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Author Topic: People who should buy basic measuring tools for their blades.  (Read 501 times)

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Offline Query

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People who should buy basic measuring tools for their blades.
« on: February 18, 2022, 02:42:39 PM »
In another thread I suggested that skaters, even those who don't sharpen their own skates, should buy basic inexpensive tools that help them to see if their skate tech is done a good job, and to look for signs of excessive wear that indicate blades might best be replaced, and that they should learn to feel the edges of their blades to look for sharpness. (They should also learn to feel the edges to look for proper edge alignnent.)

Thinking about it a little more, I'll add a few more ideas.

Obviously, conscientious skate techs should buy such tools too -as well as some of the more expensive ones.

Some skaters are two young, too unsophisticated, or are otherwise incapable of taking even the basic technical measurements needed to do this. Their parents, or the equivalent guardians who take the kids to the ice or otherwise manage their skating time, should get such tools.

Precisely because there is more than one possible cause of certain skating problems, it also makes sense for coaches to buy such tools too, even if they don't sharpen their students' blades. In addition, a coach is a somewhat authoritative figure who can hopefully provide feedback to a skate tech to improve their skills.

I know educating the skate tech is a lot to put on the coach, because they have a lot of other things to learn and deal with. But I think a really good coach would do exactly that, if they couldn't find a skate tech who already knew how to handle figure skating blades well, and chose to do so.

For the coach to succeed, several things have to be true: The coach has to know what to look for - AFAICT, a lot of them do. The skate tech needs to want to improve their skills. They have to be able to improve their skills. The pro shop manager has to allow the skate tech to interact with customers, including the coach. If the skate tech is not the pro shop manager of the pro shop, the manager has to allow them sufficient time to do a reasonably good job.

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I won't repeat my list of suggested basic tools for ordinary skaters to buy from that thread .

There is a tool I didn't mention, a good condition micrometer, or an equivalent calipers, to determine how much metal the skate tech is removing (at a number of points along the blade) with each sharpening. But in fact, that is one of the most important measurements, because that amount of metal removed is essentially inverse to the potential lifetime of the blade. It also lets you test whether approximately the same amount of metal is being removed from different parts of the blade. It is also more difficult to use than the others, and despite the cost, I personally think it worth it, though some might disagree.

I hesitated to mention the micrometer because of the cost.

For the most part, I guess you have to mail order it, for several hundred dollars, if you want to be able to consistently measure changes at carefully marked points of on the order of a few microns (about 0.0001 inch) at most. (There are callipers that can do that too, but the ones capable of that seem to be even more expensive, unless I looked in the wrong  places.) In addition, while the less expensive tools might perhaps find other uses in the home (though it is clear that everone will find other uses for a radius tool), the micrometer probably won't. It is a delicate tool that needs to be taken good care of, without placing much force on it, and isn't all that useful for the ordinary measurements that you might need for basic home repair.

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Incidentally, though this may seem a bit off my own topic, I found my first micrometer, used, online, but it had about 0.0003 or 0.0004 inch inconsistency, despite my best efforts, and the seller's claim it was in excellent condition. It did not have a ratcheting knob to help create consistent contact pressure. I'm not sure if that is the problem, but maybe it is a factor. Or maybe I didn't figure out how to use it right.

I've had several more or less high precision cailpers that I bought new, with at least that high an inconsistency, from sellers with good buyer feedback, though none have 0.0001 inch (or equivalent metric) precision.

So, as I more briefly mentioned in another thread,  I found my most recent micrometer in another way, which is probably crazy, and also wasted a lot of time. Perhaps it would have made more sense to buy the several hundred dollar tool from a reputable source, but I simply don't have enough experience to know. Maybe 0.0001 inch consistency, which I wanted, is too much to ask, at least after a bit of use, at reasonable cost - though Kaitsu recently linked to a video from this forum of him using a Russian micrometer that seemed to be consistent to fairly close to 1 micron, with interpolation - a little better.

I looked in hardware stores, including stores that sell professional grade constrution tools like Home Depot, etc. None of their micrometers or calipers even had the precision to do this type of thing. They generally read to 0.001 inch or 0.0005 inch precision. There is a several dollar sliding plastic one with a vernier scale ones (a nuisance to read, and you have to learn how) to only 1/256th inch readable precision and accuracy at best. (I would have liked a sliding one, because they probably won't damage the edge. Oh well.) My personal experience with such tools is they often aren't consistent even to their advertised precision and accuracy level. (I think they don't need to be for ordinary construction work.)

I tried to find a local store, near DC and in upstate NY, that specialized in the needs of precision metal shops. For some reason, though a couple stores claimed to, I couldn't find one that actually had the high precision and accuracy tools. Perhaps I looked in the wrong places...

I finally walked into a large Harbor Freight store, where the managers didn't choose to stop me from testing all the micrometers (about 10 or 12 of them), and most all of the calipers with the required nominal precision they had in the store. To put it gently, Harbor Freight does not specialize in high end technical measurement tools, so it was probable none of the tools they had would be good enough. I found one that was. All the others had one or another form of defect or inconsistency that would have meant they couldn't do the job. It was about $40. I definitely can't guarantee that you would find one of adequate quality and consistency if you did the same thing. The others in the store of the same brand and model, [pssob;u this one, or one similar, did not even come close to the same standards. That this one did was probably a fluke.

I looked for the ability to read from 0 to 1 inch (and/or the metric equivalent) to .0001 inch precision. I wanted them to turn smoothly, with uniform pressure, throughout their range - though as with most new tools, I had to move them throughout the range a few times to even out the pressure. (You sometimes even need to lubricate mechaical tools with a light oil to do that sort of thing. But don't lubricate digital tools - maybe some of them measure resistance or capacitance along the primary scale, which could be messed up by a lubricant.) I wanted the jaws to align uniformly square (i.e., for the jaws to close completely, at all points, with minimum pressure), and with no significant play. I didn't need absolute accuracy, only relative accuracy, so for the mechanical tools, I didn't care if they read zero when the jaws were closed. For the mechanical tools, I wanted them to return to the same reading within 0.0001 inches, if I started with the jaws closed, moved them to the other end of their range, and closed them again. I repeated that test a few times. For the digital tools, I zeroed them at the closed jaw position, and did the same tests. Some of the tools included calibration objects of a fixed length, which I used to test all the tools - I didn't care if the micrometer read that length accurately, but I wanted it to read it consistently. I wanted the read-off values to advance uniformly and in the same direction as I turned it a given amount, throughout the range. (Some cheap vernier scale tools do not - the markings have been molded in such a non-uniform way that they read go backwards as you advance through aligning the vernier scale. I wasn't sure I could obtain consistent readings if I didn't get exactly the same pressure, so I wanted one with a ratcheting knob, that worked well and with consistent pressure when I turned it , though I didn't actually require that. I wanted the resultant change of reading from inserting two sheets of paper to be double that (within .0001 inches) of one sheet.

I'm sure an engineer or technician would have thought of other tests, but that is what I could think of.

I personally prefer mechanical measuring tools, especially the ones with analog dials, because I find them easier to read and to trust (I've sometimes made mistakes when reading vernier tools, especially if I try to interpolate between the vernier markings). Also, I don't use them often enough to justify buying a lot of new batteries for it.   But the only one I found  there that seemed to work consistently enough for my purposes was a digital electronic device. Plus, if anything goes wrong with it, the instructions say it is not repairable or adjustable, whereas some of more expensive models say they are, for a price, if you send them back to the manufacturer. But it was all I could find there that I was happy with. After all that work, I simply chose to buy it, and hope it continues to work well and consistently, and that I didn't miss anything important. I shall see. :)