Screwdriver bit set KWB 128640 — 3 pcs, Robertson tips, 28 mm length

KWB 128640 screwdriver bit set includes three 28 mm Robertson (square) bits intended for use with manual screwdrivers, power drivers and bit holders. These micro bits are engineered for small square-drive screw connections, offering a balance of compact size and reach for tasks in carpentry, furniture assembly, electrical work and maintenance of older vehicles. Manufactured from high-quality TQ 60 steel with a satin finish, the bits are mounted on a practical fastening strip and have a 4 mm hexagon shank compatible with standard bit holders.

Advantages

The set provides precise engagement with Robertson screws thanks to accurately formed square tips, reducing cam-out and slippage. The 28 mm extra length enables access to recessed or hard-to-reach fasteners while retaining control in confined spaces. TQ 60 steel construction ensures strength and wear resistance appropriate for frequent use, and the satin surface finish minimizes glare and corrosion. The 4 mm hex shank offers broad compatibility with common bit holders and drivers.

Suitable for

• Carpentry and woodworking where square-drive screws are used
• Furniture assembly and fittings installation
• Electrical and electronic maintenance with small screw connections
• Restoration and repair of vintage cars and machinery
• General household maintenance and DIY tasks

Key specifications

• Tip type: Robertson (square) drive
• Quantity: 3 bits per set
• Bit length: 28 mm (extra long for micro bits)
• Material: TQ 60 steel
• Shank: 4 mm hexagon
• Surface: satin finish
• Mounting: practical fastening strip

How to use

Select the appropriate Robertson bit from the fastening strip and insert the 4 mm hex shank into a compatible bit holder or driver chuck until it seats securely. Align the square tip with the screw recess and apply steady axial pressure while turning the driver. For power drivers, use low to medium torque settings for small screws to prevent overdriving or damaging the fastener. After use, return bits to the fastening strip for organized storage and to protect the tips.

Usage recommendations

Use with drivers or bit holders that accept a 4 mm hex shank and set torque limits on powered tools when working with small or delicate screws. Inspect tips periodically for wear and replace the bit if tip deformation or rounding is observed to maintain secure engagement with square-drive screws.