Variable Speed
Affiliate link — we may earn a commissionVariable speed lets you control the tool's RPM, either with a trigger that responds to finger pressure or a dial that sets a maximum speed. Trigger-based variable speed is standard on drills and impact drivers. You squeeze harder, it goes faster. Dial-based variable speed is common on sanders, routers, and angle grinders. You set the max RPM and the tool holds that speed under load. Some tools have both: a dial sets the ceiling and the trigger controls within that range. Fixed-speed tools run at one RPM and give you no adjustment.
Why It Matters
Different materials need different speeds. Drilling metal requires slower RPM than drilling wood. Sanding a finish coat needs lower OPM than removing paint. Cutting tile with a diamond blade needs slower RPM than cutting steel. Variable speed lets one tool handle multiple materials without overheating or burning the workpiece.