Question for blade sharpeners

[mintypoppet]

When I have my blades ground, I ask for them to be as sharp as possible, because I really hate skiddy blades and rarely have trouble stopping even on freshly ground blades. But while they are always sharp to start off with, they sometimes hold the grind and sometimes don't.

Twice recently, I have had my blades ground and they have started skidding within 3 weeks. They were not consecutive grinds, and the grind in between lasted for 8+ weeks (which is normal for me). They were all ground by a good sharpener, but he isn't local, so it requires some forward planning to get them done.

It has been suggested that a very sharp grind doesn't last as long. Do any of you blade-savvy people have a take on this, and what should I be asking the sharpener for to maximise the life of the grind?

[fsk8r]

When I have my blades ground, I ask for them to be as sharp as possible, because I really hate skiddy blades and rarely have trouble stopping even on freshly ground blades. But while they are always sharp to start off with, they sometimes hold the grind and sometimes don't.

Twice recently, I have had my blades ground and they have started skidding within 3 weeks. They were not consecutive grinds, and the grind in between lasted for 8+ weeks (which is normal for me). They were all ground by a good sharpener, but he isn't local, so it requires some forward planning to get them done.

It has been suggested that a very sharp grind doesn't last as long. Do any of you blade-savvy people have a take on this, and what should I be asking the sharpener for to maximise the life of the grind?

Some of the blade "stickiness" vs. "skiddiness" is down to the actual grind done on the blades. I think they normally do something like a Radius of Hollow of about 8/16" on figure skates. Sharper blades (more stickiness) are generally on a smaller ROH than this (say 7/16 or less) and skiddier blades are flatter than this (9/16 or more).

I had a grind done recently that whilst it started off sharp was dull in about two weeks which is unusual (I'm more an 8 weeker myself), I had them sharpened by someone different that time as it was urgent (I only had a couple of weeks between competitions and they should have been done before the first one) and later discovered that he'd put somewhere close to 12/16" on them. Once I had my regular grind done, I was happy again and they were holding their grind.

So whilst there's probably something in the very sharp blades not holding their sharpness that long, there's also something in the perception that the different radii give based on what you're used to.

So it might just be you've had a couple of dodgy grinds put on them by accident as most people are still doing grinds manually. I've recently discovered someone who has an automatic machine which takes out some of the human error and I like the consistency it gives.

[Kay]

The quality of a sharpen, based on technician skill and equipment will significantly affect the feel of your blades. The above post describes this more.

Also, in addition to sharpening, your habits can affect the sharpness of your blade. Both how often you skate and the hardness/temperature of the ice surface can affect this. Walking around without guards on will dull your blades faster than almost anything. While most people realize this, it is also important to clean your hard guards (walking guards) - a lot of the time, small dirt/debris can accumulate in your guards, so when you put them on your skates, you are still dulling them, as the grit essentially acts like sand paper.

Talking with your sharpener and taking immaculate care of your blades should help this. Good luck!!!

[Rusty Blades]

Conditions and personal preference are huge factors in when to sharpen. I am heavy, skate on hard ice, and prefer really good grip (on edges) so I sharpen often. I have also gone from 1/2" to 3/8" to 5/16" RoH over the years. I take VERY good care of my blades, seldom walk in hard guards, NEVER walk on bare blades (one step on rubber to where I take my skates off) and I resharpen about once every 6 to 8 weeks (10 to 15 hours of skating). Of course I sharpen my own so it isn't a problem.

The smaller RoH will NOT dull faster than a more shallow RoH - they will retain their grip far longer - but they are more easily damaged - it doesn't take much to put a nick in the edge. You will notice the wear sooner but your grip on the ice will actually last longer.

[mintypoppet]

The smaller RoH will NOT dull faster than a more shallow RoH - they will retain their grip far longer - but they are more easily damaged - it doesn't take much to put a nick in the edge. You will notice the wear sooner but your grip on the ice will actually last longer.

Thanks, that's useful to know. I should have stated that these are (MK) dance blades, and I have a 5/16 hollow on them (ie. the manufacturer's standard for these blades).

I rarely use hard guards, having been told off for using them by my sharpener. His view is that that walking on rubber matting is gentler on the blades - provided I watch where I'm walking and avoid bits of debris. I think that debate could open a real can of worms though! :lol:

[Skate@Delaware]

Thanks, that's useful to know. I should have stated that these are (MK) dance blades, and I have a 5/16 hollow on them (ie. the manufacturer's standard for these blades).

I rarely use hard guards, having been told off for using them by my sharpener. His view is that that walking on rubber matting is gentler on the blades - provided I watch where I'm walking and avoid bits of debris. I think that debate could open a real can of worms though! :lol:

I would rather walk on my hard guards-I know what debris is on them (none) vs. walk on the dirty rubber matting covered with dirt that you cannot see.....that will nick and dull down your blades (imagine walking on sandpaper).

Of course, put soakers on your blades once they are wiped down and placed into your skate bag. ;)

[Rusty Blades]

If you have to walk on rubber, try to stay up on your toe picks. The area right behind the pick isn't sharpened anyway.

[Query]

Sharpening wheels typically come in 3 grit grades - course, medium and fine. Typical sharpeners only use the course, because it's fast. A really good sharpener (and you may have to pay extra for a high end figure skating sharpening), uses all three, though if you have sharpened it quite recently, he/she may not need to use the course and/or medium grit wheel. The fine wheel produces a much keener edge, which feels sharper and stops sideways skid better.

That's not the worst thing they can do. I've known several people whose figure blades were effectively completely destroyed by being shaped the same way as hockey blades.

Use a consistent sharpener - not just the store, but the one person in the store who seems to do a good consistent job. That will lengthen the life anyway, because each wheel actually has a slightly different shape, so switching between sharpeners removes more metal. It's also important to make sure they use a consistent hollow, for the same reason. Ask around to see who the good skaters and coaches use.

A smaller hollow radius feels sharper, but wears down faster.

As many people here know, I hand sharpen. But what I do can also be done with machines, if the sharpener does a careful job using a fine grit grinding wheel.

Essentially, you get the sharpest results if you grind to create a horizontal lip or burr, then straighten it upwards (which becomes downwards when you skate) into a piece of sheet metal that extends into the ice. This is the way kitchen knives and razors are sharpened - which is why people can use steels and strops to straighten the edge, instead of re-sharpening it every time. Unfortunately, ice wears down the extension somewhat fast, but the result is worth it to me.

Many sharpeners do this by stroking a flat stone against the blade to straighten the edge. It lasts a little longer if the stroke bends the edges inwards a bit, as most do, though that feels slightly less sharp. (Other sharpeners de-burr to remove the lip or burr, making it much less sharp.)

The result is much much more effective at stopping sideways skid than if they do it the other way, creating a less effective bite into the ice by just using the grinding wheel to create an edge consisting of the intersection of the hollow grind curve with the edges of the blade.

But walking even a couple steps on rubber will largely destroy or horizontally re-flatten the extension, because it is very thin and fragile.

If you want a really sharp edge consistently, you can get it by doing your own sharpening. Some of us can only afford a hand sharpener - the Pro-Filer is the only one I know that does this job well enough by enforcing a consistently hollow shape, though even it is over-priced. If you do, I strongly suggest you turn the filer 180 degrees partly through the grind, so you get consistent edges on the inside and outside of the blade, and that you use the flat stone as indicated.

The Pro-filer does not come in 5/16. 3/8 produces slightly less bite, but if you do the extension thing I mentioned, hollow is relatively important, because the extension is mostly what stops the sideways motion, instead of the bite created the other way. It also wears away less metal, so the blade lasts longer.

But you can save yourself the trouble of buying and learning to use your own sharpening equipment if you can find a particular sharpener who does a good consistent job. Like I said, ask around.

[mintypoppet]

If you have to walk on rubber, try to stay up on your toe picks. The area right behind the pick isn't sharpened anyway.

Yes - I try to!

But you can save yourself the trouble of buying and learning to use your own sharpening equipment if you can find a particular sharpener who does a good consistent job. Like I said, ask around.

The thing is, that he *is* a good independent sharpener - they are expensive blades, and I wouldn't trust them to anyone else! He used to work for MK, and is recommended by just about everyone.

The same issue happened with my previous sharpener, who is also highly recommended and well-known, but is further away geographically. This is why I wondered whether I am asking for the wrong thing, and therefore getting the wrong result.

[Rusty Blades]

I don't want to start a scrap here but I really feel the need to comment on a few things based on decades of machineshop and metalworking experience.

The "horizontal lip or burr" created from grinding is usually referred to as a feather and it is thinner than paper. It is effective at cutting through flesh but is far to thin to support any weight and is the result of removing material too quickly with too coarse a wheel. It serves no purpose in skating and that is what is removed when a skate sharpener uses a hand stone. I use extra fine aluminium oxide wheels and light passes which leaves no feather at all.

[Query]

The "horizontal lip or burr" created from grinding is usually referred to as a feather... is far to thin to support any weight.. It serves no purpose in skating.

I think most sharpeners would agree with you. Sid Broadbent (iceskateology.com) does. He thinks it would slow the skate down.

But some of the best known here do use it the way I describe, and the instructions that currently come with the Pro-Filer are very explicit about how to create and use that lip.

I don't use it to support weight. I think it slices through the ice surface. Maybe it makes no sense. What I know is I love the way it feels. Probably lets me get away with improper blade alignment. A really good skater like you wouldn't need it. You could probably skate on an unmodified bone, old style.

Wish I had your machine shop experience. I don't know how to make much of anything, and can't find anyone who teaches adults. There's a public school that teaches seperate wood and metal shop classes to adults a few hours away in Virginia, but the classes are 9 months long.

Why do you need a course grind to create it? What process makes it happen?

[Rusty Blades]

I think most sharpeners would agree with you. Sid Broadbent (iceskateology.com) does.

LOL! How strange. I know Sid quite well and we discussed the science of sharpening and skating at some length.

Why do you need a course grind to create it? What process makes it happen?

I don't remember the exact physics but as you know, you can cut into metal with a hard toolbit and create a curl where the edge is torn away from the base material but still attached. This process also creates a great deal of heat. It seems to be the same with coarse grinding. With fine grinding, metal seems to be removed in such tiny pieces and it does not continue to adhere to the base metal. I know when I fine grind on my machine, even though the wheel has a surface speed of 106 feet per second (7" wheel at 3600 RPM) even after 4 or 5 passes the blade is still stone cold to the touch.