Power Sharpening

A slow-speed grinder typically runs at around 1,725 RPM compared to 3,450 RPM for a standard grinder. The lower speed generates significantly less heat, which prevents drawing the temper out of high-speed steel chisels and plane irons. For woodworking tools, a slow-speed grinder is strongly preferred.

Carbide router bits require diamond abrasives to sharpen effectively. The Work Sharp Ken Onion Edition can work with certain diamond belt attachments, but for dedicated router bit sharpening, a diamond hone is often more practical. See the sharpening collection for diamond hones and cross-sharpener options designed specifically for carbide edges.

Jointer knives can be sharpened on a slow-speed grinder using a tool rest or a dedicated jig that maintains the correct bevel angle. The Rikon 8" Slow Speed Grinder is a common choice for this task. A diamond knife hone can then be used for touch-ups without removing the knives from the machine.

Power grinding is typically reserved for regrinding a bevel after the edge has been significantly damaged or rolled, or when establishing a new bevel angle. Day-to-day maintenance is done with honing stones or strops, which remove very little metal and keep the edge sharp between grindings.

A common progression starts with a coarse belt (e.g., 80 or 120 grit) to establish or repair the bevel, moves to a medium belt (220 grit) to refine it, and finishes with a fine belt (6000 grit leather strop equivalent) to polish the edge. The Work Sharp Replacement Belt sets are available in various grits for this progression.

A combination belt and disk sander like the Rikon 4x36 Belt & 6" Disk Sander can flatten and sharpen the back of chisels and plane irons efficiently when used with fine-grit belts. It is best used as a coarse flattening step before moving to dedicated sharpening stones.

Belt-driven sharpeners like the Work Sharp Ken Onion Edition handle curved profiles reasonably well using the flexible belt. Slip stones and power stropping wheels are also common for inside bevels on gouges. The right tool depends on the sweep and size of the gouge.

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CBN (cubic boron nitride) wheels run cooler, stay flat longer, and cut faster than conventional aluminum oxide grinding wheels. They are a worthwhile upgrade for woodworkers who sharpen frequently, though the initial cost is higher. Aluminum oxide wheels are fine for occasional use.

Infinity Tools publishes technique articles on sharpening and tool setup at the Learn blog. Articles cover bevel angles for bench chisels, plane irons, and turning tools, along with practical tips for getting consistent results from motorized sharpening systems.