I've gotten handy dandy at sharpening over the last few years and here are some of my thoughts on the subject: Hope they help some find a better/faster way to sharpness.
There is only one sharp. Fully sharp. Anything else is not sharp and may be due a resharpening-depending on the application. I do gag a bit every time I hear "razor sharp!" because I kinda know what that is (shaved with striaghts now for at least five years-never with any one else's edge, or a new razor. Cutting hair is not the same as shaving a face
comfortably, that's all I'm sayin'.
The purpose of the edge/tool should be the biggest influence on the angle and shape of the bevel. Example-Axes use a much wider angle than shaving razors. But the ultimate sharpness of either is obtained the same way. Make the bevels meet
* and then polish them up to the needs of the application. I've not studied the numbers lately, just isn't necessary.
*There's only one bevel on a chisel/plane iron, etc. Razors are a bit easy, in that the "bevel gauge" is built right in. Chisels and hatchets and knives I sharpen by eye and feel. Took a while to get to this point. I've used lots and lots of gizmos. Now I use diamond plates mostly, coarse and fine by DMT.
If the grind it right (relief/hollow), the primary bevel will appear even and of equal widths on each side on a double-bevel item.
Then feed the edge into your stone starting below the proper angle (or bevel as is on it), raising the back edge slowly until you feel the edge start biting into the stone. Back off that angle, and use several strokes, just under it (lowering the back end minutely), then finish with some good strokes into the "bite". Develop an even burr, then do the other side.
If you never get a burr, you're not getting fully sharp. The unsupported steel must curl over the offside, once there is nothing there to support it. THIS is how you can be sure (blindfolded) that you've gotten the edges to meet. Blades sharpened (and even polished to high mirror luster--don't ask!) can "feel sharp" without ever getting _quite_ to the burr stage, BUT They aren't properly sharp.
Also the method described yields a very slightly convex bevel, which supports the cutting edge nicely-BUT most importantly the shape of the bevel is maintained. I don't measure anything like that anymore. I now do it all by feel and sight and performance.
Paul Sellers teaches this in sharpening plane irons, chisels, knives. He uses a three-stone (diamond plates) setup, but I've only the two right now. I have a dozen other stones for fine work-but really only use them on shaving razors. A fine DMT will get me all the keen edge I need for knives and similar. I'll knock off the burr with a ceramic stick if one is handy, with very careful and light strokes otherwise.
Pushing into the stone is a bit tricky with waterstones and sandpaper, but can be managed once you get it. Diamond plates are fantastic. You can get the same bevels pulling your blade, but the burr will be different and I've not done it that way much. Wet/dry sanding paper over a flat surface like glass or tile or trued steel works for lots of things and everybody has some handy. I generally use a file instead of paper, then to stones. Waterstones are generally reserved for my Japanese cutlery and razors, but many use them for chisels and such. I'll use high-grit paper or "barber stones" to touch-up and edge at the bench sometimes.
But fine work can be done with a file. The last time I sharpened another fellow's machete (new guy, surveyor that I was training), that fellow wound up getting three or four stitches later in the day. He dropped it (and started to catch it). Bloody mess.
Paul Sellers probably does a better job of teaching it than I do. Also GSSixgun is one of my razor gurus. Razors are somewhat different, but you just have to remember that finer angles and finer grits means smaller burrs, but you still have to have a good bevel and get to the point of burring. There is no sharp otherwise. Sharpening razors is where I finally put it all together. Paul Sellers came along later (to me) and does as I do. He has videos, I don't.
I can sharpen a sawchain in my sleep too...but that's more about cleaning up the edge and getting the proper angles without so much reliance on burrs. But then I cut seasoned Osage with aplomb.
