At the 15th March 2026 meeting of RMTC, Richard Juday gave a talk on how he does sharpening. He opened with the comment that RMTC already has the largest head start of any group he might address on the topic, and thus the talk should be regarded as relating to his personal practices rather than being authoritative on sharpening in fully general application.
Sculpting has two basic forms: subtractive (e.g. chipping away at marble) and additive (e.g. blobbing on more clay). From the Web, now: There is an unlikely tale about the brilliant Renaissance artist Michelangelo. He was asked about the difficulties that he must have encountered in sculpting his masterpiece David. But he replied with an unassuming and comical description of his creative process: “It is easy. You just chip away the stone that doesn’t look like David.”
Tool sharpening is decidedly of the subtractive form — all you do is get rid of the dull parts of the blade. The woodworker assaults the surficial material occluding the underlying really sharp objective edge. (Richard wrote that, don’t blame Steve.)
Richard displayed The Complete Guide to Sharpening, a book by Leonard Lee, the founder of Lee Valley Tools. Publication date is 1995, and Leonard died in 2016, but this is the finest and most complete sharpening book in Richard’s collection. The variable structure of wood itself, illustrative electron microscope photography, and more give great insight into what you are trying to achieve.
Richard has been professionally active in optics, and he brought in some optics tech that could apply to sharpening. Optickers and woodworkers both want flat reference sources, though requiring vastly differing precisions. A woodworker is happy with a flat that is within thousandths of an inch overall, whereas the optics guys want a reference to be flat within a micron, or 0.00004 of an inch. Woodworkers will acquire a diamond flat to re-shape their stones, relying on the diamond flat makers to themselves be flat. But here you are, in your shop, with a bunch of stones, no diamond flat at hand, and you want all of your stones to be flat. Here’s how you do it. Suppose you have three stones, A, B, and C.
Grind A and B together until they are in intimate contact, knowing that the surface will be spherically curved. Next, do the same with B and C; just as with the AB contact there is still a spherical nature to the BC surface, but it is closer to flat. Now grind A and C together until they are in intimate contact, and you are closer yet. Go around again, until intimate contact is immediately achieved on each grinding. Only flat surfaces will have that character, and Bob’s your uncle.
Jigs are fine, and necessary, particularly if a set of chisels (for example) all need to be done the same, or you want to do minimal material removal from a previous sharpening, or you are just touching up the microbevel. Otherwise, with experience you will be happy with eyeballing and hand-held operation on your rough utility anywhere-in-the-shop glue-scraping chisel. Use a marker pen on the ground surface to show where you are working, since one recent shiny patch looks just like another, and you want a shiny patch that extends exactly to the cutting edge. It is useful to remember that only the 1/32 or 1/16 inch at the edge is necessarily to be polished to a mirror finish, since that’s the part actively involved in severing chips from the base wood.
Suppose you have a fine new expensive 9×12 inch granite surface plate that is truly flat from the woodworker’s perspective. And now you want to flatten the sole of a plane or a waterstone. You could, of course, abrade directly against the granite, but you will promptly cause it not to be flat anymore. Instead, wet the plate and set down a sheet of wet-or-dry silicon carbide paper (rough side up!) of the right progressively finer grit, and you will greatly extend the utility of your surface plate.
Richard talked about the 600-grit CBN (cubic boron nitride) wheel recently mounted on his Tormek-8 in comparison with the Tormek’s original aluminum oxide 200-grit wheel that is supposedly gradable to 1000.
CBN wheels are a new addition to woodworking. They act faster and run cooler than a vitrified stone, though they are probably not so absolutely immune to overheating an edge as is a water stone. In fact, though the CBN wheels can be exposed to water for cleaning, leaving them in water is damaging to them. Of common materials, CBN is the closest to diamond in hardness. Thus CBN wheels reputedly will never wear out in sharpening steel blades, lifetime warranties being evidence of that claim. The CBN wheels generally permit flattening on their sides in case the mild hollow-ground nature from a wheel is objectionable; don’t do that with vitrified wheels. As yet (a couple months) Richard is pleased with the new wheel, and he showed an example of a knife that was made really too sharp for kitchen use in a matter of three or four minutes using the CBN wheel and stropping on the paste-charged leather wheel on the other end of the Tormek’s axle.
Some chisel and plane blade jigs by Lee Valley Veritas were displayed that included indexing for repetitively positioning a chisel or plane blade against the wheel. Additionally, the jigs have the rollers on eccentric axles so that after initial grind, a blade can be ever-so-slightly raised so that after grinding, polishing can be confined to just the very edge of the cutter. The plane-blade jig’s roller is slightly convex, so that a very slight curvature is imparted on the blade. This prevents an exactly square blade from leaving dig marks at the corners, a useful feature when surfacing a large area.
A severely hollowed small dual-grit silicon carbide stone he has used for almost seven decades made its appearance. It is more a relic than a generally useful tool, but what the heck, look around at our display tables. And at the guys tending them.