Extra Long Metric Ball Point Hex Key Allen Wrench L-Keys Allan Alan 0.7mm-19mm

A standard hex key requires near-perfect alignment with the fastener axis to engage properly. A ball point hex key has a rounded, spherical tip that allows the tool to engage the socket at an angle — typically up to 25–30° off-axis. This is especially useful when a straight approach is blocked by adjacent parts, panels, or housing walls. The flat (short-arm) end of the L-key retains a standard hex tip for full-torque driving once the fastener is started.

The hex key size must match the across-flats measurement of the socket in your fastener — not the bolt's thread diameter. For example, an M5 socket head cap screw typically uses a 4mm hex key, while an M8 bolt typically uses a 6mm key. If you are unsure, measure the socket opening with a caliper or refer to the fastener manufacturer's specification sheet. When in doubt, start with a slightly smaller key and work up — a key that is too large will not seat, while one that is too small will round the socket.

Extra long hex keys provide two advantages: greater reach into deep or recessed fastener locations, and increased mechanical leverage on the long arm, which can make it easier to break loose tight fasteners. They are particularly valuable in furniture assembly (where bolts sit inside pre-drilled cavities), bicycle maintenance (derailleurs, stem bolts), and machinery servicing where fasteners are surrounded by other components. For everyday surface-level fasteners, a standard-length key is sufficient.

These wrenches are manufactured from hardened alloy steel, which provides good resistance to twisting and rounding under normal DIY and light-to-medium professional torque loads. For the highest-torque industrial applications (such as structural bolting or heavy machinery assembly), always verify that the tool's rated torque capacity meets your requirement. As a general rule, use the flat (non-ball) end of the L-key for final tightening at full torque, and the ball end only for starting or driving at an angle.

The alloy steel construction offers reasonable corrosion resistance for typical workshop environments. To extend service life, wipe the keys clean after use, avoid prolonged exposure to moisture or corrosive chemicals, and store them in a dry location. If you work in a high-humidity or outdoor environment, applying a light coat of machine oil periodically will help protect the surface.

The 7-piece set covers the most commonly used metric hex key sizes in the 1.5–6mm range: 1.5mm, 2.0mm, 2.5mm, 3.0mm, 4.0mm, 5.0mm, and 6.0mm. This range handles the vast majority of everyday fasteners found in furniture, bicycles, electronics enclosures, and general machinery. Sets are available in quantities of 1, 2, 3, 5, and 10 sets, making them practical for both individual use and workshop stocking.

These hex keys are sized in metric millimeters and are designed for metric hex socket fasteners. While some metric sizes are close in dimension to certain SAE sizes (for example, 5mm is close to 3/16"), using a metric key on an imperial fastener — or vice versa — risks rounding the socket. For reliable results, always match the key type (metric or imperial) to the fastener specification.