These cheap modern microscopes are just awesome for a sharpening!
Great theme, I like. I will share my little experience. These are my EDC knives, Buck 501 always with me (he is the main), and 1-2 of the rest periodically with him. At home I have a two-layer stone for sharpening Craftsman, it looks a lot like 2 ply Norton Crystalon. Here, these stones are also pre-impregnated with something oily. For final sharpening, if necessary, there is a piece of washita and a piece of black arkansas. The best lubricant I have found, oddly enough, is Dove soap, which has a cream additive. Forms a good suspension and after it the stones are clean, that is, metal particles do not clog the surface.
I carry these 3 stones with me, they are small, but they are enough to restore sharpness if necessary. In my opinion, hiking with a knife without a sharpening stone is like carrying a flashlight without taking spare batteries or a gun without additional cartridges. A knife will be useless if it cannot be sharpened. I used to wear only 1 fine india stone, but then I realized that it does not remove metal quickly enough, then I added a medium diamond stone and then a coarse diamond stone.
The most difficult thing in sharpening, in my opinion these are 2 things. 1 - remove burr, unfortunately this is not so easy, sometimes you seem to sharpen the knife very sharply, but you make a couple of cuts and it is dull again, sometimes it is bad hardening of steel, but more often it is due to a burr that creates the appearance of sharpness, but falls off / wraps at the first load. Each copy has its own approach, I had several 103, a 2 of old ones from 440C (pre 67) and 425M (1989 stamp), and a couple of fresh. On the old ones, the burr was almost not formed, it was very small after a fine carborundum and left completely on washita / arkansas. On newer ones, the burr is more persistent and I have to do all sorts of strange things to remove it. On 501 S30V, burrs are almost not formed, they are very small, but very durable. And from here came the second thing - you need to know when to stop))) I can spend hours trying to get rid of burrs and sharpen so that the knife can easily cut through hair, it looks like OCD. And in reality it is not necessary, many knives in real work will dull equally quickly, it does not matter if they are finished at 400 grit fine india or higher 4000 grit arkansas or water stone, so I end my 103's with fine carborundum (~320 grit). But this applies to hunting and EDC knives, which deal with dirty animal skins (sand / clay) and various construction / packaging materials, which are also often contaminated with abrasive particles. For tools working with wood and clean materials (cutting leather for example) - chisels, cutters, scandinavian and leather knives, planers, etc. it makes sense to use finishing stones with a very high grit, but this is already a topic for another section on sharpening.