Cleveland C70355 Screw Machine Drill Bit 51 Hss

Product Description

The CLEVELAND C70355 is a screw machine length drill bit in wire size 51, designed for high-production drilling in tight-tolerance applications. Built from high-speed steel with a bright uncoated finish, it features a 135-degree split point that reduces walking and lowers thrust on entry. The web-thinned, parallel-web construction supports cleaner hole starts and consistent chip evacuation through two spiral flutes. With an overall length of 1-11/16 inches and a straight cylindrical shank, this bit suits screw machines, drill presses, and CNC equipment where compact tooling is required. Machinists and tool-and-die technicians are the primary users.

This bit is sized at 0.0670 inches in diameter and is suited for drilling alloy steel and aluminum in production environments. Its screw machine length profile — shorter than a jobber bit — provides added rigidity, which reduces deflection when boring small-diameter holes in metalworking applications. The 11/16-inch flute length and 1-inch shank length are optimized for shallow-to-moderate depth holes typical in screw machine work and precision machining. The bit meets ASME B94.11M dimensional standards and carries NAS 907 Type C specification designation.

Key Features

• 135-degree split point reduces drill walking and lowers entry thrust
• Web-thinned parallel web improves chip flow and reduces cutting resistance
• High-speed steel construction rated for heavy-duty grade service
• Screw machine length body provides greater rigidity than jobber-length bits
• Diameter tolerance held to +0.0000 to -0.0005 inches for precision fitment
• Compliant with ASME B94.11M and NAS 907 Type C specifications

Compatibility

Designed as an OEM-style replacement or production-use drill bit for screw machines, CNC lathes, drill presses, and similar equipment requiring wire-gauge tooling in the 0.0000 to 0.1000 inch diameter range. Suitable for primary workpiece materials including alloy steel and aluminum.

Installation Notes

Installation and use of this bit should be performed by a qualified machinist familiar with small-diameter tooling. Ensure the spindle and chuck are clean and free of debris before seating the straight cylindrical shank to prevent runout. Do not exceed the recommended RPM for the workpiece material and bit diameter, as small-diameter HSS bits are susceptible to breakage under excessive feed rates or lateral loading. Coolant-through is not supported on this bit; apply external cutting fluid as appropriate for the workpiece material.