1x4 Sigma 10K Select II

The 1x4 Sigma Select II 10K Grit stone is the second polishing stone in the Sigma Select II series, bringing out a smooth slicing edge in the region of hair whittling and air popping sharp. The smoothly polished mirror cutting edge turns your edge in to a superior knife or tool. This stone is best used after a finer medium grit and/or a lower polishing grit (3K-8K) stone to really bring out hair shaving sharpness and full mirror shine, and to prepare the edge for higher polishing grits and stropping.

This stone is 1" x 4" in size mounted to an aluminum blank with a total thickness of 5-6mm and used with water only. It works best when soaked in water for a minute or two before use. Let air dry and store dry when not in use.

Abrasive Material: Aluminum Oxide

Ideal place in a sharpening progression:

• Starting grit for light touching up of an intact edge.
• After higher medium grit and lower polishing grit sharpening stones (3K, 4K, 5K, 6K, 8K grit)
• Before progressing to further polishing stones and strops (12K+, 1 micron - 0.025 micron strops)
• A final stone for full mirror polished sharpness on many knives and tools.

The 10K Sigma sharpening stone is a premium sharpening stone that works on almost all types of knives, scissors, tools and chisels, including those made with abrasion resistant steels. While the 1x4 size is meant for use with the KME Sharpener, it is also a great size for a slip stone, field stone or a pocket stone for knife repairs and sharpening on the go, or to remove unwanted burrs. 

On More Traditional Carbon Steel and Stainless Steel Edges, the Sigma Select II 10K stone works on steels between RC 52 and RC 65 on the Rockwell C Hardness scale. On softer end stainless steels used by many kitchen knife makers like Henckels, Wüsthof, Gunter Wilhelm, F Dick, Victorinox, etc. such as X50CrMoV15, AUS6, 440B, this 10K stone leaves a highly polished slicing edge. On these steel types, this stone can maintain a serviceable edge, but does require a lower grit stone for any real damage or change in profile. Also, the structural characteristics of the steel may get close to reaching its upper limits at this grit.

On the higher end of the hardness spectrum of traditional steel edges made with steels like 1095, 52100, 440C, Aogami White, Shirogami Blue, O1, W1, etc. The Sigma Select II 10K establishes a full on mirror finish with a smooth slicing edge. It can be used as a stand-alone stone to maintain the sharpness, but will require a coarser grit stone to do more serious repairs or profiling. The edges one these harder steel types thrive in this higher grit atmosphere, and the 10K is a very enviable final grit, or just the beginning of the journey to finer stones and stropping.

On Carbide Forming Steel and More Abrasion Resistant Steel Edges such as VG-10, D2, M2, S35V, S90V, etc., The Sigma 10K stone is a pure polishing stone and requires a properly prepped edge from lower grits in order to bring out the maximum potential of the shine. While the full mirror effect will depend on the progression before the 10K, the sharpness will continue to improve as the matrix steel is abraded. The edge off this stone can be used as is, or to be further refined with stropping or finer grits stones.

Hacks and Tips:

• Use a moderate amount of water when sharpening with this stone to avoid the black swarf from turning into a thick paste. A cleaner surface will cut faster than a thicker pasted one.
• If using this stone as a final or polishing grit, keep the black swarf viscous and it will produce a slightly more refined edge.
• Lap this stone with a medium diamond plate, silicon carbide (SiC) powder, or 220-400 grit wet dry sand paper to keep it consistently flat and clean.

Comparable Stones: Naniwa Chosera 10K, Suehiro 10K Gokumyo