Flatten Coarse Grit Water Stones
You're particular about the grits of the water stones that you use for specific sharpening operations, so why would you be any less particular about the lapping plate that you use to flatten those stones? The Nano-Hone NL-4 Lapping Plate is 240mm (9-7/16") Long x 60mm (2-3/8") wide, and it is designed to flatten water stones from 120 grit to 2000 grit. That's abrasive particle size of 110μm to 10μm if you prefer microns.
Diamond Abrasive with a Difference
The NL-4 uses diamond abrasives like some other flattening plates, but with a difference. The diamonds are coated onto raised structures arranged in a specific pattern. The particular pattern used on the NL-4 has long, straight edges, and that's what makes it particularly suited to use with coarse and medium grit stones.
The primary cutting action occurs on the edges of the raised, diamond-coated structures. The arrow-rake pattern of the raised structures cuts across a stone's full surface, removing larger amounts of material efficiently.
Q. If the NL-4 is for coarse water stones, what should be used for fine ones?
A. Nano-Hone makes a companion stone to the NL-4. The NL-5 Lapping Plate for Fine Stones is the perfect plate for stones of 1000 grit or higher.
Q. Can the Nano-Hone Flattening Plates be used with any brand water stone?
A. Yes. They will work with any brand of water stone. Of course they work very well with the Nano-Hone Water Stones.