update - diamonds and lapping plates
Tim of San Leandro
>Here's a bit more I've found out for my situation.
I use diamond compound in oil (Crystalite is the manufacturer) and steel lapping plates. Plates are cold rolled 1018 carbon steel, lapped *flat* against a granite reference plate using abrasive papers. I use mineral spirits as a *lubricant* or whatever it is to remove swarf and such. I'm going to try some others, as I *think* the MS is a bit oilly for the finer grits. I'm going to try isopropyl alcohol (rubbing alcohol/disinfectant is 70% isopropyl alcohol/30% water).
325 mesh - as per Bill's findings, it doesn't embed well into the steel and kinda rolls around a lot. when first applied, it cuts like crazy though.....800 mesh (30 micron?)embeds well into the steel and cuts quickly - not quickly enough that you'd take a squared blank of hardened tool steel and grind a bevel on it, but much faster, IMO than the pink 220 grit waterstone I had before.
8000 mesh (8 thousand MESH, not grit) diamonds - quickly remove the 800 (8 hundred) mesh scratches and produce a scratchy mirror surface.
50,000 mesh diamonds - scratch free (ummmmmm.... if you can manage to keep the plate uncontaminated :sob: :cry:) mirror polish. I'm wondering if these embed into the plate or not...I seem to have to recharge the plate more with this grit than the 800 or 8000 mesh plates. It may be the oilly MS issue...
That's all I need.
some notes:
make a box/case for the plates and keep them covered when not it use.....I'm thinking I may be getting dust contamination on the 50,000 mesh plate. Buy paper towels at Costco/Sam's/Your Preffered warehouse store. I sharpen free-hand, no jigs or such. I know I saw one jig where the jig rides on a different surface than the waterstone (lapping plate here), but that's about the only type of jig I'd try. Or you might visit Brent Beach's site and copy the jig he makes/uses. When I say I sharpen free-hand, I use "sharpen" quite loosely due to my lack of technique....I think *grinding* free hand might be a bit more accurate : ).
No, I don't clean the plates at all or try to wash away the swarf. I squirt some MS on at the beginning because it does dry up and then squirt more on as needed if I'm sharpening a few different tools.
For the 800 mesh diamonds....don't add too much diamond after initial charging...too much and the diamonds roll around and abrade the lapping plate.
The plates are 3/16 thick and 8x3...the typical size of a large waterstone. It works well for me, but if I order up more plates, I'll likely go more in the Shapton Hippo stone range...10-12 inches long by 4-6 inches wide.
Tim