A way to center a sharpening machine on the blade

[supersharp]

You will make great progress in a short period of time, since you already are in the mindset of improving how a tool works.  I hope you have some spare "disposable" blades--I really like having a nice stack of old blades on hand for practicing new ideas. Whenever skaters get new blades, I save the old blades.  Sometimes people donate skates to our club and the blades are too worn to be useful for a skater, so I also keep those.  I started with one pair of patch blades that were donated by the tech who trained me, which I was grateful to have but they weren't ideal since the toe pick is very flat on patch blades.  Now I have some unknown amount of blades, more than 25 pairs... now that I have a cross-grinder, it has been very nice to have the old blades to practice using the cross-grinder. 

Sharpening can be very stressful, but when it starts working, it is very satisfying to produce a good end product. 

[AlbaNY]

Some very good skate techs seem to do pretty well without taking any obvious measurements. E.g., they can judge edge evenness by sighting along the bottom of the blade, as it sounds like yours does. I have advocated taking measurements, partly because I think it speeds up the learning process. Most of the time, I don't measure either - just once in a while I recheck the profile.

There is a special blade holder that forces figure skating blades to not be warped, and there are also special holders for certain types of figure blades that won't fit in normal holders (including some figure skate blade holders), but for the most part, I think hockey sharpening machines - as long as they aren't automatic - can sharpen figure skates.

I would be horrified if they use a sharpening machine that automatically creates a "standard" hockey profile. For example, if it removes or trims toe picks or rounds off the back, or if it causes the blade to have relatively flat rocker (longwise curvature) in the center, but to have much more curvature at the ends.

If almost all the figure skaters in your country go to the same skate tech, maybe they have given that skate tech a fair amount of feedback, or if the skate tech is conscientious, they may have taken the time to learn about figure blades, so it is possible they might do pretty well.

And a lot of the same principles apply.

It is true that hockey skate techs usually remove more metal - but a conscientious hockey-trained tech who has also read up or studied or received feedback on figure skates might not do that on figure skates. I would guess that if you get about 30 or more sharpenings out of a blade pair (calculated by assuming each sharpening removes about .003", and the relationship to the toe pick remains fairly good for the first .1" or so of metal removed (people disagree on those exact numbers)), they are doing about right in terms of amount of metal removed.

When hockey trained techs try to restore or modify blade shapes, they typically seek a shape appropriate to hockey - typically one shape for offensive players, one for defensive players, and goalies need their own shapes - but, again, a conscientious well trained skate tech might know better than to do that on figure skates.

So I don't think we should casually assumed that the person does a bad job, just because they take no obvious measurements, and they don't have a machine specific to figure skates.

Also, I don't know whether either a Pro-Filer or a Berghman sharpener will work with your specific blades. tstop4me has pointed out that my casual assumption that you can make them work with all modern figure blades (mine are out of date) may not be true, for several reasons.

E.g., Pro-Filers are specific to one specific ROH (radius of hollow), and they were available for more than one blade width (e.g., hockey blades are thinner than figure blades) - and the hockey Pro-Filer kits had less stuff. I wasted a lot of time making a hockey Pro-Filer work on my figure blades. I widened the slot size, and reduce the depth of the slot, using a file, while keeping the slot centered on the stone. If you are a little afraid to use tools, that might seem scary. The Berghmans were only available for 1/2" hollow, the stones that came with them were of an older crumbly type, and were pretty coarse, and I don't know if they will work with all modern blades either - the slot width is adjustable, but the depth is not. (OTOH, the old used Berghmans are fairly cheap.)

(BTW I use " as an abbreviation for "inch", which is 2.54 cm in my country. E.g., 1/2"=1.27 cm. Do most people in your country know what inches are, and do they know about the " abbreviation?)

As a good starting point, you are right -  if you can scan in the shape of your blades (you may not need a mechanical pencil. If you are careful, and don't scratch the glass on your scanner, you can gently place a blades on the scanner , and just put white paper behind them, and get a good scan, without using a pencil - regardless, you should also place rulers on the same scan, so we can figure out the scaling, or put graph paper with a known spacing behind them), and someone else here happens to have the same blade style, you can check the shape. If the blade shapes are pretty close, that would be a good indicator that your skate tech might know what they are doing. Do it for both blades.

Query, I am sorry I totally missed that there were new replies here until now. 
I never thought about scanning the blades, but that's a great idea if my husband will not mind.  I have a transparent pattern drafting ruler with a grid and inches (and I think maybe also cm?) on it that I can include. 

I doubt I could find either of those two sharpeners here, but I expect that as you say, the sharpening guy must have taken a lot of time and included plenty of feedback.  It's just a bit wild to see how he does it! 

I used metric most and learnt it in school (in the US) but had to finally get used to inches when studying at FIT.  I'm quite good at recognising or marking exact inch based measurements by eye since then.     I don't think many people here have much experience with inches, and now I am curious if they use the same terms for radius of hollow fractions or what?? 

[Query]

I used metric most and learnt it in school (in the US) but had to finally get used to inches when studying at FIT.  I'm quite good at recognizing or marking exact inch based measurements by eye since then.     I don't think many people here have much experience with inches, and now I am curious if they use the same terms for radius of hollow fractions or what??

I was taught in school that it was illegal to use inches and other old imperial units in most countries.

But I eventually realized that couldn't be completely true.

[AlbaNY]

I was taught in school that it was illegal to use inches and other old imperial units in most countries.

But I eventually realized that couldn't be completely true.

Illegal?! 
My (American) school system promoted the use of metric, which I thought was pretty cool, except some imperial for some things in shop class and definitely home ec. 
I notice that Canada seems to mix metric and imperial somewhat.  Then there is the UK with stone for weight too. 
I always preferred metric except for temperature.

[Query]

AFAIK, everyone or almost everyone measure skate ROH (Radius of Hollow) and Rocker radius in fractional inches and feet. E.G., MK and JW specified their blades that way (though they no longer specify or pre-grind ROH for high level blades), even though they are located in Sheffield, UK. And, at least on the sharpening machines with dressing systems that I personally have seen, the scales were marked in fractional inches. But I think I once saw someone specify Rocker radius in metric units, so maybe I'm wrong.

That said, there are extremely good reasons for people to use metric - not just trivial one of making it easier to use base 10 arithmetic. A bigger problem with inches, feet, statutory miles, nautical miles, ounces, pounds, tons, and the square and cube equivalents, is that they have had many somewhat different definitions, at different times, as well as in different countries.

E.g., one Scandinavian country currently defines 10 inches per foot, but AFAIK all others use 12 inches per foot. The U.S.A. alone has used at least 3 different definitions of inch, foot, and statutory mile, and still uses two. (Those two only differ by 2 parts per million - the current U.S. legal inch, which the USGS called the international inch is 2.54 cm; but many map makers, including the USGS, and most but not all US state survey offices, and AFAIK all nominal runway lengths, still use an older standard, that the USGS called the "ground survey inch, 1/39.37 m. Congress created a special "temporary" exception for the USGS, so they didn't have to redraw all their maps, and the USGS tried hard to convince other U.S. mapmakers to follow them, and to make "temporary" permanent.) Various countries also still define the nautical mile - which was originally intended to be the approximate average size of a minute of latitude in the ocean near Germany - in different ways. These sorts of things matter significantly if you use large scale gridded maps, especially UTM maps.

Wooden boards are often measured approximately before kiln drying, and so are substantially smaller than the nominal sizes at the store. Plywood and particle board are always made smaller in the first place. I'm not sure if that is true in countries that use metric units. E.g., do metric countries still use "2x4s"?

Likewise for square and cubic units of area and volume, as well as acres. And we in the U.S. sometimes use other units for volume, like teaspoon, tablespoon, pinch, bushel, peck, etc.

The U.S.A. still uses at least two definitions of ounce and pound" - avoirdupois for most things, troy for precious metals. We mostly use carets for precious stones.

Even degrees, minutes and seconds of angle, when it comes to latitude and longitude can be very complicated, as there are many different ways of measuring them (in public school I was taught about geocentric latitude and longitude; I learned later that geodetic and astronomical coordinates are more common), as well as different estimated sets of reference points (e.g., points on the earth, and the earth's center, and different era nominal poles and equator) that have differently defined values, and between which other values are interpolated. It's enough for a poor navigator to run aground, be arrested, have their ship confiscated, or be tortured to death as a spy, if they fish or in some cases just enter the wrong national waters or territories. Remember the U.S. spy plane that China forced down a while ago, and the U.S. hikers that Iran arrested and imprisoned (maybe worse) as spies? I wouldn't be surprised if they inappropriate used a U.S. market GPS set to one or another version of WGS 84 latitude and longitude with maps that were drawn in some other coordinate system. You could easily run aground if you use NOAH nautical charts (which are all old, out of date, and in many cases no longer meet the U.S. must-carry provisions) with a GPS that uses WGS 84.

(Unfortunately, there are no metric systems for latitude and longitude, and even metric unit altitudes can have different meanings depending on origin baseline and projection direction. And reference points are revised by a committee after major geological activity, and/or big asteroid impacts. So they will remain messed up.)

Horsepower too - last I knew UK uses 550 ft-pounds/minute; USA uses 746 watts, both of which are far less than a horse, or even a fit person, can generate in the short term. Except - marine engines are measured very inconsistently, often differing from true used or effective power by orders of magnitude. Some marine motor makers even use propeller force while standing still to measure power. If the ratings were actually correct, many marine motors could be connected to a generator to create much more power than they used, which would be very useful.

Metric units are so much better. They have changed much less over time, and AFAIK are the same in all countries.

E.g., shoe and boot (including skate boot!) sizes differ country to country, manufacturer to manufacturer, sometimes even model to model, as well as by age and gender groups - but are much closer to be standardized for those who measure in metric mm. (Of course assumed foot shapes and bottom tilts are still different.)

[Qsior]

Hello all ,

For 3 years, I sharpening skates on a blademaster machine, I thought I knew something, but after reading Yours texts, I think that I still need to learn.

I have a sp850 blademaster and 3 holders including a sh6000. if when the blade edges are even my holder is set well?
can it be slightly tilted and still have straight edges?

[marc]

bonjour Qsuior,
content de savoir que d'autres affute avec blademaster 850.
je fais avec le sh 2000 et il est nul par rapport au sh6000 et de ce fait je l'ai modifié moi même, pour qu'il ressemble au sh6000.
vu qu'on est à peu près pareil, j'essaie demain de te faire quelque photo de tout mes réglage pour essayer de centrer au mieux.
je m'aide d'un comparateur, de niveau à bulle, stylo noir...
j'ai aussi une équerre de précision que kaitsu m'a recommandé.
Comme je lis  tout, regarde et relis les post de Kaitsu, et il montre bien avec des photos comment centrer au mieux.
Tu as certainement compris qu'on avait une meule trop grande, mais je ferais  tout pour essayer de me rapprocher du travail des petites meules.
Et toi de puis 3 ans, les patineurs(free skate and no hockey)) sont contents de ton affutage?

[marc]

oh, excuse me....
Hello Qsuior,
glad to know that others sharpen with blademaster 850.
I do with the sh 2000 and it sucks compared to the sh6000 and therefore I modified it myself, so that it looks like the sh6000.
since we're pretty much the same, tomorrow I'll try to take some pictures of all my settings to try to center them as well as possible.
I use a comparator, spirit level, black pen...
I also have a precision square that Kaitsu recommended to me.
As I read everything, watch and reread Kaitsu's post, and he shows well with pictures how to center the best.
You have certainly understood that we had a wheel that was too big, but I would do everything to try to get closer to the work of the small wheels.
And you for 3 years, the skaters (free skate and no hockey)) are happy with your sharpening?

[Qsior]

And you for 3 years, the skaters (free skate and no hockey)) are happy with your sharpening?

I think yes, slowly in my city they say that I ma good, but I know that I have a lot to learn, especially in professional blades.

  I would like to buy a machine with a 3 inch wheel but it's hard to choose, I know IE is the best but maybe in my case (I have 3 BM holders), Blademster would be better?

I even made the Matrix and Paramount holder myself ;-)

And a few years ago my daughter also skates in club like Your :-)

[Kaitsu]

if when the blade edges are even my holder is set well?
can it be slightly tilted and still have straight edges?

I am not sure if I did understand you question correctly. I think most of the skate holders are not parallel to the wheel (tilted like you said). Risk to this is higher on table top machines which skate holders does have 3 adjustment knobs. Maybe some table top machine users can comment how they normally adjust their skate holder height. Do you mostly use just two knobs which are more close to wheel or all three. And when you have adjusted them, will you ensure after every skate that holder is adjusted back to square? Most likely not.

I think small parallelism error (tilting) in skate holder is not an issue as long as you measure and ensure that edges are even after your sharpening.

But if the question was, can you sharpen all skates with same setup if you have ones adjusted your skate holder, answer is: No, you cannot.

I made very quick sketch to explain one reason to my opinion. If you skate holder is not parallel to the grinding wheel, your blade height changes depending how you position the skate in to your skate holder. You can probably demonstrate this with simple test. Sharpen some blade, remove it from skate holder and paint the blade with the marker. Put it back to skate holder slightly differently than in previous time and make very gentle grinding pass. Most likely you will see that wheel is contacting differently than in previous time even the blade is same.

[Bill_S]

The tilt of the skate blade while grinding is not critical because the holder can be adjusted to get level edges even when the blade is tilted. This drawing shows two scenarios, both of which provide level edges...



If you raise or lower the skate holder vertically with either of these two cases, you no longer have level edges.

As Kaitsu states, it is not realistic to set the holder for one set of blades and expect it to work with other blades. Blade thicknesses vary, and some blades have separate, thick support stanchions. You must test with each blade.

I have a skate holder with three height adjusters. Frankly, the adjustments are small enough with any blade that I now use the front two adjusters only. I have been ignoring the rear adjustment after having initially set the overall height. If I get a blade with a thick stanchion (i.e. Matrix, Paramount, etc.), I will have to adjust the rear too.

[Qsior]

Kaitsu, Thank You for Your reply

Yes I have skate holder with 3 knobs .
Yes of course normally I use only 2 and check the edges , different skates different settings
But when I bought that skate holder I made adjustment for my machine.

Your sketch is perfect , that is what I think .
And if I have something like that is it bery bad? even though the edges are squere ?
As You wrote that ,, small parallelism error (tilting) in skate holder is not an issue as long as you measure and ensure that edges are even after your sharpening. "

[Qsior]

The tilt of the skate blade while grinding is not critical because the holder can be adjusted to get level edges even when the blade is tilted. This drawing shows two scenarios, both of which provide level edges...



If you raise or lower the skate holder vertically with either of these two cases, you no longer have level edges.

As Kaitsu states, it is not realistic to set the holder for one set of blades and expect it to work with other blades. Blade thicknesses vary, and some blades have separate, thick support stanchions. You must test with each blade.

I have a skate holder with three height adjusters. Frankly, the adjustments are small enough with any blade that I now use the front two adjusters only. I have been ignoring the rear adjustment after having initially set the overall height to contact the center of the grinding wheel. If I get a blade with a thick stanchion (i.e. Matrix, Paramount, etc.), I will have to adjust the rear too.

It is great info , thank You 

[AlbaNY]

I'm not sure scanning worked well enough.

[Kaitsu]

At least for me these pictures won't tell so much when most interesting part of the blade is missing. Your picture would be more useful if the blade would be rotated 90 degrees so that we can see the blade from the longer distance. It is also a bit unclear if you have tried to use some pencil to trace the profile. Take photos from your blade so that we can see about 1/3 of the blade and so that we can see also at least lowest toe pick.

If the whole profile should be somehow evaluated, you can also trace the whole profile to the paper with the thinnest pencil what you can find. Scan that paper and let us know the distance from the tip of lowest toe pick to the end of tail so that I can get the scale from that.

[AlbaNY]

I was afraid it did not show much properly.  I already had another sharpening today, and we did another set of scans for the profile.  I hoped showing from the toe pick area would be the most important information.  For some reason I thought the picks were in the images, but I see now that they are indeed not.  I could not get the blade on the scanner flat except on the short side, and I held it in a way that I thought the pick was there.  Ugh.  I was going to try the pencil tracing, but its too late now for comparing sharpening. 

If I move back here then I'll have plenty of opportunity to check on all this again.  I can try to do better to compare with someone else's or a new Aspire blade now.

Does anyone have any idea about metric RoH?  The sharpener asked if I was happy with what I had, and when I asked what it was the answer did not make sense at all since it was not the usual inch fractions.
I can't try the coin trick to tell until I am back in the US.

[Bill_S]

The scans are a bit low in resolution as well as not showing the entire blade. Like you concluded, you'd be better off tracing with a sharp pencil.

However, I took a few minutes to graphically compare your existing scan with a pencil tracing of a new MK Pro (10-1/4") blade. In Photoshop, I did some "freehand" overlays to see if I could find any glaring issues. I'm comparing your Aspire with an MK Pro,  which complicates things too.

Here's the graphical comparison. You'll have to click the image to see it larger.



At this scale, I don't see any irregularities. There could still be some, but it's not enough to discern with the available information.

[Kaitsu]

Does anyone have any idea about metric RoH?

Does attached file help?

[AlbaNY]

Wow, thank you for doing that Bill.  I have practically no computer skills and do everything analog.  (My graduating class was the last one to only do flats & specs and design by hand rather than to learn Photoshop or Illustrator, and I'm pretty old school anyway so I never tried to learn it much.     I definitely would have done better with a pencil in retrospect.)  I'm pretty annoyed that I didn't catch that the picks were not in the image, but I guess I can get a pencil tomorrow and trace what I have now.

I'm pretty impressed at how well those match.  My blades are 9 3/4" in case I did not mention that before.  Eventually I'll compare at my favourite skate shop, but it'll be a while. 

Kaitsu, thank you for finding that.  I will see if I can figure something out.  What I thought he said was "18.12" which I couldn't make sense of.  If I can get my husband to call , as the guy asked, after I try skating with the sharpening then I will have him ask and find out for sure, but sometimes he gets too annoyed to act as my translator, so I don't know if it'll happen. 

[Query]

Does anyone have any idea about metric RoH?

Are you saying that your sharpener is calibrated in metric ROH sizes? If so, I didn't know any were like that.

If it is, can you tell me again the type of sharpening machine being used?

BTW, if you look up "radius gauge" on eBay, you will find devices which can measure the radius of hollow. You touch the tool to the middle of the hollow (not the edges, which get worn down), and see how it fits. If there is a gap between the hollow and the tool in the  middle, use a smaller radius. If there is a gap at the ends, but not in the middle, use a larger radius. You may need a magnifying glass, if you don't see too well up close, because the gaps are very small.

E.g., https://www.ebay.com/itm/154337128322?hash=item23ef35af82:g:y5oAAOSwsvlh3N0X is calibrated in metric, in about the right range.

And https://www.ebay.com/itm/151318272519?hash=item233b459a07:g:NOsAAOxybqpRhv6d is calibrated in inches, though the highest is 1/2".

BTW, you can convert inches to mm by multiplying by 25.4. E.g., 7/16*25.4 inch (abbreviated 7/16") is 7/16*25.4=11.1125. But Katisu did the work for you - "R" is radius in his chart.

[AlbaNY]

I'm sorry that I am not more knowledgable, Query. 

Regarding the machine I am attaching a photo, and that's the best I can do. 
I'd like to get a gauge.  I tried using Euro coins but could not decide if 20 cent was right or not.  I think it may be?  The 2 cent (which has distracting scallops on the edge) looked pretty close also, so I don't particularly trust my eyes on the matter.    

[tstop4me]

Regarding the machine I am attaching a photo, and that's the best I can do. 

Good grief.  That looks like a standard bench grinder.  And he's just holding and guiding your skates entirely by hand.  Is he the sharpener that your coach uses?

[Bill_S]

That's what she described earlier, and it boggled my mind then. I'm still boggled.

If there was a registration stop on the unseen side of the wheel against which the flat of the blade rides, I could almost see it in capable hands. But I fear that it's purely freehand.
Try drawing a straight line without using a ruler, and you get an idea of the difficulty.

Try giving THAT grinder to the average kid at the pro-shop!

[tstop4me]

I'd like to get a gauge.  I tried using Euro coins but could not decide if 20 cent was right or not.  I think it may be?  The 2 cent (which has distracting scallops on the edge) looked pretty close also, so I don't particularly trust my eyes on the matter.   

Don't fret too much about this.  Even if you had a set of radius gauges instead of a set of coins, skill and practice would still be needed to get good results.  The main problem is that the thickness of a blade (distance between the inside and outside edges) is only about 0.16 inch/4 mm or less for a figure skate blade.  That means you're sampling only a minuscule arc of a circle.  Add to that, unless you have special jigs (which most skaters don't), you're holding the skate in one hand, the gauge in the other hand, and trying to keep both aligned and steady.  And, if you do need a magnifier, since you don't have three hands, you need a hands-free magnifier (e.g., attached to a stand or strapped to your head).  And, of course, there's the issue of proper lighting:  I find the gap between the gauge and hollow is more distinct if I shine a small light from the back of the gauge, but you don't want too bright and too large a lightspot.  So you've got a lot to play with ... just like skating.

[AlbaNY]

Good grief.  That looks like a standard bench grinder.  And he's just holding and guiding your skates entirely by hand.  Is he the sharpener that your coach uses?

My coach, who I trust very much and think is absolutely excellent (and who also competed in two Olympics, coached at an olympics, coached/trained at a famous training centre etc... he has plenty of experience...) recommended him.  I crossed paths with another coach having his skates sharpened one time too.   
It's pretty mind boggling, I agree.  That's why I am so interested in comparing my blades etc, but I have to admit that they feel entirely alright despite the method.  (Today I did have a heck of a time stopping which I always heard of but had not noticed post sharpening before, but the edges feel niiiiice.  Spinning went better today too.)