With the Stone Grader SP-650 you can change the grit size of the Tormek original grindstone to give a finer sharpening surface. The other side of the Stone grader is used to maintain the grindstone, bringing new abrasive grains to the surface for an effective sharpening.

The Tormek Original Grindstone is designed so that it can be treated with the Stone Grader to change its quality from fast grinding to fine sharpening. This has obvious advantages. Once you have created the desired shape on your tool, for example a chisel, you can get an even finer edge using the same grindstone and the same grinding machine with the same jig and settings. Besides being convenient not having to change equipment, you are guaranteed to get exactly the same edge angle. 

If you want to adjust the stone to a finer sharpening, press the fine side of the stone grader towards the stone surface for about 30 seconds. This will alter the function of the surface of the Tormek Original Grindstone (220 grit) making it work like a 1000 grit stone.

When you want to go back to the original 220 grit, simply press the coarse side towards the stone for a few seconds until you can notice the stone surface changing. To keep the stone fresh and efficient, use the coarse side of the stone grader when you see it is needed. Press it firmly with your hands for about 30 seconds. This process does not place excessive wear on the grindstone and can be repeated any number of times.

For changing the function of the grindstone. The fine side grades the stone for a 1000 grit finish. The coarse side of the grader reverses the stone to normal fast grinding. Activates a glazed stone.