Metric Ratchet Hex Wrench Single Double End Fast Repair Tools 3mm - 17mm

Single End wrenches have one hex tip and are suited when you work exclusively with one bolt size. Double End wrenches have two hex tips on opposing ends — for example, a 3mm tip on one side and a 5mm tip on the other — so you can switch between two sizes without swapping tools. Double End variants are more versatile for mixed-fastener jobs.

Measure the width across the flats of the socket-head bolt recess, or check the bolt's specification sheet. Common pairings: M3 bolts typically use a 2.5mm hex key; M4 uses 3mm; M5 uses 4mm; M6 uses 5mm; M8 uses 6mm; M10 uses 8mm; M12 uses 10mm. When in doubt, test-fit before applying torque to avoid rounding the recess.

The Cr-V steel construction supports sustained torque for typical assembly and maintenance tasks. However, ratchet hex wrenches are not designed to replace torque wrenches for safety-critical fasteners (e.g., engine head bolts, suspension components). For those applications, use a calibrated torque wrench. For furniture, cycling, and general machinery maintenance, this wrench provides adequate torque capacity.

Cr-V steel is harder than standard carbon steel and performs well against most stainless steel socket-head fasteners (A2/304 grade). For Grade 12.9 or hardened alloy fasteners, ensure you apply steady, controlled force to avoid slipping. If the fastener is heavily corroded or seized, apply penetrating oil first to reduce the required breakaway torque.

The ratchet head engages in one rotational direction (tightening or loosening, depending on the switch setting) and freewheels in the opposite direction. This means you only need a small arc of rotation — as little as a few degrees — to advance the fastener, making it practical in spaces where a full 360° swing is impossible. Reverse the ratchet direction to switch between tightening and loosening.

Wipe the hex tips and ratchet head clean after use to remove metal filings and debris. Periodically apply a small drop of light machine oil to the ratchet mechanism to keep it operating smoothly. Store in a dry location to preserve the surface finish. Avoid using the wrench as a pry bar or hammer, as this can damage the ratchet internals.

Yes. Simply set the ratchet direction to the loosening mode and use it to tighten a left-hand threaded fastener, or vice versa. The hex tip itself is direction-neutral — only the ratchet direction setting changes the effective drive direction.