The angle grinder: the fastest wheel in the shop
A 4-1/2″ angle grinder turns at around 11,000 rpm, which puts its rim speed in the same class as a table saw blade. Unlike the table saw, it has no table, no fence, and nothing between you and the wheel except the guard. It deserves more caution per pound than anything else you own, which is why it comes last in this series.
Machines and tools vary by brand, model, and age. Your manual outranks this page — read it first.
Grinders come into woodshops for good reasons: cleaning up hardware, sharpening lawn tools, and increasingly power carving. The machine itself is sound. It simply leaves very little margin for carelessness in three areas: what is mounted on it, whether the guard is in place, and what the disc is allowed to touch.
Match the wheel to the spindle speed
Every disc carries a maximum rpm, and that number must meet or exceed the grinder's spindle speed. Abrasive wheels also age and crack, so inspect each one before mounting it, and never mount a wheel that has been dropped. A wheel that fails at full speed does not crumble in place; it breaks into pieces that fly outward at the wheel's rim speed.
Keep the guard and the side handle on
Cutoff work adds the same pinch rule you know from the circular saw: a thin wheel bound in a closing cut kicks the grinder hard toward your face or shoulder. Support the work so the cut opens rather than closes, and let the tool reach full speed before it makes contact. Grind on the wheel's face and cut on its edge, never the reverse, because a cutoff wheel loaded sideways snaps. Sparks are a hazard of their own: know where the stream will land before you pull the trigger, and never aim it toward the dust collector, the shavings bin, or the rag shelf.
Chainsaw carving discs: the plain warning
Power carving does not need them. Toothed-ring and burr-style carving discs with limited tooth exposure — the donut-shaped and shrouded designs — remove wood nearly as fast with a fraction of the grab, because they were engineered specifically to avoid the chain disc's behavior. If a project genuinely calls for chain-style stock removal, the right tool is an arborist's chainsaw, which pairs the chain with a chain brake and proper handles. The grinder-disc version keeps the chain and leaves out every one of those protections.
This article closes the series where it started: every machine in the shop supplies the force, and the judgment has to come from you. Keep the guard mounted, check every wheel's rating before it spins, and keep your body out of the wheel's plane. Those three habits cover nearly everything that goes wrong with this tool, and they are all fully under your control.