The SP-650 Stone Grader allows you to adjust the sharpening characteristics of your Original Grindstone or Blackstone Silicon. These grindstones have adjustable sharpening characteristics equivalent to between 220 and 1000 grit. The fine side of the stone grader provides finer sharpening characteristics, while the coarse side is used to maintain the grindstone and reactivate the grit for more effective and coarser sharpening.

Why SP-650 Stone Grader?

• Adjust the grit of your grindstone to an equivalent of between 220 and 1000 grit.
• Works with your original grindstone as well as the SB-250 Blackstone Silicon.
• The fine side can be used to clean your Japanese Waterstone.
• Easy to use, just press against the grindstone.
• Works with the Tormek T-8, Tormek T-4 and older models.

Fine sharpening or high material removal

The SP-650 Stone Grader allows you to adjust the characteristics of the grindstone so that they're equivalent to between 220 and 1000 grit. If you want to adjust the stone for finer sharpening, press the fine side of the SP-650 Stone Grader against the surface of the grindstone with the machine running. This will change the surface of the grindstone to give finer sharpening.

When you want to restore the grindstone to give more effective material removal and coarser sharpening, press the coarse side of the stone grader against the grindstone with the machine running for a few seconds until you see or feel the surface of the grindstone change. You can also hear the sound change as your grading takes effect.

Grindstones with adjustable grit

Tormek's SG-250 Original Grindstone, SG-200 Original Grindstone and SB-250 Blackstone Silicon are designed so that their characteristics can be adjusted from coarse to fine sharpening using the SP-650 Stone Grader.

This has a major advantage in that you can remove a lot of steel more quickly with a coarse grindstone, while also being able to do the final sharpening with the same grindstone. Besides the convenience of not having to swap equipment, you're also guaranteed the same sharpening angle because no other adjustments are made, except the grit.

SP-650 Stone Grader for maintenance

Use the coarse side of the stone grader as needed to keep your original grindstone or SB-250 Blackstone Silicon clean and effective. Press it firmly against the stone with your hands for about 30 seconds. This process creates no unnecessary wear on the stone and can be repeated an unlimited number of times.

You can also clean your SJ-250 Japanese Waterstone or SJ-200 Japanese Waterstone in the same way, but with the fine side of the SP-650 Stone Grader. Never use the coarse side of the stone grader on your Japanese Waterstone as this may damage the grindstone.