Hex Key Bondhus BO13849 — 1.27 mm, 42 mm length, precision Allen wrench

Bondhus BO13849 is a precision 1.27 mm hex key (Allen wrench) with a 42 mm overall length designed for reliable engagement with small hex fasteners. Manufactured to tight tolerances, this compact tool provides a consistent fit that helps reduce rounding of fastener heads and enables accurate fastening and adjustment in confined spaces. Its size and construction make it suitable for work on electronics, instrumentation, precision assemblies and hobby projects where small, repeatable torque application is required.

Advantages

The 1.27 mm tip dimension ensures accurate contact with micro hex sockets and minimizes slippage. The 42 mm overall length gives sufficient reach for shallow recesses while remaining short enough for access in tight assemblies. Consistent manufacturing tolerances provide reliable engagement and reduce wear on both the tool and fastener. The compact profile allows precise control during delicate adjustments and small-scale assembly or repair tasks.

Suitable for

• Electronics assembly and repair
• Instrument calibration and maintenance
• RC models, drones and hobby electronics
• Small appliance and precision mechanical repairs

Key specifications

• Tip size: 1.27 mm hex
• Overall length: 42 mm
• Tool type: precision hex key (Allen wrench)
• Intended use: engagement with small hex fasteners in tight spaces

How to use

Select the 1.27 mm hex key and align the tip squarely with the fastener socket to avoid angular loading. Insert the tool fully into the fastener recess for maximum contact area, then apply steady torque in a controlled manner. For tightening, turn clockwise until the required clamping is achieved; for loosening, turn counterclockwise. When working in confined areas, use the short length to maintain control and prevent over-rotation. Inspect both tool and fastener for wear before use and replace the key if the tip shows rounding.

Usage recommendations

Use the hex key for low to moderate torque tasks appropriate to a 1.27 mm driver. Do not apply excessive force or use the tool as a lever or pry bar. Store in a protective case or tool holder to preserve tip geometry and ensure long service life.