Query
02-10-2009, 11:38 AM
I wanted to decrease the rocker from 8' to 7' on my Jackson Ultima Matrix Dance runners, to make them more like the rather expensive MK Dance blades I had liked, without throwing away the 3 pair of MK Dance runners I now have. (I also have a pair of Supreme freestyle runners and a pair of Synchro runners. When they discontinued the interchangeable blade Matrix line, I bought all the runners I might ever want.) But that would ground away a LOT of metal, dropping lifetime, and force me to grind down the first toe pick a little too.
Then it occurred to me: What if I deliberately sharpened them to accent the sweet spot? That would less metal, maybe a couple hundredths of an inch - which meant I could easily put it back if I didn't like it, without losing much metal.
So I did.
It worked! As long as I spin, turn or twizzle right there, it is a lot easier. Feels like a completely different blade. Much easier to spin, turn or twizzle.
Maybe it makes sense to create a second sweet spot near the back, to make back three's easier... I don't test or compete, so I don't have to worry whether the skating organizations would consider a second sweet spot cheating. (Would they?)
Technical Stuff
A sweet spot along the blade is where there is a slightly convex angle between two different lengthwise (rocker direction) arcs, designed to make it easier to rotate there. AFAIK, all figure blades have one sweet spot, near where they think you will spin, turn and/or twizzle. Hockey blades have two, near the two ends, for much the same purpose.
Figure blade sweet spots are typically lost after a few sharpenings, unless the sharpener really knows what they are doing, and deliberately puts them back, because they are so subtle. Some skaters move their blade sweet spots to where they prefer to rotate. Hockey blade sweet spots are extreme, to allow fast turns, and probably never go away.
I'm not a pro, and am a klutz besides, so I use the Profiler hand sharpening kit, which contains one course and one fine cylindrical diamond dust sharpening stone, in holders that grasp the blade. I happen to like it very sharp, and have yet to find a shop with a machine sharpener that can get it as sharp. Besides, you waste maybe 5-10 times less metal at hand sharpening speeds. (At higher machine sharpening speeds, sharpening wheels grind away the blade to make an edge, rather than partly re-shaping it.)
I'm not sure the holders are needed - mostly they get in the way, so I have to remove the runners from the mounting bracket to fit them. I hate that, because the Matrix mount bolt metal is so soft, and the hex key that fits the heads so small, the key tends to strip the bolt, and I will eventually have to replace the bolts, or hammer in a slightly larger key or other screwdriver.
It comes with thin masking tape to make the fit tighter - which I used for this. The main purpose of the cyclindrical stones is to distort the metal in such a way as to create edges, though you still grind away some metal too.
It also has a flat fine sharpening stone, which you brush vertically from the direction of the mount towards and past the edge, at successive positions along the length of the blade, on both sides, to straighten the edges.
(Maybe there are cheaper brands of cyclindrical sharpening stone, in the right radii to match the hollow. I'd love to know of them.)
It normally takes 2 or 3 passes of the course grain cylinder, followed by a few passes of the fine grain cylinder, and a couple brushes at each point with the flat stone, to make blades really sharp, if the blade isn't too worn down.
So I used about 5 passes of the course cylinder, starting at the sweet spot, and increasing pressure as I moved towards the ends. I also taped the toe pick, so it wouldn't grind it off, and did the usual stuff with the fine cyclinder and the flat stone.
I use water as a sharpening lubricant on the stones, because it makes less of a mess in my bag than the included oil, and theoretically produces a cleaner edge.
(Using water is a traditional Japanese blade and tool sharpening model, which has recently become popular outside Japan.)
It was Easy. I think anyone familiar with hand sharpening methods could do it to their blades.
Then it occurred to me: What if I deliberately sharpened them to accent the sweet spot? That would less metal, maybe a couple hundredths of an inch - which meant I could easily put it back if I didn't like it, without losing much metal.
So I did.
It worked! As long as I spin, turn or twizzle right there, it is a lot easier. Feels like a completely different blade. Much easier to spin, turn or twizzle.
Maybe it makes sense to create a second sweet spot near the back, to make back three's easier... I don't test or compete, so I don't have to worry whether the skating organizations would consider a second sweet spot cheating. (Would they?)
Technical Stuff
A sweet spot along the blade is where there is a slightly convex angle between two different lengthwise (rocker direction) arcs, designed to make it easier to rotate there. AFAIK, all figure blades have one sweet spot, near where they think you will spin, turn and/or twizzle. Hockey blades have two, near the two ends, for much the same purpose.
Figure blade sweet spots are typically lost after a few sharpenings, unless the sharpener really knows what they are doing, and deliberately puts them back, because they are so subtle. Some skaters move their blade sweet spots to where they prefer to rotate. Hockey blade sweet spots are extreme, to allow fast turns, and probably never go away.
I'm not a pro, and am a klutz besides, so I use the Profiler hand sharpening kit, which contains one course and one fine cylindrical diamond dust sharpening stone, in holders that grasp the blade. I happen to like it very sharp, and have yet to find a shop with a machine sharpener that can get it as sharp. Besides, you waste maybe 5-10 times less metal at hand sharpening speeds. (At higher machine sharpening speeds, sharpening wheels grind away the blade to make an edge, rather than partly re-shaping it.)
I'm not sure the holders are needed - mostly they get in the way, so I have to remove the runners from the mounting bracket to fit them. I hate that, because the Matrix mount bolt metal is so soft, and the hex key that fits the heads so small, the key tends to strip the bolt, and I will eventually have to replace the bolts, or hammer in a slightly larger key or other screwdriver.
It comes with thin masking tape to make the fit tighter - which I used for this. The main purpose of the cyclindrical stones is to distort the metal in such a way as to create edges, though you still grind away some metal too.
It also has a flat fine sharpening stone, which you brush vertically from the direction of the mount towards and past the edge, at successive positions along the length of the blade, on both sides, to straighten the edges.
(Maybe there are cheaper brands of cyclindrical sharpening stone, in the right radii to match the hollow. I'd love to know of them.)
It normally takes 2 or 3 passes of the course grain cylinder, followed by a few passes of the fine grain cylinder, and a couple brushes at each point with the flat stone, to make blades really sharp, if the blade isn't too worn down.
So I used about 5 passes of the course cylinder, starting at the sweet spot, and increasing pressure as I moved towards the ends. I also taped the toe pick, so it wouldn't grind it off, and did the usual stuff with the fine cyclinder and the flat stone.
I use water as a sharpening lubricant on the stones, because it makes less of a mess in my bag than the included oil, and theoretically produces a cleaner edge.
(Using water is a traditional Japanese blade and tool sharpening model, which has recently become popular outside Japan.)
It was Easy. I think anyone familiar with hand sharpening methods could do it to their blades.