Open End Wrenches 13mm-90mm High Carbon Steel Heavy Spanner Repair Workshop Tool

Measure across the flats of the hex fastener (bolt head or nut) with a caliper or ruler. The measurement in millimeters corresponds directly to the wrench size you need. For example, a fastener measuring 19 mm across the flats requires the 19 mm wrench. When in doubt, size up — a wrench that is too small will not fit, while one that is slightly too large will slip.

High carbon steel offers excellent hardness and tensile strength, making it well-suited for heavy-duty, high-torque applications. Chrome vanadium (Cr-V) adds corrosion resistance and slightly greater toughness under impact. For workshop and repair use where the wrench is stored indoors and used with deliberate force rather than impact, high carbon steel performs reliably and holds its shape under load.

Yes. The smaller sizes (14 mm – 24 mm) cover the majority of automotive fasteners found on engine mounts, suspension components, brake calipers, and exhaust systems. The open-end jaw design is particularly useful in tight engine bays where a socket and ratchet cannot reach. For very high-torque applications such as axle nuts, pair the wrench with a breaker bar extension if needed.

Always select the exact matching size — never use a wrench that is even 1 mm too large. Position the jaw fully onto the fastener flats before applying force. Pull rather than push the wrench when possible, and apply steady, controlled torque rather than sudden jerks. If a fastener is corroded, apply penetrating oil and allow it to soak before attempting removal.

High carbon steel has moderate corrosion resistance. To extend service life, wipe the wrench clean after each use and apply a light coat of machine oil or tool lubricant before storage. Avoid leaving the tool in wet or high-humidity environments for extended periods. For outdoor or marine applications where corrosion is a primary concern, consider stainless steel alternatives.

Yes. The larger sizes (27 mm – 90 mm) are commonly used on hex-body pipe fittings, union nuts, and HVAC service valves. The open-end design allows the wrench to engage fittings that are close to a wall or another pipe where a box-end wrench would not clear. Always confirm the fitting's hex size before ordering.

Each listing is for one (1) wrench in the size you select. This allows you to purchase only the specific sizes you need rather than paying for a full set that includes sizes you may never use. If you need multiple sizes, simply add each size to your cart separately.