Rob Cosman's Diamond Stone 300/1000 Grit
I recommend and use this 300 / 1000 grit double-sided diamond stone as an essential part of my tool sharpening method. These diamond stones are custom made for us and I think they are the best on the market today.
Precision made double-sided diamond stone 3" wide x 8" long.
Ideal for flattening chisel backs and sharpening plane blades and chisels.
The metal plate is precision milled flat to within +/- 0.0005 of an inch in length and width. After electroplating the surface is flat to within +/- 0.002 of an inch in length and width.
Fine 1000 grit (5 micron) on one side and coarse 300 grit (50 micron) on the other.
Clearance channels on the coarse side produces a faster, cleaner cut.
Use the coarse side for flattening your water / ceramic sharpening stones and on your chisel and planes when you need some aggressive cutting action.
Use the fine side for sharpening your secondary bevel on plane blades and chisels and other edge tools.
Comes complete with a non-slip mat.
This 8 inch x 3 inch precision milled, flat piece of metal (+/- 0.0005 inch of flatness), is impregnated with Monocrystalline industrial diamonds, but what makes these stones different from the competition is how they are affixed to the stone. The typical diamond stone has diamond chips adhered to a thin metal plate. The monocrystalline diamonds are attached to our stones with the following process:
The flat metal plate is placed in a tank of nickel which is heated to a certain temperature. Then an electrical current is added which electroplates the nickel onto the surface of the metal plate. The nickel solution includes the diamond particles. The nickel is grown around the diamond particles so that they are buried 2/3rds deep leaving 1/3rd exposed (the designed abrasive cut). Similar to the appearance of an iceberg.
The 300 grit side of the diamond stone requires a one time break-in procedure. There is an excess layer of diamonds which needs to be removed before the surface is at its optimum. Break-in the stone by rubbing a piece of steel (a screw driver shaft, plane blade, etc.) over the entire surface of the 300 grit side for 1 minute. Rinse and wipe off the diamond stone; it is now ready to use. Failure to break-in the 300-grit side can lead to cross-contamination of water stones.