With a bench grinder you can reshape and sharpen all your cutting tools easily and quickly. With woodturning tools, axes, shears and the like you can go straight back to work. For chisels, plane blades, shop knives and other precision cutting tools you’ll still need to do final honing with bench stones or another method. Conventional bench grinders have two arbors and are sized to accommodate 6″, 8″ or 10″ wheels. Some come with two grinding wheels; usually a 36-grit and 60- or 120-grit. Others come with a single grinding wheel and a wire wheel. A range of different wheels are available and they’re easy to install. The newer cubic boron nitride (CBN) wheels remove material much more quickly, last a lot longer, remain flat (so they don’t need dressing like other wheels) and run much cooler. High-speed conventional grinders run at 3,600 RPM. Low-speed conventional grinders run at 1,750 RPM and are much less likely to overheat a tool edge. Horizontal disc and wet/dry slow-speed grinders are specifically designed for the needs of hand tool users.
Price: Conventional grinders, $75 to $350; horizontal grinders, $320 to $550; wet/dry low-speed grinders, $380 to $1,000
Power source: 110V AC
Motor size: 2.1 amps to 1-1/2 HP
Speeds: 1,750 to 3,600 RPM
Wheel size: 6″, 8″, 10″
Wheel grit: 36 and 60 or 120-grit, silicon-carbide or aluminum oxide (preferred)
Bench grinders tend to vibrate in use. You’ll do a better grinding job by bolting or clamping the grinder to a stable surface.
Metal heats up rapidly and can quickly compromise the temper of a chisel or plane blade. Grind slowly and quench in water frequently.
Keep the item you’re grinding moving smoothly across the width of the wheel. And remember to quench.
The tool rests that come with most grinders are usually small, flimsy and difficult to adjust. If you do a lot of grinding (especially with chisels and plane blades) purchase a commercial stand-alone tool rest.
Over time, wheels become clogged with grit, causing them to remove metal less efficiently and to overheat your tools. They also wear so they’re not straight. Use a wheel dresser regularly to keep the wheels in prime grinding condition.