The Atoma Diamond Sharpening Plate #600 sits at a grit most woodworkers underestimate - and that's precisely what makes it worth understanding.
An edge is only as good as the two surfaces that create it, and the weaker one always wins. On small surfaces like secondary bevels you can jump straight from 400 to 1200, but on the larger flat side of a plane iron or chisel, that gap is too great and the results will show it.
At 29 microns, the #600 isn't dramatically finer on paper than the 40 microns of a 400 grit plate - but the difference in the surface produced is significant. In practice it does around 80% of the refining work you'd otherwise ask of the 1200, for a fraction of the effort:
- Both plates last considerably longer as a result
- Flattening chisels and plane irons becomes more controlled and efficient
- Your sharpening progression through the grits is smoother and more predictable
A logical addition to any serious sharpening system - and one that repays the investment many times over.
The critical quality indicator to look for in a diamond sharpening stone is monocrystalline diamonds (each piece of grit is a single solid diamond) they are more expensive to produce but much more durable than polycrystalline diamonds.
The Atoma diamond sharpening plates we have inspected have all been remarkably flat.
Plate size: 210mm x 75mm (8¼" x 2⅞")
Do:
Use plenty of fluid and light pressure.
Fading the pressure out gradually as you finish will leave a finer scratch pattern and reduce the amount of strokes you need to take on the next plate.
Use light pressure, the diamonds are cutting tools and if you let them do their job they will serve you well for many years.
Expect all diamond surfaces to have a vicious bite initially and then gradually bed in over the first few uses, this is completely normal. As long as you keep them clean and cool and avoid using too much pressure they will cut like the wind for years.
Use liberal quantities of some kind of fluid on them, water with a few drops of dish soap, window cleaner, water treated with HoneRite Gold all work well.
Light contamination can be cleaned from the surface with an ordinary pencil rubber (eraser), if they get really grubby, moistening the surface with a bit of white spirit will help to lift the crud.
Don't:
Avoid using them with soft metals like brass, wrought iron or aluminium as these will gum up the surface and are impossible to remove.
Avoid using them for the bevels of laminated blades as the backing material is often soft and will gum up the surface.
Avoid using too much pressure, especially on the edges, the diamonds themselves are virtually indestructible, the electroplating that holds them to the surface will last much longer if you don't lean on it and scrub.
Avoid using oily lubricants on them, the greasy residues attract dust which will gum up the surface.