Start by matching the task to disc size, power, and expected duty. For light-duty work such as deburring or small cuts, choose a compact 115–125 mm grinder with about 900–1200 watts and a no-load speed near 11,000–12,000 RPM. For heavy-duty cutting, grinding, and surface prep on steel or concrete, opt for a 230 mm grinder with around 2600–3000 watts and a no-load speed around 6,600 RPM. Check compatibility: most units use an M14 spindle with 22 mm disc bore and support 115–230 mm discs. Weight varies from roughly 3 kg to over 6 kg depending on model.?