The Sharpening Center Presents:
"How To Put The Best Edge On Tooling With Norton Industrial Sharpening Stones"
Please Note: The following text is reprinted from Norton Company literature and reflects their instructions for using their products. The KnifeCenter offers these instructions for informational purposes only with no guarantees as to their effectiveness.
From Norton, producers of fine sharpening products (see them HERE)
Get top performance and productivity from tooling - put on the final finish with the right sharpening stone.
Sharpening Stone Selection
To get top performance and productivity from tools and dies, the final finish requires the right sharpening stone. If a stone is too hard for the job, you'll never get the desired edge regardless of how hard you work. If too soft, you can't control the amount of material taken off the tool. If not oil filled, the lubricating oil will drain out the bottom, permitting metal particles to glaze the surface and render the stone useless. Hence, the selection of the proper sharpening stone for the job is essential.
Norton manufactures the world's most comprehensive line of sharpening stones. Included are bench stones for straight-edged tools; a broad range of abrasive files for finishing, chamfering, deburring and fitting delicate parts; slips for curved-edge tools and knives; and a wide selection of specialty stones and rubbing bricks to fill nearly every need.
Norton sharpening stones are available in three different abrasives- Crystolon®, India® and Arkansas — each designed to meet specific needs.
- Crystolon stones are made of silicon carbide electric-furnace abrasive, gray or black in color. This fast-cutting abrasive is harder than any natural abrasive except diamond, and does an outstanding job finishing carbide tools or removing metal, when moderate tolerances are acceptable. Crystolon is the choice where speed of sharpening is most important, or as the first step in sharpening badly worn cutting edges. Available in coarse, medium and fine grits.
- India stones are made of aluminum oxide electric furnace abrasive, brown or orange in color. This abrasive is preferred for producing exceptionally keen, long-lasting edges, and for high-quality steel tool work. The choice over Crystolon where close tolerances and smooth cutting edges are required. Available in coarse, medium and fine grits.
- Arkansas natural abrassive stones are made of Novaculite, white to black in color. Hard Arkansas (ultra fine grit), with its very dense, close construction, is recommended for final honing where the sharpest precision edges possible are needed. Soft Arkansas (super fine grit), with its less dense and more open construction, is ideal for producing final finishes after prior sharpening with electric furnace abrasives.
Norton sharpening stones are manufactured in five basic grits, to handle the complete range of sharpening needs.
- Coarse grit is recommended for basic restoring of a badly worn cutting edge and for all sharpening not requiring a keen edge.
- Medium grit is recommended for producing an average edge on a broad range of tools, including jointer devices, skiving knives, craving tools, milling cutters, lathe tools and die chasers.
- Fine grit is recommended for producing a sharper-than-average edge on woodworking tools, gouges, reamers, taps, auger bits and twist drills.
- Super Fine grit is recommended for fine edges used in finishing, such as plane blades, router blades, frisket knives and for honing and polishing dies and molds.
- Ultra Fine grit is recommended for producing the keenest edge possible on precision tools and delicate instruments.
In addition, many bench stones and some specialty items are available as combination stones-two different grit surfaces in one stone. These stones offer complete, economical sharpening in a single instrument.
Lubricate the stone
For efficient sharpening, lubricating the stone with oil is efficient to float away metal and abrasive dust that will otherwise clog up and neutralize the stone. Norton Oil, specially formulated for sharpening stones, makes every stone work better to do a more efficient job.
Most Norton India and Crystolon stones are pre-filled with lubricating oil at the factory-a unique Norton quality feature that lets you put the stone to work right away without pre-soaking. Even with oil pre-filling, be sure to apply lubricant every time the stone is used- it's vital to continued good stone performance.
Factors that add to efficient sharpening
Most manufacturers sharpen tooling during production, but don't put the keenest edge possible to them, to avoid damage in transit and handling. Before a tool is put into service, it should be given a light sharpening to bring out its full potential on the machine. Be sure to keep these factors in mind:
- Take a good, close look. A dull edge, when held to the light, will actually appear shiny. A sharp edge, on the other hand, will not reflect light. By the same token, a dull spot on an otherwise sharpened edge will show up clearly when held to the light. This is an easy way to find and get rid of nicks on edges to be sharpened.
- Maintain the correct tool stone angle. The edge bevel on a tool actually forms the cutting edge, and is the bevel that should be stroked against stone. It should be thin enough to produce a clean chip or shaving, yet thick enough to stand up to the shock of being applied to the workpiece.
- The strength required of the tool back of the cutting edge determines the blade bevel. While the blade bevel may be thin on a tool such as a knife or plane blade, it can also be quite obtuse on a single-point lathe tool or milling cutter. If a tool to be reconditioned has worn back past the edge bevel, the blade bevel may need resharpening (see picture). Always duplicate the original edge and blade bevels. This will maintain the tool at its optimum cutting capability.
- Preserve the tool strength and shape. In sharpening, where metal is removed is very important. For flat blades, sharpening the long side of the edge bevel will leave either a step or long taper in it, and it will weaken the blade significantly. Always sharpen the shortest side of the bevel to preserve the original tool strength.
- Round tools such as taps or reamers should be sharpened in the flutes so as not to disturb the working diameter of the tool. Always consider the angle at which the tool edge meets the work, and use the sharpening stone to preserve it.
- Watch for the wire edge. During sharpening, a wire edge or burr will develop on the edge of the tool being sharpened. This is a sign that the tool has been honed sufficiently. However, the burr is too weak to be of value to the cutting edge, and will actually dull the tool if not properly removed. When the burr comes up, simply turn the tool over and lightly stroke it flat against the stone once or twice to remove the burr. This won't affect the rest of the sharpening job, and will actually produce a more durable edge.
- A clean stone works better. All stones should be oiled before each use, then wiped clean before they're put away. Because dirt and dust can load an oilstone just as much as sharpening dust and metal particles, always keep stones covered and in a clean place between uses.
When stones do need cleaning, use kerosene and scrub with a stiff fiber brush. Then re-soak the stone in oil. If a stone is so badly glazed that brushing doesn't work, rub down the stone surface with 80-120 grit abrasive paper instead, then re-oil. Proper maintenance can extend the life of a sharpening stone or file beyond what might be expected.
Please Note: The preceding text is reprinted from Norton Company literature and reflects their instructions for using their products. The KnifeCenter offers these instructions for informational purposes only with no guarantees as to their effectiveness.