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Wissota powered skate sharpener review

Started by Bill_S, November 04, 2019, 06:55:19 PM

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Bill_S

I purchased a Wissota model 911 deluxe last week. This model includes a pedestal base and dust catcher. I had them substitute the standard skate holder for the figure skate holder for a $50 up-charge.  I also purchased an edge level checker, and a 100-grit grinding wheel for figure skate blades.

This thread will be about my experiences setting it up and learning to use it.

The packages arrived today, and the UPS guy needed a little help getting it all out of his truck. After he deposited them curbside, I used my own hand cart to wheel them around the house to the lower entrance closest to my shop. A couple of these boxes are SERIOUSLY heavy.



After lots of huffing, puffing and wriggling through to the shop, I managed to get things unpacked. Here is the sharpener itself. It was mounted to a piece of plywood in the bottom of the shipping box.



I felt that it's weight would be manageable for a fit fellow to use on a workbench, and then move out of the way when not needed. It's not light and it would be a chore, but doable. However, I purchased the Deluxe outfit with a pedestal base to mount it on. I made room in my workshop for a permanent installation, and I will have dust collection for grinding.

Here's the figure skate blade holder. It clamps onto the stanchions to properly do side-honed, parabolic, and tapered blades. It can't do Revolution blades, and the standard holder is said to be suitable for them.



[continued in next post]

Bill Schneider

Bill_S

I mentioned previously that I purchased the 100-grit wheel for carbon steel figure skate blades. I exchanged wheels before I attached the sharpener to the pedestal base. The standard pink wheel is said to be suitable for stainless steel blades, especially hockey blades.



After buffing rubbing compound on the table surface for a super-smooth surface, I applied some automotive paste wax to it. These steps will allow the felt pads on the bottom of the skate holder to slide with less friction.



I mounted it to the pedestal base with no problem. The combined weight is very heavy, and it doesn't budge. The motor runs very quietly and smoothly.



Sorry for the cluttered state of my shop, but I don't have many square feet available. It's somehow appropriate that this grinder is on the back side of a table holding a standard bench grinder, plus a slow speed, water-bath sharpener for woodshop tools and knives.

I quit work tonight in the middle of attaching the red dust collection hood to the sharpener. The fit is off, and I'm going to have to re-drill some mounting holes in the hood to get it to fit properly. That's been the only wrinkle in getting this set up.



I'll spend more time working on it tomorrow, then move on to sharpening some blades.
Bill Schneider

Query

>Here's the figure skate blade holder.  It clamps onto the stanchions...

As best I understand it, the stanchions are the thin vertical support elements. Is that what you mean? Or does it clamp onto a longwise element?

Does it clamp onto the blade in such a way as to de-warps it temporally while you sharpen it? If so, that is a big plus.


tstop4me

"I mounted it to the pedestal base with no problem. The combined weight is very heavy, and it doesn't budge. The motor runs very quietly and smoothly."

Is the unit stable in a free-standing configuration, or does the pedestal base need to be anchored to the shop floor?


"I mentioned previously that I purchased the 100-grit wheel for carbon steel figure skate blades. I exchanged wheels before I attached the sharpener to the pedestal base. The standard pink wheel is said to be suitable for stainless steel blades, especially hockey blades."

Do the wheels interchange readily?  That is, any fussing with centering and balancing required?

Query

An Example of a crude rocker guide that might work, but needs a re-design by someone who has better mechanical intuition than me:

You have already figured out how to trace the edge of a blade onto a piece of paper, to record the rocker profile. Great!

Now do the same thing using an Xacto (or other brand small thin) knife on a flat piece of stiff cardboard, to create a thin guide piece. This will be your "guide". Tape or clamp this piece underneath the blade or blade holder, 1/10" or so back from the edge, parallel to the edge. To verify that it is parallel, use a measuring tool, like a calipers, micrometer, or maybe just an adjustable divider, or nut on a bolt, to verify that the distance to the edge boundary is the same at both ends.

Tape or attach a "stop" on the flat surface on which the blade holder slides, next to the grinding wheel, but 1/10" back. It can even just be a piece of thick tape, stuck onto the surface. The thickness should be chosen so that the piece of cardboard, or whatever, touches it and is stopped by it, and never touches the grinding wheel, but the blade holder or blade passes over it.

Thus you can slide the blade or blade holder on the table against the stop. It will follow the established  profile, and allow the wheel to grind the blade in the same rocker profile it already had.

Actually, you should reverse the order of attaching the guide and stop. Attach the stop first, and leave it there, then position and attach the guide, using the measuring instrument, to make sure you will only remove .001" (or whatever amount you want to remove) of metal.

Can you figure out a way to make that more practical? I admit that cardboard would wear out too quickly to last very long. Are there soft plastics, real or artificial leather, or some other material, that would retain their form, yet be easy enough to cut precisely?

Also, is there a practical way to cut it with a modified shape, if you wanted to modify the rocker profile? E.g., could you grind the edge of the guide, instead of the blade, to the shape you want, until you have it just what you want? I'm fairly certain that cardboard wouldn't hold up to that without distorting, but maybe one of those soft plastics or other materials would.

Another plausible way to create a modified profile: There are "Cricut" brand automated fabric cutters, which follow a computerized pattern, available in fabric shops.

  https://cricut.com

The idea is to have it cut the guide, instead of using a hand-guided knife. I've never used one. I'm not sure if you can create your own pattern for Cricut machines, and whether the pattern can be curved. I'm also not sure if they can cut a thick enough piece of reasonably stiff material (e.g., real or artificial leather) to guide your blade against the stop. But if they can, that would be a very neat way to do it.

If you are really ambitious, let's try to modify the toe pick: When you cut the guide, cut against the toe pick shape too, so the guide includes the toe pick profile. Tape or attach another stop on the table-like flat surface on your bench grinder.  Use that and the guide to cut the toe pick. I can't figure out how this could work with cross-cut toe picks, but many blades don't have them.

However, there are problems with re-grinding toe picks: the existing teeth (picks) are at an angle, which means that when you grind off the material, you are left with thinner teeth, because part of where the new teeth would be has already been cut away. If you care, you might need to modify the toe pick shape in some way.

Anyway, I leave it to you guys with real mechanical intuition, to figure out a better way to do these things. I admit it is very crude, and I'm sure you can think of something better.

Bill_S

Query:

1) If I were to dive into shaping a blade, I'd template-route a pattern into Masonite using a desired blade as the master shape. Look up template routing on the web - it is easy to do and very accurate.

2) The original holder would be better for holding a blade straight while sharpening. It grabs the skate by the runner, but of course, it can't to tapered, parabolic, or side-honed blades. That holder is said to be the one to use for Revolution-style blades. The figure skate holder that I have will probably straighten less. I might get a handle on this later with some measurements.

tstop4me:

1) The base has rubber feet from the factory, and doesn't appear to require bolting to the floor. However they warn that hanging accessories off of the side of the machine could cause an imbalance and require bolting. It would take a heavy accessory to require that. So far, I haven't bolted it down and the rubber feet are supporting the assembly. If I push against the machine firmly, then the rubber feet "squish" a bit and the top will move. That's quite a push though, and the ounces of pressure used to move the skate holder won't even come close.

2) Changing the wheels is very easy, and someone could do it in 2 to 3 minutes tops. Unscrew the two red knobs that hold on the top, and lift it off. Unscrew the nut on the arbor, and swap wheels. Tighten the arbor nut, replace the top and tighten it. The wheel dress will center the wheel. There is no balancing step needed.

Here are a couple of photos that I made while changing the grinding wheels that show this area closely:





Bill Schneider

Query

Quote from: Bill_S on November 05, 2019, 07:55:50 AM
1) If I were to dive into shaping a blade, I'd template-route a pattern into Masonite using a desired blade as the master shape. Look up template routing on the web - it is easy to do and very accurate.

OK, at first glance that does look like a better method to create the guide, provided you have the router, which I assume you do, than my idea of tracing the original blade with a knife.

On these pictures: https://en.wikipedia.org/wiki/Masonite it looks like the edge of Masonite is pretty rough - will it be ground smooth enough by the router bit to make a good template for a blade? Is it's smoothness a function of the grain size, which looks pretty large in those pictures?

Also, unless the router bit can cut the hardened steel used in figure skate blades, without being significantly ground away while processing the blade, you still need to use the guide and sharpening machine to transfer the profile to the new blade, or to shift its position by .001" or so on the current blade, because you need to remove that much steel to make the new edge. Plus, the sharpening machine is still needed to grind the hollow.

Is the method I proposed for using the guide to guide the blade against the sharpening machine OK for doing that? I admit it seems pretty clumsy and slow, because you have to measure and shift, measure and shift, over and over again, until you have the guide precisely parallel to the old edge, then tape or clamp it in place. The major reason to use a powered sharpening machine is to reduce the time to sharpen blades.

Quote from: Bill_S on November 05, 2019, 07:55:50 AM
2) The original holder would be better for holding a blade straight while sharpening. It grabs the skate by the runner, but of course, it can't to tapered, parabolic, or side-honed blades. That holder is said to be the one to use for Revolution-style blades. The figure skate holder that I have will probably straighten less. I might get a handle on this later with some measurements.

I'm not sure the part of the blade that is clamped by the holder is the part that is tapered, parabolic or dovetail cut side honed. In particular, though I may be wrong, it may only be the "chrome relief" zone at the very bottom that is ground in that way. If so, the holder may be able to hold all of these blades without any issues. Even if I'm wrong, if you attach compressible foam sheets to the parts of the holder that grip the blade, I think that might handle those blade shapes. I have never measured the thickness of one of those blades in detail, and don't know what parts of the blade are actually shaped that way. It might even differ by brand or blade model.

Any way - good luck on your experiment! Because you have good mechanical intuition, you may be able to learn to do a great job as a self-taught machine sharpener. All the local discerning skaters may come to YOU to get their blades sharpened.

I assume you still intend NOT to learn machine sharpening on your own good blades, but to start with someone's throw-aways. A lot of rinks throw away old rental skates and blades after a while, and pro shops also get peoples' old discarded blades that they might give you free or cheap. Or maybe another skater has a few they don't want anymore. If you can't get them free, many thrift stores and used sporting goods stores have a few worn out skates and blades fairly cheap that you can practice on. Even though you obviously have good mechanical intuition, I think you will find the initial learning curve very steep on powered sharpeners.

Though I admit that I've only spent an hour or two trying, and wasn't satisfied with the results. The biggest problem I ran into was that I used a blade holder and machine that wouldn't let me adjust the height, and therefore the centering of the grinding wheel, against each end of the blade, in a gradual measured fashion. I had to loosen it, shift the blade by hand, and re-tighten it, then place it against the grinding wheel, over and over. Even if you use precision calipers to test the blade position, that is a super-slow way to center the wheel on the blade. Does the Wissota holder or table adjustment have a better way to level and center the blade on the wheel?

Based on your pictures, there isn't a good way to protect your eyes from the steel filings, abrasive particles, and sparks that will fly off the blade and wheel. If there isn't one, you may want to get some really good eye safety goggles, or even a welding mask. Or add some sort of Lucite or similar material sheet that blocks your eye from being hit. You may even want a way to protect your hands and arms, though that would hard to do - I guess gloves are very dangerous things to get near a rapidly moving part. How do you deal with these things on a bench grinder?


Bill_S

I intend to get a handle on plain, old-fashioned sharpening first before any reshaping experiments.

I did take a photo of my skate in the figure skate holder. There is leeway where to clamp, and it's shown clamped closer to the blade's edge in this photo.



I spent a lot of time yesterday attempting to fit the dust hood to the machine. It had problems that would prevent someone without many tools from mounting it properly. Part of it interfered with the base where the motor mounted.



In that area, I ground some of the hood away using my bench grinder, but that cut away the fold of the doubled metal edge. That might weaken the part, so I put in pop-rivets to hold the metal flap in place..



It still wouldn't mount properly. The bottom of the dust hood should be below the table of the sharpener, but the mounting holes were too low. That made it impossible to be mounted flush with or below the table. I marked positions and used a Roper Whitney Jr. sheet-metal punch to put new holes above the original ones to allow the hood mount properly. A little work with a file blended the two holes into a slot when I was done.





It finally mounted correctly, and is now sitting about 1/16" below the table surface so the skate holder won't bump into its edge.



The next challenge with this part is to provide a vacuum port suitable for a real dust collection system. Wissota installed a sink drain instead of a real dust port.





The flow area is small, so the sink drain will make a lot of wind noise with my shop vac. I suspect that they chose this part to work with smaller shop vacuums. It's a strange substitution especially because a plastic dust port for a larger vacuum like mine plus a reducer for smaller vacs would probably be cheaper than what they used. I am going to drive to Parkersburg for a $4 part to adapt my own vacuum. I'll enlarge the existing 2" hole in sheet metal to 2-1/2" to mate with the new part. I believe that I have a 2-1/2 chassis punch somewhere around here to do that.

The dust collection hood needs some serious redesign! Wissota, what were you thinking?

If you aren't handy with tools, don't buy this component.


Bill Schneider

Bill_S

I ran into another issue with the sharpener itself. It's not a show-stopping problem, but not ideal.

A new grinding wheel has a flat edge. You use the diamond wheel dressing feature to put the radius on it. Before I dressed the wheel, I swung the dressing rod up and down, advancing it slowly until it just touched the wheel. To my surprise, it touched the bottom edge of the wheel, but when swung upward, still had a way to go to reach the top edge. The illustration below shows, from top to bottom, 1) the situation I encountered where the dresser touched the bottom edge first, 2) the offset crown that would result, and finally, 3) a properly setup diamond dresser.
[Click to enlarge]



If not extreme, an offset crown could still sharpen skates OK, but getting even edges on the blade will be more difficult to achieve.

There is an adjustment that is factory-set for the pivot height of the diamond dresser. There is no mention of further adjustments in the instructions. The adjustment mechanism is a plate that rotates around a split pin. The plate is slotted on one end for a locking bolt and has a recess on the other end for the diamond dresser arm pivot. (Note that the photo below shows the mechanism itself, but I had already fixed it and dressed the wheel. I was too busy troubleshooting to photograph it when I first discovered the issue.)



The factory setting was incorrect for centering the dressing arm pivot on the wheel. I loosened the bolt and swung the adjustment plate to lower the pivot height, then attempted to lock it in approximately the correct position. That's when I discovered the probable cause of the misaligned plate. The bolt used was one with a serrated underside like this...



The bolt serrations would grip the plate and rotate it back out of position when tightening it. It needed a washer underneath to reduce that tendency. I added one, tightened the bolts, and gave the new wheel a proper dressing. It worked!

The choice of bolt and the lack of a simple washer in the construction led to this. I can think of a number of possible scenarios that led to the decision to use serrated head bolts and eliminate washers, but that inadvertently caused this particular problem.

If you think that this is a problem with just Wissota sharpeners, you're wrong. Every complex tool that I get into the shop gets a good inspection, and you'd be surprised at how many things that I've found that need to be corrected.

Bill Schneider

tstop4me

It's bizarre that they saved a fraction of a cent on the washer, but installed a more expensive drain fitting.  I'm glad you were able to repair the hood yourself, and didn't have to ship it back.  The defects are disappointing, but no one can carp about shoddy Chinese manufacturing in this instance.  :-)

Bill_S

True.

There are issues, but the unit has nice "bones" from which to improve. That motor in particular is a wonderful unit. It's a Leeson motor. I used those (and Baldor motors) in industrial designs back in the 80s.
Bill Schneider

Bill_S

I did some quick calculations for consumables when sharpening. Consumables include the grinding wheel plus the diamond wheel dresser.

Rough estimates from Wissota's claimed life of parts (200 pairs of skates for a grinding wheel and 400 pairs for a diamond dresser) show about $0.25 for the wheel and $0.13 for the diamond dresser when doing a pair of skates. I included shipping charges into the estimate.

I'll set aside a "tip jar" and put in $0.38 for each pair of skates that I sharpen.
Bill Schneider

Query

I'm rather disappointed that your new machine needed some work to make it work. I guess Wissota is pretty near the bottom of the line in terms of machine cost, unless the Chinese ones I pointed out to you earlier would actually work.

Ummm. I did some calculations a while back and concluded that one of the most expensive part of sharpening of good quality figure blades can be the metal (and therefore lifetime) you take away from the blades. Let me update prices:

I estimated that you substantially alter the properties of the blade when you remove about .1 inch, because you get a somewhat different interaction with the toe pick - and that's assuming you carefully trim the toe pick down near the end of life. So, on a $500 blade pair (the approximate cost, discount mail order of MK Dance - and that doesn't allow for potentially returning warped blades), every .001 inch you remove is $5. I had been told that a very good skate tech would remove about .003 inches, which is $15. However, I have started to think that even with machine sharpening, a really good tech, using a fine grain wheel, can often get away with somewhat less than .003 inches - at least on figure skates, so maybe it isn't that bad. Also, you have chosen less expensive blades than that.

As you know, you can frequently get away with just removing .001 inch of metal with a hand sharpening, because to some extent you are reshaping the metal at hand sharpening speeds, rather than just grinding it away. It was very easy to calculate that sharpening your own makes sense on an economic basis, if you are willing to learn.

On top of that, it seems like a typical very picky figure skater drives 2-10 hours round trip to their favored skate tech to get their skates sharpened. If you assume that is at an average of 50 miles/hour, and $0.50/mile (including incremental cost of maintenance, repairs, depreciation, accidents, insurance...), that works out to $50 - $250 / sharpening. So, if, as assumed, you aren't happy with the skate tech at your favored skating rink, driving is even more than the loss of metal - and it applies even if you use somewhat less expensive blades. (On top of that, many skaters feel they need to buy a skating session local to that to verify that their tech did a good job on their blades.) Also, some figure skaters carpool to their skate techs, or send their skates with their coach, who brings other skater's skates at the same time.

Needless to say, it was easy for me to show, if I included driving costs, that sharpening your own can make even more economic sense. Despite that, I have convinced very few skaters that sharpening their own makes sense. Most don't believe they can learn to do that, or that it requires very expensive tools.

Of course, since you are sharpening your own, the driving cost completely goes away, whether you do it by hand, or with your Wissota machine. I hope you end up happy, despite having to make modifications. Alas, in your case, you were already sharpening your own by hand, so the cost savings is hard to argue here. But I guess you could argue that you love working in your shop, and that you may actually enjoy figuring out how to make the Wissota work, so all this may just be extra play to you, and may be worth the cost.

Does the exact position of the crown matter? In the end, you end up adjusting the height of each end of the blade, so as long as the wheel is significantly wider than the blade, how would the position of the crown make a difference?

Bill_S

Yes, you can sharpen skates with an offset crown. It would probably require a few more test "touch" cuts to adjust the skate holder to the proper height.

But if the crown is centered, then you can eyeball the blade against the center of the wheel and be very close. And if you just do your own blades repeatedly, set it and forget it.

However I may be switching between thinner dance blades and regular freestyle blades. That always requires some adjusting of the skate holder. The clever magnetic dials on the Wissota skate holder elevation screws will help with switching, and I will create a chart for settings to use for various blades.
Bill Schneider

Bill_S

The dust collection hood is now ready for usage.

This photo shows the new dust port that standard 2-1/4" Shop Vac hoses fit into. Also in the photo is the chassis punch tool that I used to enlarge the hole in the dust collector to 2-1/2" to fit the port without choking any airflow.



Chassis punch in the original hole, and being positioned...



...and the hole is now enlarged.



The port had four mounting screw holes, so they were marked for drilling into the hood. I attempted to punch the holes with the Roper Whitney, but the 2-1/2" diameter hole was too small for that tool to fit through. I had to drill them. Drilling sheet metal is a pain, but to make it go a little better, I clamped a small wooden backer-block underneath. The holes aren't as clean as punched holes, but will certainly work. They are underneath screw heads and washers too, so it matters little.



I mounted the new dust port to the hood, then attached it all to the sharpener. Top view...



Bottom view, with an elbow added...



It's ready for operating now.
Bill Schneider

Bill_S

I used my old skates that I bought in 1977 to practice with. They were in pretty bad condition, so there's nothing to lose using them for practice. One blade had TERRIBLY uneven edges that you could see just sighting down the length of the blade. And to think that I used to skate on that!



In this photo there are two magnetic pieces. One had the magnet positioned to be attracted to the edges themselves, the other has a magnet that attaches to the side of the blade. If edges are uneven, then top of the edge piece doesn't align parallel with the engraved lines. You can see for yourself how bad this sharpening was. That's the stuff some people pay for!

The steel blade showed its age too.



Onto the sharpener!



I have a toe pick protector fastened onto the pick in this photo. It loosened and fell off after a while, so I proceeded without it. That's when I discovered how easy it is to nick a toe pick. I paid very close attention after that!

After I got the hang of it, the sharpener did a marvelous job. It's very, very smooth in operation, and that keeps chatter on the blade to a bare minimum. I got some of the smoothest edges I have ever seen, even when compared to my hand sharpener. Excellent!



Learning to set up the skate holder for even edges takes some careful thinking. I have to visualize the geometry of the cutting wheel in relation to the blade, and make small adjustments to the skate holder. I have to stop and think about it each time so far, so I am going to make a small chart to show directions for adjustment to save time later on.

I spent about an hour experimenting, but by the end, I was presented with this...



The sharpener's maiden voyage went better than expected!
Bill Schneider

tstop4me

Congratulations, Bill!  Did you use sharpening wax on the final pass?  If so, did it improve the surface finish significantly? 

Query

Congratulations!

Obviously, you could have used duct tape instead of creating a custom dust port fitting. But I guess the advantage of the way you did it, is that you can rapidly remove and reinstall your shop vac from the sharpening tool, and use the shop vac for other things the rest of the time.

I have rethinked the suggestion I made that you could have adjusted the heights of the blade to create a centered scratch (if you scrape the wheel against the blade when the wheel isn't turning) instead of recentering the tool. I'm not quite right. Being able to make a centered scratch doesn't guarantee that the exact center of the ground hollow arc is exactly along the centerline of the blade. Not only would missing that centerline mean that the edges were of slightly different heights, but they would be of slightly different shapes. I'm not certain how important that would be, and I'm not even sure how to measure the position of the arc center with inexpensive tools.   

You learned much faster than  me (in fact, after an hour or two on an old Blademaster, I still wasn't happy). If the Wissota has good height adjustment, that would have helped a lot. There was no way with that very old Blademaster blade holder to make small adjustments in a controlled fashion. It was trial and error, every time.

I'm guessing that all your experimenting took off far more than the .003" or so of metal that many high end skate techs say they remove with figure skate machine sharpening tools.

One question is, if you were to do it again (e.g., by deliberately dulling the blades, measuring them, sharpening, and measuring again), how much would you need to take off to do a good job?

Also, have you measured how consistent a rocker profile you managed to create? And what shape and placement rocker-transition-point (which I have previously called a sweet spot, but tstop4me has possibly convinced me that is too ambiguous) you created? I know this is a completely unfair question - you have just gotten started, and you may want to get more practice before testing such a complex thing. Many "professional" skate techs don't even get the edges even, and have a poor idea of maintaining or creating a desired rocker profile, after years of work, and you have already beaten them out in a mere hour on producing even edges.

Also, do you by any chance have a microscope (or even a very high power magnifier) that lets you see how ragged the edge is at a small scale?

If you have a "Roper Whitney" tool, with cutting devices added, your setup goes significantly beyond what I think of as a "wood shop", in the direction of a (metal-working) machine shop. This somewhat confirms to me the observation I have made that the best skate techs tend to have had extensive previous shop experience to draw upon, in part because it has been so difficult to get good instruction on how to be a good skate tech. I once asked Mike Cunningham whether he would be willing to train me as a skate tech. He said that he wouldn't be in business long enough - that it takes at least a few years of training and experience under a master to learn to do it well. Of course that is partly adapting to various people's anatomies, and figuring out what people need to learn specific skating skills. Nonetheless, you are making very rapid progress. Maybe pretty soon you can hang out a shingle with your shop logo, and become the premiere skate tech of your own multi-state area!


Bill_S

tstop4me: I did not use the sharpening was at this point in my experiments. Once used, the wheel needs to be re-dressed before the next pair of skates. I'll try that later, but the fresh metal is very smooth even without it.

query: My shop vac (+ Dust Deputy cyclone separator) gets passed around to the table saw, the band saw, the router table, and sander, plus I attach the floor sweep gizmo for after a day's work is done. I must have a way to move the hose around, so using duct tape or even hose clamps wouldn't work out. As a bonus, I get a larger opening for debris  in the sharpener's dust hood.

I quickly realized that a simple "touch grind" would not work if a blade already has uneven edges. I made the mistaken assumption that the old skates, ground "professionally" would have even edges. I was getting very odd contact points at the front and the rear of the blade, and it was during that period of head-scratching that I took a look down the blade. What I saw was astonishingly uneven to the naked eye, without any edge checking devices. The severely high edge made contact first even though the blade was centered on the holder. I was furiously cranking dials for the first few minutes even though I set up the holder with a set of measurement calipers. The light went on after a few passes with odd results.

I'm sure that I took off more than 0.003". However judging by eye, it's less than I expected for so many grinding passes. I should have measured first to see how much was actually removed, but that's water over the dam.

Measuring rocker profiles (as opposed to tracing) takes over an hour of labor for each blade tested. Having a new toy, I didn't want to take the time to measure old, junk blades. That doesn't completely forgive not tracing them though.

I'll see what I can do for an extreme close up of an edge. In the meantime, I want to work on a modest chart or system to quickly adapt to different blade thicknesses for centering on the crown. I'll bet a dollar that's where most sharpening techs struggle.

Bill Schneider

Bill_S

Here are some close-up photos of the freshly sharpened blades. I used a 60mm Nikon macro lens for the close-up, then cropped in on the photo to show the area of interest.

[Click to enlarge the photos]



This one shows a fine "wire edge" partially detached from the blade edge. One wipe and it's gone.



Bill Schneider

Query

Cool picks. Pretty high end lens and camera. But at that angle, you can't really see the edge, though the wire off to the side is interesting. I think you see it better in shots taken from one end, almost parallel to the edge, so you almost see a cross section, like the bottom picture in

  https://scienceofsharp.com/page/5/

And you can see the raggedness of the height of the blade in shots from the side, like the side view shot in

  https://scienceofsharp.com/page/13/

(Those are electron microscope pictures, at a higher magnification than your macro lens can manage, but I hope you get the idea.)

But maybe this is too early to be showing close-ups of your edges. I'm sure you will get even better with time.

tstop4me

Quote from: Bill_S on November 10, 2019, 08:14:17 AM
In the meantime, I want to work on a modest chart or system to quickly adapt to different blade thicknesses for centering on the crown. I'll bet a dollar that's where most sharpening techs struggle.
Yeah, a couple of skate techs have let me watch, and I've seen several videos by skate techs on YouTube.  Surprisingly, they don't use measuring instruments.  They eyeball settings, perhaps put ink on the blade, make test cuts, check results, make adjustments on the skate holder, and iterate.

None of them approach the process the way a machinist would.  If you center the crown on the wheel as you have, measure the thickness of the wheel, and measure the height of a reference surface of the wheel above the flatbed, you can determine the height of the crown above the flatbed.  Then if you measure the thickness of the blade (and perhaps some other measurements depending on the specific blade geometry), you can calculate the target height of a reference surface of the blade above the flatbed such that the central longitudinal axis of the blade aligns with the crown.  Also, by checking the heights of the blade above the flatbed at several points along the blade (depending on the specific blade geometry), you can set the tilt adjustments of the skate holder to align the blade properly.

tstop4me

Quote from: Bill_S on November 10, 2019, 11:20:34 AM
Here are some close-up photos of the freshly sharpened blades. I used a 60mm Nikon macro lens for the close-up, then cropped in on the photo to show the area of interest.
This one shows a fine "wire edge" partially detached from the blade edge. One wipe and it's gone.

Other than the stray wire edge, there were no burrs along the edges that required removal with a honing stone?

Bill_S

Edit: tstop - your second post above arrived while I was typing this one referencing your first post. I'll add another post about burrs.
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Well, I did essentially that today. I thought through the process and made some notes along the way. The repositionable magnetic scales in the height/tilt mechanisms are attached to 1/4-28 screws. Each turn of a dial then advances or retracts the holder 1/28th inch, or 0.036". The dial has 1/16 divisions around it's circumference. That means that each division raises or lowers the blade 0.0023" (0.036"/16).

I made a chart with that information along with which direction to make adjustments based on the reading of the edge level checker.



It's now taped to the dust hood until my memory kicks in.

I had zeroed the magnetic dials for my old Riedell skates.



The blades for the old Riedells at the clamping area (close to the stanchions) varied in thickness from 0.149" to 0.152".

In a moment of optimism, I elected to sharpen my current Ace blades that I currently skate on, but their thickness at the clamp area is a thicker 0.161" - 0.163". That requires an adjustment of the skate holder to accomplish even edges. The difference between the two blades was approximately 0.010". Half that amount is required to keep the blades centered, so I dialed in 0.005" downward into the holder. After two cutting passes with no further change in the holder, I saw this wonderful result...



Hallelujah! The math worked! I was over the top with joy! Boy, am I having fun!

When previously deciding which sharpener to purchase, I did a little scale diagram to see how far back from the pick that I could sharpen with the Wissota's 7 inch wheel. The diagram in this thread http://skatingforums.com/index.php?topic=8357.0 predicted a 0.7" dead zone where I couldn't sharpen. Here's what I got today...



Good heavens, the prediction was right on!

I use sharpening wax on one blade to compare to the other. When wax is applied, it is suggested to cut in the same direction as the cutting wheel, moving slowly.



I could see the wax was melting near the cutting area. It made a very slight difference on my blade. It's so slight that I probably won't use it. Usage requires re-dressing the wheel each time because of build-up on the wheel. It's easy to see where the wax was here....



Color me skeptical if you wish, but I think that the wax might be a way to sell more grinding wheels with all the required re-dressing.

There is one little thing that I will keep in mind. The wax could be seen melting where the wheel touched the blade. Perhaps it will prevent the steel from losing temper along the edge because the wax melting and evaporating might keep the steel a bit cooler. That would affect edge life, not finish.

I am extremely happy with these results. The blade is as smooth as a baby's bottom, and it's easy now to accommodate different blades with this sharpener. I'll have happy dreams again tonight!

BTW, I used a 7/16" ROH for these blades to split between the Pro-Filer's 3/8" and 1/2 ROH", both of which I've tried.

I'll be up early tomorrow to skate on them. The dance blades will have to wait a bit longer.
Bill Schneider

Bill_S

tstop - there is a slight burr, but it's much less than I got with the Pro-Filer hand sharpener. It's detectable in some places along the blade, but not in others. I'm using the fingernail test to find it.
Bill Schneider