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I had to repost the image above due to some calculation errors. http://s20.postimage.org/pwus1ifnx/hollows.jpg To answer your questions AftonDad, I essentially looked at a skate blade, although it wasn't a skate blade. Basically, I dressed the wheel, touched a block of stainless steel that's wider than a skate blade, up to the wheel. Then profiled the hollow in the ss. The profilometer doesn't like large drop-offs, plus I wouldn't be able to get a skate blade vertically under the stylus. There wouldn't be much point in profiling the wheel itself because that's way too rough and only looking at one small cross section isn't what happens. The resulting finish is due to the entire wheel passing over the blade, so it's a cumulation or summation of the entire grinding wheel surface. I did look at a couple different sections ground with the same dressing, and they all looked pretty much the same. The 100/50 spinner was used to dress a wheel maybe 10 times. On the 1/2 spinner, it's dressed many more, probably 40 times. I can look at just about any profile like this, I just don't have access to just about any profile.

For what it's worth, I have access to an atom-scale profilometer and got profiles for 1/2" and 100/50 cuts made with mini-spinners on an X-01. I thought I had a 90/75 spinner but can't find it. Can try to compare to other hollows. ARGH, I'm reposting the image due to some conversion errors between angstroms, microns, inches and mils. I ended up doing it the old fashioned way with pencil, ruler, and calculator. The dimensions are more surprising overall than it was the first time around. http://s20.postimage.org/pwus1ifnx/hollows.jpg The FBV 100/50 is actually only about 0.082" across the flat. A stylus tip radius of 9 mils would account for this, however the stylus radius is only 1mil. The flat also isn't very flat. It's not as deep as circular hollow which is the intent. The depth for a 0.114" skate blade would be 0.93mil, which is a bit more than the 0.50. If I had to put a number on the spinner, and accounting for a finite stylus radius, I'd guess my 100/50 is more like an 85/85, and as always the second number will change with a thinner/wider skate blade. The 1/2" spinner has a hollow depth of 2.6mil. If my calculations are right, a 1/2" r.o.h. should be 3.3 mils deep. The 2.6mil depth, assuming it's circular is more like a 5/8" r.o.h. That's surprising, I would have guessed the spinner would have a smaller hollow. If the spinner started with a 1/2" hollow, and diamond dust was added to it, that should make the radius slightly smaller. Maybe that's accounted for a little bit (or too much). The Wissota 1/2" hollow is almost identical in shape however overall it's bit smoother. Surprisingly the hollow depth is only 2.3 mil, which (again if my calculations are right), is more like a 0.7" r.o.h. Maybe the sticker wasn't placed on the diamond dresser exactly where it needed to be.

Wow, no need to all testy here, I'm an engineer and what's proposed makes sense to me. IMHO, if you can't sharpen skates without compressing the felt noticeably, you shouldn't be sharpening skates. There are plenty of other factors like vibration and tolerances in the sharpener that are pretty minimal to the overall effect of FBV. Not looking for six-sigma results here, just more information would be good to see since it's pretty lacking. I seem to remember Blackstone was going to post results from improvements in skating speed due to FBV, any word on that?

The method on how a shape is applied to a grinding wheel? just google "diamond roller dresser", it's already been around for years, maybe centuries and yes, there are plenty of patents for them. I think Blademaster is being petty, but they do make some interesting points. I do believe Blackstone is not accounting for some things, like how the shape of the spinner changes after adding the diamond dust. I've noticed their 1/2" spinner hollow is really more like 7/16". Similar things will happen with the FBV, the flat part will become shorter. Is "thou" a technical term? I believe 'mil' is the standard term for a thousandth of an inch. BFD = big f****** deal FBV = for blackstones vitality FBV or BFD won't make you a better skater, skating more makes you a better skater.

There's a little bent washer that creates the pressure on the spinner. If you call Blackstone they'll say to try and jam something in there to try and flatten the washer so it creates less pressure. Not such a great design to have a spinner that doesn't spin, or that has to be turned by hand so it doesn't eat through one spot on the spinner.

I can come at the wheel from the front or the side, side give much more control because of the angle. I can just barely graze the grinding wheel and the spinner will start to spin. I can then let go of the skate holder, and wait for the spinner to stop spinning. No problems with wheel unbalancing, in fact this is the way to dress most grinding wheels to 'true'

I've actually used this little z-bracket, got the guy to make me one. It's really easy to use and get a nice light touch on the wheel. There are more out there, so there might be some feedback on that. I would say it can touch lighter than the screw on the X01 or X02 because on those, you can't see the spinner, and the screw puts it into the wheel faster than you can by hand. You can also see that the spinner is spinning, where in the X01 you don't know that for sure. Here's a question, how can you use the $1700 Blackstone thing on a table with a non-magnetic table? You'll have to push it by hand, just like you would the z-bracket.

Check this out, it came from the link below, post #20 looks like someone came up with a nice idea, looks like it'll cost not much more than the spinners and can be used with any tabletop holder. check out link #20 "The spinner holder is clamped in the skate holder and has the same thickness as a skate blade. Can hold up to 7 spinners and the spinner centers are exactly (or within a couple thousandths) of the skate blade center, so all you have to do is touch the spinner to the wheel, remove, insert skate, and sharpen. Nice thing is it will work with any existing tabletop system, any height holder, maybe even a dupliskate. Has worked fine."