Refer to this thread https://skatingforums.com/index.php?topic=8701.0 , Reply #12 and #13.
So, unless you polish the inside (hollow) surface as well, I don't think you gain much advantage (if at all) in using an ultrafine 5000 grit (vs a 320 grit or at most a 600 grit) whetstone to polish the outside surface only [as discussed in a previous post, PBHE (http://precisionblade.com/index.php/product-catalogue/) supplies a manual unit for polishing the hollow; and I've seen listings for polishing wheels for commercial powered sharpeners, though I've never come across a tech who uses one].
Great discussion thread! These are my thoughts based on my experience with the Incredible Edger machine that I have used since 2006. I’ve been fortunate to be able to experiment on my own blades to test different ideas. I am mostly an ice dancer but do some spins and single jumps plus moves in the field.
CHROME RELIEF BAND SMOOTHING
I have experimented with polishing the chrome relief band on skates because years ago I noticed that when I had to clean rust off the chrome relief band, the band became smoother. As Kaitsu says, both sides of the knife will affect the feel of the final product. I tried it on my own blades at the time and I could feel the difference in the smoothness of the glide. I then tried it on some of the skates belonging to other adult skaters and coaches and all of them said “I don’t know what you did different this time, but they feel so smooth”.
Since then, I’ve added that step for new blades that have a rough chrome relief band, and it has also reduced the amount of rust I need to deal with. The smoother band traps less water and is easier to wipe dry, so in the end I think I do less work by smoothing the ground chrome relief at the beginning of blade life. I check the smoothness of the chrome relief when I am given skates to sharpen, and usually will end up smoothing it again about once a heat to reduce nicks and surface damage.
The procedure is: I lay the blade on its side on my workbench on top of a smooth sheet of plastic and smooth it with a flat gummi stone, lubricated with Tri-flow or WD-40, laid flat on the chrome relief band, and spend a minute or so on each side. This is not an attempt to create perfection, particularly because I have not yet created a tool or holder that makes the process perfectly precise. However, it is a big improvement over what the blade manufacturers are providing.
Most skaters want to get every advantage that their equipment can bring them. There is no advantage in leaving the chrome relief band rough, so as long as you have enough attention to detail to be able to smooth it while holding your stone flat to the side. Marc—it sounds like you probably already have enough experience sharpening garden tools to be able to try this. The small piece of stone in Kaitsu’s photo is a good choice, as well as the Swix gummi stone that I borrowed from my ski tuning kit.
I now skate on stainless blades with no chrome relief. The sides of the blade are flat and parallel and the steel is highly polished. With level edges after every sharpening, I am consistently skating on blades with the same edge angle and with smooth sides and a pretty smooth hollow. I think it really helps to have the edge angle consistent within a small range (it will change slightly as the blades wear down from newly sharpened to their duller conformation).
HAND-POLISHING THE HOLLOW
I have also experimented with hand-polishing tools for smoothing the hollow. A tech who used to sharpen a lot of school figure (“patch”) blades showed me how to use a small chunk of wooden dowel wrapped in garnet paper to smooth the hollow after machine grinding. The adult skaters and coaches gave me very positive feedback on adding this step. Eventually, I found the PBHE website and I ordered the tools that they make for hand polishing (a cylinder wrapped in 15-micron grit sandpaper that is exactly the size of the hollow). Unfortunately, I found the holder for the cylinders to be very frustrating to use. The brass adjustment screws scratch the sides of the blade and are finicky to get centered on the blade. The holder gets very sloppy on parabolic or tapered blades. Since I had years of experience hand-guiding the dowel through the hollow, I switched to hand-guiding the cylinders and don’t use the holder at all. This produced a better finish than the dowel and garnet paper. The blade must be clamped securely with the hollow facing up to do this, because you need to both see and feel the travel of the dowel or cylinder. I also very strongly recommend cut-proof gloves because I sliced my thumb open (requiring 3 stitches) when my hand slipped. The disadvantage of this method is that if your hand slips and you run the cylinder up over the edge, you dull one single section so you have to regrind with the machine and start over with the hand polishing. Not the ideal system, but I did this for about a year and a half while slowly troubleshooting through my machine to reduce the chatter it was producing. It allowed me to provide a better finish than my machine could produce at the time. (I have now realized that the spindle bearings were aging and that was the biggest source of vibration.)
After tearing the machine apart and rebuilding it multiple times to reduce vibration, plus replacing parts, switching to Blademaster ruby wheels and learning how to balance them (thank you, Kaitsu!), I now get a considerably improved finish with only a tiny bit of micro-chatter. I’ve compared it at 15x magnification and it is clearly smoother than what I was achieving previously with the hand tools. After skating on it, I can tell it is smoother. It feels superb right away. Previously, it would take about 3 hours of skating on freshly sharpened blades before my school figures felt smooth and normal—there was always some increased drag on the freshly sharpened blades. Now they feel smooth from the first moment on the ice. I think I could improve it further with the hand tools, but it may be to the point where the difference would be undetectable.
I had previously been convinced that the hand tool was a critical final step in the process, but now I can see it is just one of the ways to improve the machine finish, and may not be necessary. Also, you will need cylinders to match every ROH, which gets expensive. Eventually, I want to develop a better holder for the cylinders to see if I can get a more perfect finish, but that’s on my list for future projects.
Marc—before you invest in the hand honing tools, I recommend seeing what kind of finish your new machine produces.
DE-BURRING AGTER GRINDING
In all cases, I deburr the edges after I finish grinding. I can see and feel the difference in smoothness and also feel the difference on the ice. Edges that are not deburred are very grabby and tend to make skaters hate having their blades sharpened. I use a ceramic stone for this, a 5mm-ish cylinder that I was given for this purpose by the tech who showed me the dowel-and-garnet-paper technique.
LINING UP THE WHEEL WIH THE BLADE
I follow the same procedure as Kaitsu. I was trained to grind a tiny spot to determine alignment, but once I was working on my own I became concerned about creating inconsistencies along the blade. Turning the wheel by hand scrapes the marker lines without removing extra metal. I have tried to check lineup by viewing the blade and wheel from the side, but unfortunately it only gives you a rough idea of lineup. Once you have successfully sharpened one blade in a pair, you will probably find that the second blade is lined up close to that same position, but never assume that a blade is the same as it’s partner. I measure every blade at at least 3 locations (front, first stanchion, second stanchion) with a precision square many times through the process. I’ve heard a lot of people say the “eyeball it” and that they “have a pretty good eye”. It’s really difficult to see tiny differences in edges as close together as on a skate blade, so using a tool is the sensible approach. Using the square is reliable and sure. A good precision square is a really important investment.
YAY FOR THE FORUM
It’s frustrating when no one else around you has any interest or experience with sharpening. It took me years to find this forum and to have the opportunity to discuss sharpening details with other techs and it has been extremely valuable to connect with this group. I have to add that it is a tremendous relief to find that there are others out there that are having the same questions and figuring out answers. Since I know I have a tendency to overthink things (probably a pre-requisite for being an engineer), it’s wonderful to discover that I’m not alone. For those of us who don’t want to be “plug-and-play” techs, this is a great place to share. I’m actually kind of envious of people like Marc who can get started while having access to people with expertise. So much less agonizing over the startup process! Have fun with it and ask all the questions… you will be glad you did.