Cleveland C70090 Jobber Drill Bit 4.3 Mm Cobalt

Product Description

The CLEVELAND C70090 is a jobber-length drill bit designed for precision hole-making in metal fabrication, maintenance, and light industrial applications. Built from M42 cobalt high-speed steel and finished with a gold oxide coating, the C70090 offers improved heat resistance and extended tool life compared to standard HSS bits. It features a 135-degree split point that reduces walking on entry and lowers thrust requirements at the start of the cut. The straight-cylindrical shank measures 0.1693 inches in diameter and seats securely in standard drill chucks. This is a heavy-duty grade bit rated to NAS 907 Type J specification.

The C70090 is suited for drilling aluminum and other non-ferrous and ferrous materials in shop and field settings. With a 4.3 mm (0.1693 inch) cutting diameter and an overall length of 3.15 inches, it fits standard jobber-length applications on drill presses, cordless drills, and hand-held electric drills. The two-flute spiral design provides efficient chip evacuation during through-hole drilling. Machinists, millwrights, and maintenance technicians commonly reach for this bit when working within the 4.00 mm to 5.00 mm diameter range.

Key Features

• M42 cobalt steel construction for elevated heat resistance and wear life
• 135-degree split point reduces drill walk and lowers entry thrust
• Gold oxide coating helps resist galling and extends coating durability
• Web-thinned tapered web improves chip flow and reduces cutting torque
• NAS 907 Type J specification compliance for consistent dimensional accuracy
• Right-hand cut, regular spiral for standard through-hole drilling operations

Compatibility

Designed as a jobber-length replacement drill bit for use in standard straight-shank drill chucks across drill presses, handheld electric drills, and CNC drilling fixtures requiring a 4.3 mm diameter bit in the 4.00 mm to 5.00 mm size range. Primary workpiece material is aluminum per specification, though the M42 cobalt grade is also applicable to harder materials at appropriate feed and speed settings.

Installation Notes

Secure the straight-cylindrical shank fully into the drill chuck and tighten with a chuck key before operation. Confirm spindle speed is appropriate for the workpiece material and bit diameter before starting the cut. Always wear appropriate eye protection and ensure the workpiece is clamped or fixtured to prevent rotation. Do not use excessive feed pressure on entry, as the split point geometry is designed to self-center at moderate thrust loads.