Cleveland C71284 Jobber Length Drill Bit 7.9 Mm Hss

Product Description

The CLEVELAND C71284 is a jobber-length twist drill bit engineered for general-purpose drilling in metal, wood, and plastic. Built from high speed steel with an oxide finish, the bit operates with a 118-degree standard point angle and a right-hand spiral flute that clears chips efficiently during through-hole and blind-hole operations. The shank diameter matches the drill diameter at 0.311 inches, allowing it to seat directly in standard three-jaw chucks. At 4.606 inches overall length with a 2.953-inch flute, it delivers the reach and chip clearance typical of jobber-series tooling. Suitable for both handheld drill drivers and drill press setups across a wide range of trade applications.

This drill bit is sized at 7.9 mm (0.311 inches) and falls within the DIN 338 specification, making it a standard metric size used in mechanical, HVAC sheet metal, plumbing rough-in, and electrical panel work where metric fastener clearance holes are required. The web-thinned, tapered web design reduces cutting force at drill entry, which is particularly useful when working on thinner-gauge steel or structural members without a pilot hole.

Key Features

• 7.9 mm (0.311 inches) diameter with a diameter tolerance of -0.001 to 0.000 inches for consistent hole sizing
• 118-degree standard point angle with web-thinned, tapered web for reduced entry force
• High speed steel construction with oxide coating for corrosion resistance and basic lubrication
• Right-hand regular spiral flute for positive chip ejection in general-purpose materials
• Straight-cylindrical shank at 0.311 inches fits standard drill chucks without adapters
• Conforms to ASME B94.11M and DIN 338 standards

Compatibility

Designed as a general-purpose jobber-length drill bit compatible with any standard three-jaw chuck accepting a straight-cylindrical shank up to 0.311 inches. Fits bench drill presses, magnetic drill units, and handheld drill drivers used in HVAC, plumbing, and electrical trade work.

Installation Notes

Secure the shank fully in the chuck and verify concentricity before drilling to avoid bit walk. Power down the drill press or unplug the handheld tool before changing bits. Use cutting fluid or light oil when drilling steel to extend bit life and maintain hole tolerance. Wear appropriate eye protection; chip ejection from spiral flutes can project material at high velocity.