Sharpening Tools & Materials

What sorts of sharpening tools and abrasives do you need? Should you sharpen by hand or use a sharpening machine? That depends on the tools you need to sharpen, your experience, and your preferences.

HAND SHARPENING TOOLS

Bench Stones

A set of whetstones or bench stones is the core of most sharpening systems. These are available in different sizes, shapes, and grits. The materials are either natural stone or synthetic abrasives in a hard binder. Many stones are used with light oil or water. The liquid cleans the surfaces, floating away the swarf (metal particles) so it won’t clog the abrasives. On sharpening machines, liquids also serve as a coolant, keeping the tool steel from overheating and losing some of its hardness.

Sharpening stones come in a variety of shapes and sizes to conform to the cutting edges of different tools. They also come in a variety of grits, from 100# to 1200#, so you can hone keener and keener edges, as needed.

Mythconceptions

ANTI-LUBRICANTS -- Liquids used to clean bench stones are traditionally referred to as lubricants, but this is misleading. A true lubricant reduces friction and abrasion, but you need to abrade the metal to sharpen a tool. These liquids clean and cool; they don’t lubricate.

Files

Many woodworking tools, especially hand saws and drill bits, are designed to be sharpened with files. Although made of steel, files are hardened to a higher degree than wood cutting tools. Consequently, they will cut away the worn surfaces of a cutting edge.

Files come in a variety of sizes and shapes, some of them specially made for sharpening. Sharpening files tend to be single-cut with a fine tooth pattern. They may also have safe edges or faces – surfaces without teeth. An auger file, for example has one end with safe faces and the other with safe edges. This can be absolutely indispensible when you want to sharpen a cutting surface without changing the shape of those surfaces adjacent to it.

Several types of files are useful for sharpening. Three-square files are made to fit saw teeth, while round files will fit hook teeth and chain saw teeth. You must have an auger file to sharpen drill bits. Needle files are handy for sharpening cutting edges with intricate shapes, and mill files are handy for flat, straight cutting edges.

Strops

Strops are hard, flat, porous surfaces that can be loaded with ultrafine abrasives to polish cutting edges to a fine point. These abrasives include:

Silicon-carbide powders such as valve-grinding compound.
Natural buffing compounds like emery, Tripoli, or jeweler’s rouge.
Synthetic polishing compounds like chromium oxide.

Traditionally, strops are made form smooth leather and backed with wood or plywood. However, you can use any surface that is slightly porous. Parchment and paper both make excellent strops provided they are applied to stiff, flat material.

The strop shown was made by applying a smooth piece of pig leather to a plywood board with contact adhesive. When "loading" the leather with abrasives, you only need apply a very small amount -- sort of like coloring lightly with a crayon.

Material	Cleaner	Preparation/Care	Characteristics	Grit (#)	Color
Arkansas Stones	Light oil or water	Soak in cleaner prior to using first time. Wipe away dirty oil or water after each use; cover stone to keep from drying out; scrub clean with oil, kerosene, or soap and water.	Long wearing; produce an extremely keen edge; oil cleaner may contaminate wood surfaces if tools aren't wiped clean after sharpening.	Washita (350#)	Multicolored
				Soft Arkansas (500#)	Gray-green
				Hard White (700#)	White
				Hard Black (900#)	Black
Synthetic Oilstones	Light oil	No preparation required; impregnated with oil. Wipe away dirty oil after each use; scrub clean with oil or kerosene.	Extremely hard and long-wearing; inexpensive; produce serviceable edge but not extremely keen; oil cleaner may contaminate wood surfaces if tools aren't wiped clean after sharpening.	Coarse India (100#)	Brown or tan
				Coarse Crystolon (100#)	Gray or black
				Medium Crystolon (180#)	Gray or black
				Medium India (240#)	Brown or tan
				Fine India (280#)	Brown or tan
				Fine Crystolon (280#)	Gray or black
Waterstones	Water	Soak coarse and medium stones in water prior to using; fine stones need no preparation. Rinse stones after each use. If stones are stored submerged, change water occasionally and keep from freezing.	Many grades available; fast cutting but wears quickly; clay binder erodes constantly revealing new grit; produces extremely keen edge. Water may rust tools if steel isn't wiped dry after sharpening.	250 Extra Coarse (180#)	Tan, brown, or gray
				800 Coarse (400#)	Tan, brown, or gray
				1000 Medium Coarse (500#)	Tan, brown, or gray
				1200 Medium (600#)	Tan, brown, or gray
				4000 Fine (900#)	Tan, brown, or gray
				6000 Extra Fine (1000#)	Tan, brown, or gray
				8000 Ultrafine (1200#)	Tan, brown, or gray
Diamond Stones	None required	No preparation required. Brush away filings as you work; wipe occasionally with a damp cloth. Scrub clean with fiberglass pad and soap.	Extremely long wearing; produce fairly keen edge; can be used to sharpen carbide tools; very expensive.	Coarse (240#)	Silver-gray
				Medium (320#)	Silver-gray
				Fine (600#)	Silver-gray
				Extra Fine (1200#)	Silver-gray
Ceramic Stones	None required	No preparation required. Wipe occasionally with a damp cloth. Scrub clean with fiberglass pad and soap.	Extremely long wearing; produce extremely keen edge; no coarse grits available; can be used to sharpen carbide tools; moderately expensive.	Medium (600#)	Gray
				Fine (1000#)	White
				Ultrafine (1200#)	White