Blackstone Flat-Bottom V Thread

[dogey 0]

two questions, what are the 80/1 and 85/1 FBV's for? goalies?

What's an FBV in between 100/50 and 90/75. I'm looking for slightly less sharp than the 100/50.

[rachael7 1]

...

What's an FBV in between 100/50 and 90/75. I'm looking for slightly less sharp than the 100/50.

There's a 95/75 that is a good compromise between the two.

[Blade-Tek 1]

Blademaster continues to disappoint:

1) Form dressing is as old as dirt, and Blademaster should have delivered this disruptive technology before Blackstone.

2) Blademaster's "The truth sheet Flat Bottom" is defensive, petty, and unprofessional. They could have demonstrated the advantages of their method but instead wrote a poorly constructed mess that makes one question their credibility. Talking about the potential for "no edge" on FBV, and then admitting the true width of a 90/75 flat bottom is actually 70 thousandths doesn't wash. Moreover, does anyone believe Blademaster used a "representative" Blackstone diamond roll in the numbers they published? While Blademaster may have a better method, I don't trust Blademaster now.

3) Blademaster's BFD isn't available on portables, and for tabletops, it's a Rube Goldberg device if I ever saw one (check out the YouTube video for a good laugh).

While I'm a Blademaster portable owner and Maximum Edge (Bob Allen) fan, Blademaster should be a Harvard Business Review case describing how not to address disruptive technology and the response to a competitor's actions.

I'll enjoy using my Blackstone FBV convertible spinner on my Blademaster portable.

Actually there was some credibility to their document, although I can't locate it anymore, they must have pulled it. When the BS first arrived I ordered up a small handful of spinners and after reading the BM sheet, I thought what the hell and since I had an in at a military technical unit, I had the spinners measured up with their laser equipment. . . . the BM document was pretty well on. . . the BS spinners were no where near their aclaimed tolerances. . . let's face it, they claim in one document to have 100/50 & 100/75 etc. . the 100 being thousands of an inch wide and the 50 or 75 being in 10 millions (their website)of an inch deep, their tech sheet claims the 75 or 50 is in one hundred thousands.

Give me a break! Unless you did as I did and have them measured up with laser technology, you will not know. I'm afraid your standard micrometer isnt going to cut it here! According to the military the spinners were plus/minus 25% Thats right TWENTY-FIVE % !! {largest tollerances found were in the depth}

I have the spinners and use them when clients are eager for an FBV, but with the blade thickness differences, it is a real pain in the a$$ to set up each different pair to ensure centering on a spinner with a +/- 25% tolerance. I offer it to clients only if they insist. . .and caution that it is not near as accurate as acclaimed.

These are the facts. I know it is the popular thing these days. People can be readily sold on almost anything. . . . I mean look at Bauer selling people the crap metal in their Lightspeed Pro holders...... some of those are like grinding plexiglass !

Edited January 9, 2011 by Blade-Tek

[Jordan 13]

Look...as long as there is a consistent grind from the 90/75 spinner when it dresses the wheel, and I like the resulting sharpening, why should I care if it is off by a thousandth or two?

Further, if there is enough separation between the various spinners, such that I can get my skates sharpened sharper, or less sharp. again what does your claim about accuracey matter?

Finally, I am going to bet that your quoted ROH of say 3/8" isn't any more accurate than Blackstone's claims. why don't you "laswer measure" that?

In the end, the FBV works, and I will continue to use it.

[jimmy 194]

Look...as long as there is a consistent grind from the 90/75 spinner when it dresses the wheel, and I like the resulting sharpening, why should I care if it is off by a thousandth or two?

Further, if there is enough separation between the various spinners, such that I can get my skates sharpened sharper, or less sharp. again what does your claim about accuracey matter?

Finally, I am going to bet that your quoted ROH of say 3/8" isn't any more accurate than Blackstone's claims. why don't you "laswer measure" that?

In the end, the FBV works, and I will continue to use it.

You are exactly correct on both counts. If I've been skating on say 1/2" and I switch to 100/50 and like it a lot more, well, discussion over. SO many have done this switch that any questions about the FBV's function and popularity can now be laughed off.

And I can guaranty that on ANY skate sharpening machine, when one factors in the slop in motor bearings, the drive shaft, the diamond arm, the diamond, the wheel, etc, the dressing of a regular hollow is not going to be exactly perfect each time either. It will be close that no one can tell the difference when skating, but still out of tolerances. We are not talking space program here, a tiny bit off tolerance is not going to be noticed by a skater. A sharpening by someone who doesn't know how to adjust for blade thickness, well that's a whole different story. Still, considering that most runners are now so close to 2.9mm, it's not very hard to adjust holder for a 1mm difference. Unlike the old days when CCM runners were 2.6mm and Tukk+'s 3.1mm and a lot of adjustment was required.

[goaliemanshark 6]

Oh man, I switched from 90/75 to 90/50. What a difference. I felt like i was skating on rails. Not sure i like it yet, gonna make the final decision tonight.

Interesting chart.

I always thought that is was #/50 but apparently to be more accurate it #/05. Also i was told that 90/75 was the 5/8 equivalent. Apparently its not... Interesting!

With all these choices and 10 dollars a sharpening how are you supposed to figure out which hollow you like?

[JR Boucicaut 3759]

.50, which is 50.

Same diference.

[dogey 0]

Oh man, I switched from 90/75 to 90/50. What a difference. I felt like i was skating on rails. Not sure i like it yet, gonna make the final decision tonight.

With all these choices and 10 dollars a sharpening how are you supposed to figure out which hollow you like?

The problem is that these spinners are not very consistent, at least not with the 90/75's

I have some data that I can post soon that the 90/75's are not what they should be. I have equipment that can measure to 1/1000 of a micron, but I'll wait to post a full comparison.

They should be sharper than 90/50's, but not if they're really more like 100/25's. Maybe it's a bad batch, I hope not all spinners are so inconsistent.

Edited January 10, 2011 by dogey

[goaliemanshark 6]

No thats not the problem, it cant be. Because the 90/75 sharpenings i have had for the last 10 months have all felt basically the same. At least to me. But when i changed it a drastic difference.

I dont think many skaters notice the inconsistency, there has to be some. But does it really matter? Maybe its your sharpening job?

[rachael7 1]

I'm looking forward to seeing both the methodology and results of these alleged tests, although somehow I doubt they are forthcoming. They sound like bunk to me and I find these posts suspicious, quite frankly. In order to actually measure the spinner in a useful way, it would have to be spinning, like it is in use - the relevant shape is not what is measured at any one point on the circumference, but the cumulative effect of the entire thing. The equipment to measure that does of course exist, but it is certainly not at all common, nor is it the most effective way to test the spinner. If it were my lab, we'd measure the shape that resulted from using the spinner, which would be a meaningful and repeatable test, rather than trying to measure the spinner itself, which would be extremely difficult and of very limited value.

[chiefs17 2]

When I first bought my X01, I was struggling with getting consistent results so I was checking out everything on the machine, including the spinners. I measured the spinners using an optical comparator, and found that they were way off from what they were stated to be. I also know that they vary a lot from the mini spinners used on X series machines, to the full size spinners used on shop machines, so it's not always easy to get consistency from machine to machine. This is disconcerting, but not the end of the world.

I think jimmy said it best. They may not be the correct measurement from what BS says they are, but they provide a good edge that is preferable in most cases to a traditional ROH. I'm fine with the fact that they can't get the exact measurements that they publish the spinners to be, but I would like the spinners to be consistent, so when I order a new one it will feel just like my old one, and if I have 2 different spinners they should be relative to each other. That's to be determined. I would like to see the results from this study.

Rachael7, you are correct. Measuring the shape of the dressed wheel would be the better way to get an accurate measurement. Then again, why not just sharpen a blade and measure that profile. That's the real result we're looking for anyway!

[goaliemanshark 6]

Wouldn't measuring the shape of the steel be the only thing that matters?

[rachael7 1]

Wouldn't measuring the shape of the steel be the only thing that matters?

Yes, and also the only thing that could be measured reliably. Due to the textured surface and irregularities associated with a spinning object, measuring the spinner is largely irrelevant, imo, and measuring the wheel is only slightly better. The finished result is the only thing worth measuring here, but you would have to use a different holder arrangement for testing purposes so that the human elements and deformation of the felt were accounted for. Measuring one spinner compared to another is of some use in assessing manufacturing consistency, but only if you can measure it while spinning. As I said before, even with a high power optical comparator (maybe 100x - 150x magnification) you're only looking at one point on the spinner, which would tell you very little about the actual profile it would apply to the wheel.

[dogey 0]

Ha, alleged results, okay, whatever.

Who said anything about measuring the spinner itself, all that matters is the cross-section put on a piece of steel, and that's easy enough to measure with appropriate equipment. I will do a comparison between BFD and FBV and traditional hollow, and it will be unbiased information.

Not sure why you would need to take the human element out of the test, most sharpening is done by humans.

[rachael7 1]

Ha, alleged results, okay, whatever.

Who said anything about measuring the spinner itself, all that matters is the cross-section put on a piece of steel, and that's easy enough to measure with appropriate equipment. I will do a comparison between BFD and FBV and traditional hollow, and it will be unbiased information.

Not sure why you would need to take the human element out of the test, most sharpening is done by humans.

Because the goal isn't to test the human. I could care less if you or the guy who does your skates has a good hand. We're talking about the equipment. And if that isn't obvious to you, then you probably don't have the necessary experience in performing controlled experiments to get any meaningful results.

[jagged 0]

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?

Edited January 12, 2011 by jagged

[JR Boucicaut 3759]

So is she.

[zebra_steve 11]

So how about a layman's solution.... pull the felt off and readjust the clamp back to center... no compression to deal with - at least from the felt....

The real issue with the inconsistencies would be going from one spinner to another (same size old to new), or one shop to another (if the spinners are on opposite ends of the tolerance)..... Same shop and same spinner then no big deal until they replace the spinner....

When I tried the FBV, I liked it enough to research the cost to retrofit my ROH sharpener with a magnetic base spinner ..... For now, I'm staying with ROH for economic reasons.... IMHO - I see the biggest issue with the spinner vs the ROH dressing diamond is that I only spend $25 on a new diamond vs $85 per spinner and I can adjust for the full range of hollows I want with one ROH diamond. To do the same with FBV I need to drop $85 per spinner and if the tolerance claim is to be believed I might get two differently labeled spinners that are nearly identical?

Edited January 12, 2011 by zebra_steve

[rachael7 1]

You're on the right track, Steve, but as was correctly noted, there are other factors, including vibration, that make the test considerably more complicated. Yes, all those factors do matter in the final outcome, of course, and controlling for them is not to suggest that they don't affect real world results. But the point is that we're talking about measuring variation in the spinners (which is what was claimed to be an issue), not variation in the operator, the stones or the machine. So if we want to test the spinners by making a grind with them, that grind would have to be absolutely consistent from pass to pass to make the results of any use in assessing the QC and relative tolerances of the spinners. Something similar to a Cag One type setup, where it is totally done by machine in a rigid fixture would give a reasonable chance at determining the actual variation in the spinners, which was what was originally being discussed. And even in a well controlled test setup of that type, with this many possible variables, you would need to take a statistically significant number of samples with each spinner (something on the order of 30 blades or so with each spinner) to get any kind of meaningful results.

One can throw about fancy terms like six-sigma that few here understand (I do, for the record), but when you're making claims of 25% variation from unit to unit, you're going to have to back that up with some reasonable sort of QC setup and test protocol if you want to be believed. Or at least some actual data for cryin' out loud. It is an entirely academic discussion anyway, since LOTS of people are using and liking the FBV spinner, and have no problem discerning a meaningful difference in performance through the different profiles. There is also a noticeable lack of complaints from people saying things like "I got a 100/50 at one place and it was nothing like the 100/50 I got at this other place." If there were a body of complaints to that effect, then this discussion would be relevant and something other than mere mental masturbation. But in the absence of such complaints in any significant number, it makes me question the motives of the people claiming (once again, with no data to back it up) that there is some massive problem with Blackstone's QC or technology.... especially when both of the posters making these comments are very low post count ids with no real rep here. Smells like sock-puppetry to me.

[Chadd 916]

...especially when both of the posters making these comments are very low post count ids with no real rep here. Smells like sock-puppetry to me.

What I've noticed is that the biggest critics always seem to have a financial incentive for attempting to discredit a product. In the case of the FBV it has often been that they are invested in another product and want to downplay the improvements of the FBV.

[MLSman 22]

If there were a body of complaints to that effect, then this discussion would be relevant and something other than mere mental masturbation.

What's wrong with mental masturbation? :)

Sorry...I couldn't resist! But I agree with totally...simply put FBV works and is a major improvement over ROH.

[rachael7 1]

Mental masturbation is a perfectly natural thing and nothing to be ashamed of. Just don't tell that to the attorney general :-P

[jimmy 194]

This topic has really degraded. We don't need engineers, we don't need to do testing. There are so many variables, it cannot be debated accurately on a board. FWIW, I personally have done over 45,000 FBV sharpenings in the last 3 years. Is that a good sample size? Please, tell me if that is not enough to verify accuracy of spinners? I calibrate my machines daily, making a mold from a sharpened blade, (each spinner tested) then view the mold with a microscope to see actual results. I use and go through a LOT of spinners each month and have not seen ANY variation in results. So much for this "major Problem" with spinners. Next topic please.

[zebra_steve 11]

This topic has really degraded. We don't need engineers, we don't need to do testing. There are so many variables, it cannot be debated accurately on a board. FWIW, I personally have done over 45,000 FBV sharpenings in the last 3 years. Is that a good sample size? Please, tell me if that is not enough to verify accuracy of spinners? I calibrate my machines daily, making a mold from a sharpened blade, (each spinner tested) then view the mold with a microscope to see actual results. I use and go through a LOT of spinners each month and have not seen ANY variation in results. So much for this "major Problem" with spinners. Next topic please.

Ummmm Jimmy ...... I gotta play devils' advocate here and ask you if you are really saying that you sharpened ~41 pairs of skates every day for three years? Not saying that that volume is not possible or unusual 'cuz I've been there on an occasion or two, but that's one heck of a volume in my mind. If you do a pair every 6 minutes then you have 4 hours of grinding every day - for 3 years..... Thinking about it makes my back hurt!

Rachael,

I HATE THE CAG ONE - but my experience with them was nearly two decades ago! Maybe they've improved since then. I was thinking more like a marriage between a wheel, a spinner, and a CNC machine.... The real hard part would be to isolate the blade and wheel without something like this.

Edited January 13, 2011 by zebra_steve

[rachael7 1]

The whole testing each spinner each morning, taking a mold of the resulting blade and examining it under a microscope thing is kinda odd too. Once or twice, why not I suppose, if you're dedicated. But every morning? Seriously? We're talking hockey skates here, not artificial heart valves.