HSS Spiral Fluted Step Drill Bit 4mm 39mm

This comprehensive 13-step heavy-duty variant spans from 4mm to 39mm in 3mm increments, making it the ultimate solution for large-diameter hole requirements in HVAC installations, industrial metalwork, and ducting applications. The extended 107mm overall length provides excellent reach and stability, whilst the robust 315g construction delivers the rigidity needed for drilling larger apertures without deflection. Engineered for high accuracy drilling in sheet materials, this professional-grade step drill bit handles substantial hole sizes with confidence. The 3mm step increments cover the most commonly required diameters for ventilation grilles, large cable entries, and industrial pipe penetrations, significantly reducing the number of tools required on site.

Features and Benefits:

• HSS steel construction for maximum durability in heavy-use environments
• Spiral fluted design ensures efficient chip removal even at larger diameters
• Cylindrical shank with 3 flats provides secure drive and prevents micro-locking
• Laser-marked diameter graduations in groove remain visible throughout tool life
• Extended step range eliminates need for multiple large drill bits

Specifications: Steps [mm]: 4 - 6 - 9 - 12 - 15 - 18 - 21 - 24 - 27 - 30 - 33 - 36 - 39 Overall Length: 107mm Weight: 315g