A lot of us have heard about level edges, but what does this really mean in regards to skating. I'm going to discuss briefly edges, how they are leveled, and the tools to measure them.
First, what are level edges? This is when both edges are level with each other and one is not higher or lower than the other. You might ask, well how do they get out of level to begin with? Well simply put, the act of skating wears the edges down. How much and where they wear depends on the skater but generally, the inside edges will wear more as every stride and push uses the inside edges. Inside at the toes will wear even more. The outside edges wear more while turning. So for example, if you turn more to your left than to your right, you left outside edge will get more use than the right so it will wear more. The direction you stop will do this as well.
While skating, not only do your edges wear unevenly but they will also dull. This is why you got to a sharpener, to make them sharp again. A normal sharpening does this. and re-levels the edges.
Is it important that edges are level? Yes. A skate blade can perform better with level edges. It will grab better and track better. However, there is a misconception that the blades have to be perfectly level to achieve this. In reality, this is far from the truth. Do you know you spend most of your time skating on un-level edges? After skating on a fresh sharpening for just 15min your edges can be measured out of level. The wear I spoke about above will throw them off. But yet, you can continue to skate fine for about 4-6 hrs of skating with no issues until of course when the edges are totally dull. A slight off level does not effect skating. It's generally known and has been tested that skaters cannot notice or is skating effected by a edge that is un-level by 3/1000" or less. While this sounds like a lot off level, it really isn't.
There are several methods to check for level edges, balancing a quarter and viewing visually is the most popular, but some will use the various magnet edge checkers that are out there on the market. Here's a couple of examples. We have 3 different models here in our store. All will come up with a different reading on the same runner. We used same runner in the two pics below and as you can see measurements are quite different.
Keep in mind these are not precise measuring instruments and are not very accurate. They have a margin of error of .001 or more. All they are is a bent piece of aluminum with a magnet attached and the base has painted viewing lines. These are quick checkers, not precision tools This is why we do not rely of these to measure edges and never use these to align our machines. These checkers are not accurate enough for that. As you can see in the first pic above, it's reading about 3/4 of a 1000 of an inch off. Some sharpeners will use these to set up their machine, but what they are doing is adjusting their sharpener to the gauge's margin of error, not to actual level. So the machine is set up off level.
We do not use crude magnet checkers to set up our machines or to check your edges. We use a precise sight checker along with feeler gauges. With feeler gauges we can measure to be within .0005" (one half of 1/1000". But being off a little is OK though, ice skates do not require perfection. Tools to measure less than this can cost thousands but aren't really needed for sharpening skates. Skaters will not notice any problem or deficiency while skating even if the edges are off by up to .003 (3 thousands). As discussed above, most of your skating will be on un-level edges and you don't even know it. Well you do now.
Another reason the magnet checkers are inaccurate is that the accuracy starts deteriorating from the first time they are used. As you can see in the two pics below, a skate blade's sharp edges put scrapes/gouges in the level part of the checker. A small scrape or indent in the soft aluminum can throw of the readings quite a bit more.
We use a couple of cool tools to set up our machines. For FBV machines, where the distance between the flat spot and tip of edge can be as small as 1/2 of 1/1000", we make a rubber cast of a sharpened blade, then view it thru a microscope to measure the edges and adjust machine alignment as necessary. In the pic below, you can see the V on one edge and not on the other. Accordingly, the skate holder would need adjusting to center it.
Our sight checker is a wonderful tool. As you can see in this pic below of a hollow being tested, both edges are touching the tool. This blade's edges are level. If one edge is high or low, you could see a gap and light between the checker and the edge. In addition to checking if a sharpening is level we also use this checker to verify alignment of our machines.
Lastly we use various feeler gauges to test how much a blade is out of level. We can check accuracy down to low as as .0005, the size of our smallest gauge. .0005 is the smallest feeler gauge available. Our .0005 gauge is so thin, holding it is like holding a piece of saran wrap, that's how thin it is. In the pic below, the .0005 gauge will not fit in between the edge and the checker, meaning edges are level to less than .0005". Can't get much more accurate than this.
In conclusion, we discussed what level edges are, what you need for skating, what measuring margin of errors are, quick measuring tools, setting up sharpening machines, and then the tools we use to make sure edges come out level after after a sharpening. If you have any questions, feel free to send me an email.