1x4 Sigma 6K Select II

The 1x4 Sigma Select II 6K Grit stone is the first stone to impart a mirror finish in the Sigma Select II series. The edge is a practical mix of sharp, smooth and shiny and is very suitable for most knives and tools, and is the foundation polish stone for further refinement through stones or strops and emulsions.

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 repair and maintenance of an already sharpened but dull edge.
• After medium grit sharpening stones (1K - 4K grit)
• After finer belt grinder grits (A6 Trizact grit)
• Before progressing to further polishing stones (8K - 16K grit)
• Before finishing on leather, kangaroo, and nanocloth strops and emulsions.
• A final stone for mirror polished sharpness on many knives and tools.

The Sigma Select II 6K 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 6K 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 5K stone leaves a highly polished edge that is more suited to slicing. On these steel types, 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 6K establishes a full on mirrored slicing edge. It can be used to maintain the sharpness, but will require a coarser grit stone to do more serious repairs or profiling. These harder steel types thrive in this higher grit atmosphere, and 6K can be a versatile 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 Select II 6K 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. The cutting edge off the 6K is more slicing, but the carbides still give the edge some stiffness and bite. 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 220-320 grit wet dry sand paper to keep it consistently flat and clean.

Comparable Stones: Jende 6K SPK