Tormek SB-250 Blackstone Silicon Stone
With the new generation of edge tools becoming harder and containing alloys which make them tough to grind.The Tormek Blackstone silicon SB-250 is designed for hard materials and fast sharpening. It delivers fast steel removal on HSS and exotic alloys and can ‘touch up’ tungsten carbide. The key to removing material efficiently at low rpm is very sharp grains with high hardness and relatively fine grit size. The SB-250 is made in the same grit size as the original Tormek grindstone and can be graded with the stone grader for fast material removal or fine surface finish.
Tormek Blackstone Silicon has been developed for shaping and sharpening* HSS and other exotic alloyed steels. It can also touch up tungsten carbide. It does not offer faster steel removal on ordinary carbon steel than the Tormek Original Grindstone. The combination of abrasive hardness, shape and grain size is optimized to work efficiently at the Tormek system’s low RPM. Its faster material removal is an advantage especially when shaping tools with a large bevel surface, where the grinding pressure is limited, for example, planer blades and woodturning skews.
The grit size 220 is the same as the Tormek Original Grindstone and can be altered to work like a 1000 grit stone with the Stone Grader SP-650. Thanks to its sharp and relatively small grains, the Blackstone removes hard steel efficiently even at low grinding pressure. It can even touch up tungsten carbide, where the tool already has an established shape.
A distinction should be made between the shaping and sharpening of a tool. When shaping you remove steel to achieve the shape and edge angle you want. When sharpening you just touch up an existing shape to renew the sharpness.