How to get good surface finish to blades and how they look?

[Query]

I did indeed assume the surface finish was on the sides of the blade. Oops.

BTW I've known some very good skate techs who sometimes did use a second (fine grain) wheel, after doing a rough cut with a coarse grain wheel.

The point is: the real edge is created by the fine wheel. The coarse wheel is just used to make major shape changes - e.g., if the blade hasn't been sharpened in a long time, or it is desired to alter the rocker profile.

[Kaitsu]

I probably have change to test Dinolite 5 Megapixel USB microscope at January (2022). I will post test pictures if I get that change.

Delivery of microscope took a bit longer than I thought, but here are now the very first test pictures taken with Dino-Lite AM7915MZT and using Extended Dynamic Range (EDR). Used stand was RK-10.
https://www.dino-lite.com/products_detail.php?index_id=130
https://www.dino-lite.com/products_detail.php?index_m1_id=4&index_m2_id=6&index_id=18

Pictures are taken from the blade which I have used in 20 pass test.

[Bill_S]

That does a nice job. It looks like a big step to standardize your photos for sharpening comparisons.

[Query]

Pictures look pretty sharp, for the picture size - which is 150x112 pixels.

As a curiosity, can you increase the resolution, and create a higher JPEG quality, or an uncompressed original, or are those fixed?

[Bill_S]

Query - click on the photos to see an enlarged version. They are way above 150x112 pixels when you click on them.

[Query]

Nice optics! Based on the bottom edge on the bottom photo, the resolution is fairly close to diffraction limits - unless the ringing effect is produced by a digital sharpening algorithm.

Regardless, I bet this is much better than you need to see sharpening defects that significantly affect skating.

I'm jealous.

[supersharp]

Nice photos!  This will be such a good tool for comparison. I want one!

Did you do any edge honing or wiping with a towel before these photos?  I'm curious about what the burrs look like. I can usually see some with no magnification, but have never seen a good view of them with a microscope.

Now I'm trying to come up with justification for this being a defensible work expense, haha.

[supersharp]

I also want to add my compliments for such a beautiful intersection of cross-grinding and sharpening.  I might print that and hang it in my workshop for inspiration.

[Query]

Now I'm trying to come up with justification for this being a defensible work expense, haha.

Such pictures would make a great ad - if you wanted more sharpening business.

But since I think you said you don't, maybe it would be a great ad for a class on sharpening their own offered to your sharpening customers, so they use you less.

If you were closer to my location, I would love to take such a class myself.

[Kaitsu]

I have not done any edge honing but I have wiped blade with a towel.

Microscope is not mine, so in that means there is no reason to be jealous. Luckily I have access to this device since I would not use so much money to this device just due the skates. It provides quite nice photo quality, but still I feel its too expensive compared to needs what I have or where it can be used in skates sharpening. Most of the cases my phone camera provides enough good photo quality when I want to explain something for the skate owners. Here is link to photo which is taken with cell phone form the same blade. https://www.dropbox.com/s/la6l9ykqcb3sggh/Samsung%20S20.jpg?dl=0

I didn't have so much time to play with this microscope, but based on my experiences, its extremely difficult to get grinding burrs into photos. I would like to see them, but practice has shown that they are much more easier to feel than see. Example this photographed blade does have clear grinding burr, but I could not get in to photos. However I will still try that in better time, since I would like to have such a picture to my training material. Attached couple other photos which shows that its hard to judge what you actually see on them.

I have planned to photograph also some grinding wheels to see their grit composition, just for curiosity. I agree the statement what was mentioned in video what Bill shared that more coarse wheel does not automatically mean more coarse surface finish. My plan is to study also this during this year with measuring actual surface roughness values. Due the hollowed shape, this is not anyhow simple task and requires special device. Surface roughness measurement from the flat surfaces I could do any day without any problems.

[Query]

Your cell phone produces a pretty good image - probably good enough.

You must have a phone camera with very good, consistent close focusing. Mine can't do that.

Or do you use one of the clip-on microscopes or clip-on macro lenses that attach to cell phones? Some are pretty cheap, and I've thought of buying one. I've wondered if they work well enough, and whether they even could work, with the auto-focusing built into particular phone cameras.

I've had trouble imaging burrs too. You need to get just the right angle and distance.

I think part of the problem is that most optical microscopes have very poor depth of field. I.E., you need to be at exactly the right distance to be in focus. So My best attempts have only shown a tiny portion of the blade edge. I think I would love the 25-30x surgical microscope/telescopes some surgeons attach to their glasses, or wear as prescription glasses - but they cost at least a few hundred U.S. dollars, and the best cost more, so a surgeon said.

Someone told me that professional grade "inspection" microscopes sometimes have a larger depth of field - but are also quite expensive.

I've mentioned that I recently bought mail order eyeglasses from Zenni Optical for which I modified my prescription to focus best at 8 inches. That lets me see details better than my usual reading glasses, but I think I should have modified it to focus at about 2 inches to see even more detail. The problem is, they only sell strong prescriptions like that in lens materials that are a good deal more expensive than their usual lenses. Perhaps because they need a high index of refraction to reduce the distortion that a thick lens creates? And of course, it would be hard to take a good picture one could post on this forum through eyeglasses. And I'm not sure I could use eyeglasses that focus that close, because my two eyes would need to look in different directions to see on the same thing.

[Kaitsu]

Do you use one of the clip-on microscopes or clip-on macro lenses that attach to cell phones?

No, I do not use any clip-on macro lenses. Tripod or steady hands, manual focus and correct lightning are enough to get pretty nice photos also with my cell phone.

As promised, I took some microscope photos from the grinding wheels what I had easily available. I recommend to download the photo, so that you can zoom in.
Here is link to photo which is 10mb => https://www.dropbox.com/s/yl7vdsqh91co1ae/Wheels%20structure.jpg?dl=0

I have to say that this microscope is really nice tool, but unfortunate expensive.

[supersharp]

This verifies my expectation that the Blademaster ruby wheel is finer than the ICE fine. It creates a nicer surface finish on my machine, as long as it is balanced. Otherwise, there is too much chatter and the final product is worse instead of better.

[Query]

I notice what might be a semi-periodic pattern in the some of the pictures of the hollow, such as Katsu's "Hollow lashes or burr" image.

If you had to guess, is that a result of the way the abrasive grains are attached to the surface, or does the dressing device bounce as it dresses the grinding wheel? In the latter case, is there a way to eliminate the bounce, to create an even smoother surface?

Or am I wrong, and there really isn't a periodic pattern?

[Kaitsu]

I notice what might be a semi-periodic pattern in the some of the pictures of the hollow, such as Kaitsu's "Hollow lashes or burr" image.Or am I wrong, and there really isn't a periodic pattern?

Yes, there is kind of snake skin pattern which comes visible with camera or microscope. Surface which looks almost mirror finish by eye isn't anymore so shiny when you use enough high magnification. If you wonder how much this kind chatter pattern affects to the blade gliding properties, try to imagine same magnificated picture from the blade which looks terrible already by eye. As you can see from the linked picture, also different view angles changes quite a lot how camera lens sees details. I need to warn that file size is quite big.
https://www.dropbox.com/s/0ogf8oqyurd2mcq/Surfcase%20comparison.jpg?dl=0

Is there a way to eliminate the bounce, to create an even smoother surface?

If someone else than Query has some ideas how to get rid of this bounce, chatter, snake skin pattern or what ever it is wanted to be called, please share your ideas.
One solution would be use more coarse wheel, but that is not option is my case. In my opinion it would be just problem hiding. If I would like just to hide this issue from the camera lens, I could use some acid to make surface to be matt. Some kind of hand polishing is I guess needed, but how to make it without ruining just sharpened edges?

[supersharp]

We need a way to mount a hand-polishing cylinder in exact alignment with the grinding wheel, so we can use the skate holder to guide the blade along the exact pathway the machine takes.  If this could be reliably lined up, I think we could get a superior finish, but I'm not sure if the skater would be able to notice the improvement.  On compulsory figures, it would probably have been worth it.  Possibly not important for freestyle.

I would love to have those Matrix blades with replaceable runners just to be able to test a variety of different treatments on the runners.  Then you could change runners on one boot and see side-by-side if you feel any difference.  I guess I need to win the lottery to fund my skate sharpening research...except that I don't buy tickets (the only lottery we have in Alaska is the Nenana Ice Classic, once a year: https://www.nenanaakiceclassic.com/ which I also usually fail to remember to enter).

[Query]

We have no compelling reason at this time to assume that such very small differences in abrasion patterns - which are dominated by along track scratches - even matter. E.g., that they create significantly different drag,  along track, or cross track, or other effects.

I suppose you could even argue that the scratches increase surface area, so pressure is decreased. Ice physics seems to be a very complicated field, with relatively poor numerical models, including some arbitrary parameters. Some empirical literature in ice physics have shown that effective friction goes down when pressure decreases, but I'm not sure of the details. But if were true with constant weight (which I'm not sure of - maybe it is only true with constant area), the friction with along-track blade scratches might actually go down slightly, as completely unintuitive as that would be. I don't think we can know without actual measurements. And it probably isn't worth the effort, because ordinary skate techs don't go to the amount of work to create smooth surfaces that you guys are putting into this.

Or maybe the dominant effect would be to slightly increase cross-track friction, which might be a good thing, because it lets you push against the ice better. After all, increasing cross-track friction is the major point of having edges in the first place.

Or maybe the dominant effect would depend a lot on ice temperature and surface texture, the composition of the blades and the water used to make the ice,  the skater's weight and skating style, or what trick the skater is performing.

Sid Broadbent has a picture of a fancy jig on a lever arm, forcing a skate to move along a circular path across the ice. I don't know what he actually did with it, but I suppose he could have measured drag. Such a device could in theory be used to measure how various surface finish artifacts affect skating. Even if one did that, that is a pretty crude model of what happens during figure skating, which is a lot more complicated than gliding in a circle.

There have been a lot of attempts to sell people proprietary technologies to decrease friction in hockey skates. E.g., there have been attempts to heat blades, and there are the flat bottom V sharpening techniques. People give away the equipment to professional hockey teams, who maybe try them out. If what someone who used to work for such a team told me is correct, the professional teams usually drop them after a brief trial, but the advertisers still use their trial for advertising purposes, and don't mention that the technology is no longer in use by a significant number of professional players.

It seems to me that after a while, one should have some degree of skepticism about things that sound good, but might be insignificant or even counterproductive.

As far as how the blades look, it seems unlikely that spectators in the stands can see such minor imperfections in the hollow of the blade.

[Kaitsu]

This is how blades looks after ~60-70 hours of skating. Very typical example. Remember to pay attention to your skate guards cleanliness and choose wisely!

[supersharp]

Wow, that picture is amazing. I sound like a broken record(oops I guess that dates me, haha) because I'm constantly telling skaters to clean their guards and to replace them periodically when they have a lot of grit embedded in them...I'm going to show this photo to everyone that complains from now on.

[Isk8NYC]

This weekend, I bought a "corner grout cleaning" scrub brush at Ikea.  The bristles are angled and I think they'll work for cleaning out guards.

https://www.ikea.com/us/en/p/pepprig-scrubbing-brush-for-corners-70499538/

[marc]

j'ai un client qui était rectifieur /usineur (j'espere que cela traduit bien!)
il pense beaucoup que de polir avec une meule un peu comme celle là (après avoir affuter bien sur) rendrait super brillant la zonz affutée.
J'ai bien envie d'essayer. Pensez vous que cela pourrait être un secret de finition optimale?

I have a client who was a rectifier / machinist (I hope that translates well!)
he really thinks that polishing with a wheel a bit like this one (after having sharpened of course) would make the sharpened zonz super shiny.
I really want to try. Do you think this could be a secret to an optimal finish?

https://www.mototacot.fr/2842-414-kit-polissage-pour-l-inox.html

[Kaitsu]

As English in not my home langue, I have sometimes difficulties to understand clearly the difference between buffing and polishing. I guess buffing means polishing with felt wheel (more harder) and polishing is made with cloth wheel (very soft wheel). https://www.cmpionline.com/polishing-vs-buffing-the-differences

Nevertheless, Blademaster is selling 3" buffing wheels for blades polishing.  They promise following... "Gives a high sheen to the hollow of the blade without disturbing the skate edges".

https://blademaster.com/web/en/figure-skate-sharpening/2-3bw.html

I have always claimed to my selves and others how buffing wheel just rounds the edges. This even I have never even tried buffing wheel and even one of our ex coach said that one his coach in Canada was using buffing wheel. He said that skates did feel incredible good after the buffing. Since he moved back to Europe, no-one has ever been able to get same feeling to his skates anymore.

What an idiot I have been all these years when I have tried all kind of silly things to polish the hollow. I have tried diamond paste, tooth paste, ski waxes, universal stone and so-one, but I have never tried buffing wheel. This just and only because I believed to know how buffing wheel ruins my sharp edges. Thanks to Marc, today I decided to proof how buffing just ruins the edges. I took my metal buffing set, battery drill and started to polish the blade hollow  just by hand held. Surprisingly I didn't destroy the edges in seconds like I expected to happen. Actually I could see clear improvement on surface finish.

My buffing wheel was used and it had already some metal polishing wax which is hard to remove. Wheel was also meant for power drill so it was way too big to my sharpening machine. Preliminary results were anyhow so promising, that I decided to take my bicycle and go to local tool store to buy first 3" buffing wheel what I can just find. It was made for the wood polishing and not for the steel. Probably due this, it was maybe even too soft even it was felt wheel.  As it did cost only 3€ / 3$, I decided to try it. I have to say that I was amazed. I was really able to improve hollow surface finish without ruining the edges. Or at least this was the first impression when I tried the edges with my finger. Next step is that I need to find some volunteer whom is willing to test polished blades with the risk that I need to grind them again after the test. Maybe Supersharp is one volunteer even we are living in different side of globe 

It is for sure that I will order soonest buffing wheels from the Blademaster so that I can compare different buffing wheels. I will publish some video from my very first test during the weekend. Today I am too tired to start editing / uploading video to Youtube. Stay tuned on Youtube.

Marc, many thanks for challenging me!

[marc]

kaitsu,
je suis ému de lire ton commentaire au point d'en verser une larme.
Cette idée m'est venu de ce client qui par 2 fois m'a parler de polir avec une meule buffing ou polisching  avec de la pate de diamant.
je ne te voyais pas commenter mon post et je ne sais pas pourquoi, je pensais que tu aller essayer une meule à polir.
Mon gros problème était de trouver la bonne meule et grâce à toi je pense vraiment qu'il faut acheter la meule blademaster ( et ce qui me gêne c'est que je crois ne pas trouver cette meule en France!!)
Mon client m'a assurer que cela ne devait pas abimer les 'edges' et il me l'a répeter plusieurs fois et même assurer.
Il y a un petit mois de cela, à la patinoire du  stage de ma petite fille, j'ai fait connaissance d'un affuteur de patin de hockey qui me disait qu'au Canada ( équipe au plus haut niveau certainement) il polissait avec une meule blademaster mais je n'avais pas trouver la référence!
tout fini par se croiser ici et j'espère que nous allons faire une sacrée avancée dans la finition.
Je pense que Kaitsu, tu es le maître de l'affutage et tu nous le prouve par le post précédent et j'attens avant impatiente les prochains.
Je suis persuadé que tu doit arriver à la perfection.
Au plus vite!!!

kaitsu,
I am moved to read your comment to the point of shedding a tear.
This idea came to me from this client who twice told me about polishing with a buffing wheel or polishing with diamond paste.
I didn't see you commenting on my post and I don't know why, I thought you were going to try a polishing wheel.
My big problem was to find the right wheel and thanks to you I really think you should buy the blademaster wheel (and what bothers me is that I don't think I can find this wheel in France!!)
My client assured me that this should not damage the 'edges' and he repeated it to me several times and even belayed.
A month ago, at the ice rink where my granddaughter was training, I met a hockey skate sharpener who told me that in Canada (certainly the highest level team) he polished with a blademaster grinding wheel but I couldn't find the reference!
it all ends up coming together here and hopefully we'll make a big leap in finishing.
I think Kaitsu, you are the master of sharpening and you prove it to us by the previous post and I'm waiting impatiently for the next ones.
I am convinced that you must arrive at perfection.
As quickly as possible!!!

[tstop4me]

As English in not my home langue, I have sometimes difficulties to understand clearly the difference between buffing and polishing. I guess buffing means polishing with felt wheel (more harder) and polishing is made with cloth wheel (very soft wheel). https://www.cmpionline.com/polishing-vs-buffing-the-differences

The source you cited distinguishes between "polishing" and "buffing" as follows:  In polishing, the abrasive particles are bound to a backing material; e.g., consider sandpaper or an abrasive wheel (such as on your sharpener).  In buffing, the abrasive particles are loose and applied to a pad; typically, a liquid carrier (such as water) is used.  The size of the abrasive particles used in buffing is also less than the size of the abrasive particles used in polishing.

These definitions are not universal, however.  I was once trained in metallography.  When preparing samples for microscopic examination, the final stages typically involved polishing the surfaces of the samples.  A common apparatus is a rotary polisher.  A rotating platen is covered with a polishing pad (fabricated from a variety of materials, depending on the application).  And a slurry of abrasive particles in liquid (typically water, but sometimes not) is dripped onto the polishing pad.  For routine examinations, the final abrasive is frequently Linde B, an aluminum oxide abrasive with a particle size on the order of 0.05 micron.  That's damn fine; and we still called it "polishing".

I later went onto R&D work for even finer surface preparation of semiconductor wafers.  We used rotary polishers, polishing pads, and liquid-based polishing agents.  We still called it "polishing". 

[tstop4me]

Nevertheless, Blademaster is selling 3" buffing wheels for blades polishing.  They promise following... "Gives a high sheen to the hollow of the blade without disturbing the skate edges".

https://blademaster.com/web/en/figure-skate-sharpening/2-3bw.html

I don't get this.  You skate on the edges, not the hollow.  [Likely Query will inject himself here and point out that if the ice is very soft (such as in an indoor rink with a defective chiller, or in an outdoor rink during warm weather), you will skate on the hollow.  To which I will respond:  "If you're skating on slush, the surface finish of your hollow should be waaay down on your list of concerns."]  If you skate on a flat and look at the tracing on the ice, you will notice two thin lines spaced apart:  an inside edge and an outside edge, not one thick line with the thickness of the blade.  Even with a deep single edge, the thickness of the line does not approach the thickness of the blade.

Let's put aside the semantic difference between polishing and buffing.  For simplicity, I'll use "polishing" (for reasons I explained above).  The purpose of polishing should not be to improve the surface finish of the hollow per se, but to improve the surface finish of the edges, which of course includes the peripheral regions of the hollow that form the interior surfaces of the edges.  There's no point in merely polishing the bottom of the hollow for cosmetic reasons.  Polishing the hollow should, of course, not degrade the edges.  But to have value, it should disturb the edges; i.e., improve the surface finish of the edges.