on the markets which uses either magnets or magnet + screw. One part of the tool lays against the chromed plane and another on top on grinned edges, means they are in 90 degrees angle to each others, if edges are even.

It is true that with the square you cannot detect if blade is twisted. It can detect only if blade is not straight...in certain level. Blade straightness I will check every time when I have new pair of skates on my hands. Too many skate techs just mounts the blades on the boots without confirming how they change the geometry of the blades. Ensuring the blade straightness after the blade mounting should not be too much for asked. Well, I will try to keep on the topic. I agree that using two straight edges in different ends of the blade possibly identifies the wrapping issue. With this method you need to visually line-up if straight edges are parallel to each others. You can also visual line-up if they are in 90 degrees angle compared to chromed surfaces. Longer the straight edges are, basically more accurate they are (if the datum surface is also long enough). Its a matter of opinion which one (square or visual line-up) measures angle more accurate. With the square the measuring length is much shorter, which obviously reduces accuracy even tool manufacturing accuracy would be superb. Its also good to keep in mind that different sides or blades are not necessary parallel and quite many times chromed blades has lots of geometrical deviations already at the factory condition.

As Query mentioned, we cannot compensate everything, even we would like to do so. We cannot example control blades manufacturing process. For this reason I have not used chromed blades for my daughter. It has been my way to ensure that at least some errors are excluded already at the blade manufacturing process.

Still few words about the BAT gauges. As Bill was witnessing us, BAT gauges manufacturing is not necessarily any high-accuracy production. Tool it selves can have remarkable deviation. Even the tool it selves would be OK, especially cheaper blades can have barrel shaped. Magnet which attaches to the chromed surface is pretty short and it can be actually slightly tilted. This is not so easy identify. I did try to explain this issue in my sketch.

There are lots of sharpeners which does not use any gauges and they sharpen hockey skates, figure skates with same setups. I have even seen that local sport goods shop was sharpening figure skates handheld without using skate holder.

Edited:
Ones again I didn't read the question properly and replied totally wrong thing. Idea of the beveled end is that you can enter in to the corners. See updated attachment.
If you are wondering idea of the knife edge design, its made to increase accuracy. Knife edge does not create shadows like a flat design.

[tstop4me]

I've never seen a machinist square with a point like that, what's the purpose?

The blade in the videos has one end beveled.  Common bevels are 45 deg and 30 deg.  Just eyeballing the video, it appears to be 45 deg on one end (pointed end) and 90 deg on the other end.  Some blades are beveled at both ends (45 deg on one end and 30 deg on the other end).  These are common angles used in machine design, and these bevels can be used to check them.

There are all sorts of oddball blades for squares.  See, e.g., https://www.starrett.com/metrology/product-detail/453E

[Bill_S]

There are all sorts of oddball blades for squares. 

Here's an oddball square for you.  It's one that I made in the early 1970s.

I still use it today for small parts. To make it again, I'd need a mill, a lathe, and a surface grinder, plus tooling for those machines.



Of course its lack of measuring gradations means that it can be used only as a try square, but it's good at that.

For use with sharp blades, I'd like to see a square a bit smaller than this one, and with an aluminum body instead of steel. Soft aluminum wouldn't pose nearly the threat to freshly-sharpened edges.

Hmmm...

[Kaitsu]

For use with sharp blades, I'd like to see a square a bit smaller than this one, and with an aluminum body instead of steel. Soft aluminum wouldn't pose nearly the threat to freshly-sharpened edges.
Hmmm...

I have used just and only precision square and never noted any issues by damaging freshly-sharpened edges. Higher risk I have seen in the deburring. It has happened several times that I have failed in the deburring and therefore have been forced to make few extra passes. H.D.I gauge...or its dial gauge tip harms more easily edges.

[supersharp]

The blade in the videos has one end beveled.  Common bevels are 45 deg and 30 deg.  Just eyeballing the video, it appears to be 45 deg on one end (pointed end) and 90 deg on the other end.  Some blades are beveled at both ends (45 deg on one end and 30 deg on the other end).  These are common angles used in machine design, and these bevels can be used to check them.

There are all sorts of oddball blades for squares.  See, e.g., https://www.starrett.com/metrology/product-detail/453E

Thanks everyone, for the clarifications, pretty obvious about the bevel being for corners. 

Thanks for the drawing, Kaitsu, very nice.

You can tell I'm an engineer rather than a machinist...with most of my work being on things that are on a much larger scale, like pipelines, roads, and buildings. Not a lot of call for this scale of precision, particularly in the hazardous materials niche where I spend most of my time these days.  All of my fine precision at work these days is focused on calibration of equipment for measurements of contaminants at low levels, or on the wording of specifications. Not nearly as fun as fine-tuning equipment.

I have the version of that Starrett square in the photo in tstop4me's link, but none of the other blades for it, plus the original smaller precision square that came with the old IE machine.  I have never used a BAT gauge or any magnetic tools on skates, they always seemed too clunky to really be accurate.  I know some people just eyeball the blade and say it's square, but I don't think my eye is trained to that accuracy.  As far as edge damage goes, I check for level before I hone and polish the edges, so any minute damage should be blended into smoothness once I'm done...or at least it seems that way.

The BAT guage could be useful for checking for twist, maybe?  I think I prefer flat bars so I don't have to worry if the magnets are losing precision.  On blades that I didn't mount, I often notice twist and bend when I clamp the blades for final polishing.  I use the holder from the original IE since it is designed for clamping onto skates, held on its side so the boot is underneath and I can work on the radius.  As the sides clamp shut, you can see the blade being forced into straightness.  It is easier to see curvature than twist, because you see the gap at the center and ends on each side, but twist is also revealed when the final clamping makes the boot move, particularly when you see the heel move but not the front of the boot. 

It is great to have the opportunity to learn from the rest of you on this, I have been in a vacuum up here trying to figure this out on my own. 

[Bill_S]

Sounds like you're a Civil Engineer. I was a Mechanical Engineer.

Sometime I'll tell you about the annual softball game between the C.E. and M.E. students at my alma mater in the 70s. Not to give the story completely away, but white paint and a grapefruit were involved.

[supersharp]

Sounds like you're a Civil Engineer. I was a Mechanical Engineer.

Sometime I'll tell you about the annual softball game between the C.E. and M.E. students at my alma mater in the 70s. Not to give the story completely away, but white paint and a grapefruit were involved.

Hahaha!  Sounds very entertaining. Yes, I'm a Civil Engineer. 

[Query]

I have used just and only precision square and never noted any issues by damaging freshly-sharpened edges. Higher risk I have seen in the deburring. It has happened several times that I have failed in the deburring and therefore have been forced to make few extra passes. H.D.I gauge...or its dial gauge tip harms more easily edges.

I'm not an engineer, and tend to use cheap tools. I once went into dollar stores, found a cheap plastic square that was too big to fit against the side of a skate, probably part of a drawing set (or maybe the square corner was on the inside of something), and cut it down to size. I had to search a lot because most plastic squares are rounded at the corner. I verified the angle was right by testing the blade on both sides. But the resulting tool was very small, and I lost it. Nonetheless it was very light, and unlikely to damage the edge. I may do it again some day.

Plastics typically have a larger coefficient of thermal expansion than metals. Perhaps that means shapes change more with temperature?

With Pro-Filer, I now take a few strokes in one direction, reverse the skate or Pro-Filer, and take a few more and repeat. That evens things out, and there is no uneven edge problem. Also, it is a short enough tool to follow minor blade warps, so they are no problem. Of course, if the gap between the blade and the tool was significant, there would be too much position shift, and I wouldn't get good sharp edges - one of the reasons (aside from reducing scratches) for first putting tape on both sides of narrow blades, to make the gap snug. It also would create sharp edges if the tool had an off-center gap, or if a blade had an abrupt bend, like I am told hockey players sometimes get when blades collide at high speed.

I could do the same even better with the old (about 1930-1950) Berghman sharpeners, if I decide to switch to .5" ROH. The adjustable gap size (I do have one old-style Pro-Filer with a slightly adjustable gap too), and the ease of seeing what you are doing are huge improvements, as long as you use a better quality modern cylindrical stone than crumbly coarse ones that they came with.

It is true that some very good, experienced skate techs manage to produce very good edges without using measuring tools most of the time. I think they just get a feel for what they are doing after a long period of practice. But a lot of the people who use no measuring tools are just trying to work in a hurry, or don't know how to do better.

But I now believe the "magic of measurement" is very useful for less experienced learners who want to learn to do the best they can. It took me a long time to figure out that measurement makes sense for learners. I had minimal instructions (a few minutes or less from the guy who sold me my Pro-filer, a display model that had no written instructions), had to mostly teach myself how to sharpen, and made a lot of early mistakes. E.g., I used to slow down my strokes too much at the ends. The result was that I gradually flattened the rocker on a pair of MK Dance blades, and I didn't even know about the sweet spot (rocker radius transition point). By that time I had learned to take off extremely little metal per sharpening, which meant that the blades lasted me for many, many years and many thousands of hours on the ice - so that systematic change I created with each sharpening had lots of time to build up. In the end, I took the blades to an expert skate tech who could reshape the rocker profile back to the original shape rapidly with a powered sharpening tool.

I also used another expert skate tech when I did my experiment trying to reshape the rocker profile of Jackson Matrix Dance blades to that of MK Dance, using a bench grinder, which created no ROH and probably uneven edges. If I had tried to create the rocker or ROH using a Pro-Filer, it would likely have worn out the diamond dust stone.

I don't think we should be bothered by sometimes going to the real experts who have the real professional grade tools. If we can do most of our own sharpenings, and produce sharper edges (if that is what we want, and I often do, especially if I am to skate on rough ice) and less rocker change (or only the desired changes) than most pros, that is still an achievement.

But I can see how those of you who have invested in purpose-built powered sharpening machines, which don't come cheap, would want to be able to do everything yourself.

This is going to be a very strange idea, but are there metal-cutting router bits that can grind the profile or impose an initial ROH (prior to refinements with better tools) on the relatively hard (Rockwell C of about 60) metal in high end skate blades? I don't have a router (though I might be able to buy one used, or use a router-adaptor that is powered by a hand-held drill) and would have to make a custom (very narrow) router table, but I wonder if that could be done. I picture guiding the router along a desired profile shape with a drafting spline, bent to the desired profile shape, which would first be fit to a printed shape made using software and a printer.

Or would any router bit be completely worn out on such hard metal?

[Bill_S]

This is going to be a very strange idea, but are there metal-cutting router bits that can grind the profile or impose an initial ROH (prior to refinements with better tools) on the relatively hard (Rockwell C of about 60) metal in high end skate blades? I don't have a router (though I might be able to buy one used, or use a router-adaptor that is powered by a hand-held drill) and would have to make a custom (very narrow) router table, but I wonder if that could be done. I picture guiding the router along a desired profile shape with a drafting spline, bent to the desired profile shape, which would first be fit to a printed shape made using software and a printer.

Or would any router bit be completely worn out on such hard metal?

Don't try that! Most router bits have carbide cutters, and very brittle. You'll frag a router bit and hurt yourself!

[Query]

Don't try that! Most router bits have carbide cutters, and very brittle. You'll frag a router bit and hurt yourself!

Thanks!