The cordless 125 mm angle grinder. Its motor and electronics sit in a sealed housing, which on a tool that lives in mineral dust is the specification that decides how long it lasts. Speed varies from about 4,500 to 8,500 rpm, so cutting and grinding can each be run at a sensible rate rather than everything at full. The motor is decoupled from the housing to cut vibration, and the spindle locks with a quick-action nut so discs change without a spanner.
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