ISk8NYC you are completely correct. I quoted someone else:
>doubletoe said
>02-10-2009, 01:08 PM
>I would think if you created a second sweet spot near the back of the blade, it could make your jump >landings really rocky. For jumps, you definitely want that flat for stability once your foot comes down.
FigureSpins - are you sure we are talking about the same expert - the one I mentioned to you in the private message concerning the PSA conference?
I had a long talk with him today about this question. He says that he would never have told you that you want a separate heal rocker, or a separate tail rocker, on a figure skate. (Hockey skates have much more complicated rocker curves.) He bases the profile he creates on all MK blades a roughly 25 year old template from MK, which contains a single spin rocker up front, connected to a principle rocker throughout the rest of the blade, Likewise, he applies one of several rocker curves to other brands of skate. But in all of them, everything behind the spin rocker follows the same rocker radius.
He says that if he showed you otherwise on a blade, it was to demonstrate that something had been done wrong. In his opinion, many individual blades come from the factory shaped inaccurately. For example, some blades are shipped that have had concave rocker curves in part of the tail, to use extreme examples (he collects the most extreme cases he can find, and delights in showing them off).
He makes minor variations to this profile in spots, on one or both edges, principly up front, to make it easier to perform specific high level figure skating skills, for those skaters who require it, just as good hockey sharpeners occasionally do, for much the same reasons.
However, other experts might well shape blades differently - there are no published standards. And there are specific ways in a sharpener can accidentally add the features which you describe, especially flattening out the middle, and I (not he) believes that ordinary skating will significantly wear the blade down most in those places you use it most - i.e., in the ball and in the middle, for me.
That said, I may at some point explore placing a minor sweet spot at every point on the blade where I turn or spin. And because sharpeners had flattened my blades' tail a long time ago (probably without intent), I thought for a while it was desirable. I've stopped doing it, but others are welcome to there opinions.
ISk8NYC - I assume that your sharpener creates these features on purpose. If it is a feature you like, then it makes sense for you.
A lot of people like what our expert produces, and travel far to get to him - but other people from our area travel far to get to someone else.
I claim that when people talk about a sharpener being good or bad they mean many different things, like when they talk about . At the lowest end, they mean the bad sharpener produces accidental artifacts, and has little control over what he or she is doing. At the upper end, it is like a good or bad cook - they like or don't like what the sharpener produces. If a skater gets used to the specific features a sharpener (or boot technician) produces, and likes the results, the skater should stay with that sharpener or boot technician, and will be unhappy if they move around from professional to professional at random, picking who ever happens to be most convenient in any given week.
I have not at this time talked to the production managers or other relevant individuals at the blade companies who control the theoretical blade shapes they wish to produce. It is conceivable that our chosen expert does not have up to date or accurate information on what the individual blade companies produce. This is the best I have at this time. But I still have a lot to learn - I've never denied that.
When I use words like "I claim" or "I think", I mean that to imply it is a personal opinion, one which some others would likely to disagree. I hope that is obvious.