Cleveland C70278 31/64 Inch Hss Screw Machine Drill Bit

Product Description

The CLEVELAND C70278 is a screw machine length drill bit designed for high-production drilling applications where a shorter, more rigid tool reduces deflection and improves hole accuracy. Built from high-speed steel with a bright/uncoated finish, this bit measures 31/64 inches (0.4844 inches decimal) in diameter with a 3-11/16 inch overall length and a 2-3/16 inch flute length. The 135-degree split point geometry initiates cutting immediately without a center punch, reducing walking on entry. Web thinning further lowers thrust requirements, making it well suited for drilling alloy steels and aluminum in production environments.

Screw machine length drill bits are commonly used in machine shop and production settings where drill press, CNC, or turret lathe setups benefit from the reduced overhang of a stubby geometry. This bit is appropriate for hand-held drilling in tight quarters as well, where a jobber-length bit would be impractical. The straight cylindrical shank fits standard drill chucks without modification. Primary workpiece materials include alloy steel and aluminum. The heavy-duty grade designation indicates this bit is built for repeated use under sustained cutting loads rather than occasional light-duty applications.

Key Features

• 135-degree split point eliminates center-punch step and reduces entry walking
• Web-thinned, parallel web configuration lowers axial thrust for cleaner entry
• High-speed steel construction provides heat resistance in sustained cutting cycles
• Screw machine length body increases rigidity and reduces deflection compared to jobber length
• Right-hand cut with regular spiral flutes for standard chip evacuation
• Meets ASME B94.11M and NAS 907 Type C specifications

Compatibility

Designed as an OEM-style replacement or direct-use screw machine drill bit for standard 3-jaw drill chucks and collet systems accepting a 0.4844-inch straight cylindrical shank, consistent with ASME B94.11M and NAS 907 Type C tooling standards.

Installation Notes

Installation and use of this drill bit should be performed by machinists or qualified trade professionals familiar with proper chuck torque and speed-and-feed selection for the workpiece material. Ensure the drill press, lathe turret, or hand drill is fully powered down and the chuck is secured before loading the bit. Follow applicable shop safety codes and manufacturer speed-feed charts for high-speed steel tooling when drilling alloy steel or aluminum. Do not exceed the rated cutting parameters for the tool grade, as overheating without coolant will reduce tool life.