I hope you don't mind if I add something to a thread that was started four years ago. I just joined this forum and the first thing I read was this very informative discussion on microbevels. Unless I overlooked something, there appears to be no mention of using a sharpening steel to create a microbevel. Long ago I read an article by John Juranitch from Ely, Minnesota, in which he writes a few things about microbevels. I tried them, was only mildly impressed and went back to the roughly 17-degrees-per-side free-hand method I had been using forever. Then, at a flea market, I picked up an old flat sharpening steel, basically a steel with a much flatter form and with well-worn and unaggressive grooves. The "blade" on mine is 22cm long, between 3cm and 4cm wide and about a half a cm at its thickest point.
One day something moved me to increase the angle while steeling one of my kitchen knives, and afterwards I discovered that this action had actually created a microbevel, easily seen under a 10-power magnifying glass. To my amazement I discovered that the microbevel did not appear to decrease the sharpness of my knife at all, it actually felt sharper, possibly a result of the altered edge geometry, and it continued to easily slice through everything my kitchen has to offer.
Ever since then I have been sharpening my knives as I always have, something like 17° a side, working my way through several stones down to very fine, then finishing with leather. But after using a knife in the kitchen for a while, I now run it over the surface of this flat sharpening steel, while increasing the angle considerably. Without measuring, I'd guess that I steel it at around 25° per side, certainly more than 20° and quite a bit more than the 17° I use with my sharpening stones. After all these years I now have something of a calibrated feeling in my wrist to differentiate between the two angles. The results are threefold: A highly polished microbevel can be detected under good lighting, the sharpness remains impressive, and I now haul out my sharpening stones much less often than I used to.
Your classic form of sharpening steel can also be used, but the smaller the radius, the higher the pressure that is transferred onto the edge, so it would be wise to experiment prudently. There are also old steels to be found which, if sawed though the middle at 90° and viewed from its end, have a cross-section that resembles a square. Rather than being a round rod, the sharpening steel consists of four narrow (1cm) sides with four corners, like a long square bolt. They're great for steeling all kinds of things, and due to the flatness of the four sides the pressure applied to the edge is minimal.
I admit that this "new" method has a drawback. Ever since I was a child, I have been collecting sharpening stones from around the world, and I have always loved sharpening knives, do it for all my neighbors and friends just for fun. Now, all of my nearly 200 different stones are used only about a third as often as once was the case. I may start collecting sharpening steels.
Sam