The Best Bench Grinder for Wood Turning

Lathe Tools

• Lathe tools range in thickness from 1/8 inch to more than 1/4 inch, with either straight or curved cutting edges. Turning tools made to slice through wood are ground with acute bevels, while turning tools designed to scrape fine shavings from wood use edges ground nearly perpendicular to the blade. High-speed bench grinders shape lathe tools quickly, but lingering a second too long overheats the edge of the tool. When a tool tip burns, the tool won't cut well until you grind away the burned section and successfully shape a new cutting edge. Grinders should shape tools efficiently without wasting steel.

Grinder Speed

• The acute edge of a lathe cutting tool such as a spindle gouge or skew chisel overheats easily. Many bench grinders turn at 3,450 rpm, allowing fast stock removal with a smaller and safer grinding wheel. At lower speeds, you can sharpen turning tools with better control. Adjustable-speed grinders provide stable power over a continuous range from 3,450 rpm to 1,725 rpm. Select the lowest speed for sharpening cutting tools and scrapers, and use high speeds for reworking damaged edges.

Wheel Diameter

• Grinding wheels with larger diameters cut shallower concave bevels and make subtle improvements in cutting action. The shallow curve leaves slightly more steel behind the cutting edge and increases the strength of acutely beveled tools. Less expensive bench grinders accept wheels of only 6 inches in diameter. Larger machines designed for home workshops accept 8-inch diameter wheels. A larger wheel's surface moves faster and heats the tool quicker than a small wheel, so speed control becomes more important with a larger bench grinder. Larger wheels also increase hazards if mounted improperly, or if run when out of balance.

Wheel Grit

• Neither the coarse-grit nor medium-grit grinding wheels usually supplied with bench grinders suit the needs of the wood turner. Both create cutting edges that leave scoring marks on the workpiece. Fine-grit wheels grind a cutting edge good enough for shaping a workpiece without honing. A tool ground with a fine-grit wheel needs only a little touch-up with a honing slip to produce a nearly flawless final surface on the wood turning. Aluminum-oxide grinding wheels wear away in use, constantly exposing a new grinding surface and preventing clogging. Aluminum oxide wheels become unbalanced due to uneven wear and require frequent truing with a wheel dresser.