Can you provide advice on how best to sharpen these delicate chisels? I know how to do so on regular chisels, but have patchy success with the tiny ones using shaped slip stones etc. Thank you.
I sharpen under a microscope. Actually I do everything under microscopes ( I use Bausch & Lomb Stereozoom Binocular Micro- scopes, models 4 or 5 only due to depth of field considerations). I bought my scopes from ebay. I mostly use 7x enlargement for sharpening. You can actually see everything you are doing at 7x. At a 1000 grit, You can get a mirror finish on a .01" chisel. You can also get eyeglass/headset type magnifiers that will do 6x to 7x or thereabouts: good enough for chisels. I have never used one but I am told they will work just fine. I do not have a source since I do not have a need. I am a firm believer in microscopes.
I have heard it said that, "if you can see it, you can probably build it". That is probably 99% true. If any questions, let me know.
Tips(I forgot): 1. use mineral oil for a lubricant. Get at Walmart pharmacy. A quart for a buck or two (probably last a century or two), 2. you can use very small flat stones (with an inch or two max dimension) to keep the cost down. You do not want or need any special curved/shaped stones, 3. buy stones from Woodcraft.com (they have lot's. 400 to 1000 grit will do - or whatever works), 4. DO NOT use any mechanical grinding wheels, they will destroy your drills in a microsecond through overheating and turning the metal blue. Once the metal turns blue, the metal turns soft as butter and is useless for anything. Throw any blue drills away, 5, not all drills are equal. Some are top-notch superb hard metal and keep a sharp edge for a long time and some are just plain soft crap. You can't tell the difference until you make it and use it. Throw the soft crap metal chisels in the trash as fast as you can. DO NOT waste any more time on them, 6. you can use these chisels for chiseling, scraping, drilling, temporary shimming, prying, etc. They are really handy, cheap, easy to come by, always available, no supplier problems, and they give a long second life to some very expensive small tools (the drills themselves-which may have had a very short first life. I have had some that lasted only one hole, but that is a tail for another day).