Sharpening Handbook

Tormek Grinding Wheels

Grinding Wheel	Tormek Part Num	Grit^①	Grain Size (µm)	Material	Knoop Hardness	Comments
Original Grindstone^②	SG-250 SG-200	220 to 1,000	64 to 18	Aluminum Oxide (Al₂O₃)	2,200	Grit is regraded using the Tormek SP-650 Stone Grader.
Blackstone Silicon	SB-250	220 to 1,000^④	64 to 18	Silicon Carbide	2,700	Targeted for use on high speed steel (HSS) and other high alloy steels. Can be used for ceramic blades, but is not recommended for those. Grit is regraded using the Tormek SP-650 Stone Grader. Not available in a 200mm size.
Japanese Waterstone	SJ-250 SJ-200	4,000	3	Aluminum Oxide (Al₂O₃)	2,200	Excellent for adding Micro Bevels.

Diamond Wheel Coarse^③	DC-250 DC-200	360	50	Diamond on steel	8,800
Diamond Wheel Fine^③	DF-250 DF-200	600	30	Diamond on steel	8,800
Diamond Wheel Extra Fine^③	DE-250 DE-200	1,200	10	Diamond on steel	8,800

Leather Honing Wheel	LA-145 LA-220 LA-100 LA-120 LA-121	n/a	n/a	Leather with adhered honing compound	n/a	Honing compound used with the leather wheel(s) provides the grit needed for honing the edge. Various compounds provide different grits. LA-100, LA-120, & LA-121 are profiled wheels used for honing curved tools (e.g., gouges).
Honing Compound	PA-70	8,000	3	Leather with adhered honing compound	n/a
Composite Honing Wheel	DCW-220	2,000	12	Composite with embedded honing compound	n/a

Notes & Comments

Grit comparisons are not perfect. For example, the SB and SG stone grits are measured using the FEPA (Federation of the European Producers of Abrasives) standard, whilst the Japanese stone grit is using the JIS (Japanese Industrial Standards) standard.
For more information about grits, see the Grit Fundamentals webpage.
The grit size on the SG grindstone is not changed per se, but it effectively is. This is accomplished using the Tormek SP-650 Stone Grader, and is described by Wolfgang in the Tormek Sharpening Class Part 26 (link below).
Diamond wheels are recommended for ceramic blades.
There are some who have stated that regrading the SB-250 is not possible using the SP-650. They use a diamond plate instead.

Tormek Live Sharpening Class, Part 26 - Grinding Wheel Comparison (YouTube video). Wolfgang and Sèbastian from Tormek talk you through the differences in grinding results produced by Tormek’s various grinding wheels. They also address some frequently asked questions:
- How much of a difference is there between our diamond wheels?
- Why does Tormek use diamond vs. CBN?
- Do you really need the Japanese Waterstone to get a mirror finish?
- How does honing change the finish?