Hertel 04139473 Cobalt Jobber Drill Bit Letter T

Product Description

The HERTEL 04139473 is a cobalt jobber-length drill bit sized to Letter T (0.3580 inches) with a 135-degree split point. It is designed for holemaking in metal and hard materials where a standard high-speed steel bit would wear prematurely. The split-point geometry reduces walking at start and lowers thrust requirements. An oxide and TiN coating provides added surface hardness and lubricity. The straight-cylindrical shank fits standard three-jaw drill chucks. Machinists, toolroom technicians, pipefitters, and maintenance trades use this bit for precision drilling in ferrous and non-ferrous workpieces.

This drill bit is suited for general holemaking operations in steel, stainless, cast iron, and other tough materials in both shop and field environments. The jobber-length flute gives a good balance between reach and rigidity for the Letter T diameter range. The right-hand spiral flute clears chips efficiently during through-hole drilling. It is appropriate for use in drill presses, milling machines, and hand-held electric drills with sufficient chuck capacity for a 0.3580-inch shank.

Key Features

• Letter T size at 0.3580 inches decimal equivalent for precise hole sizing
• 135-degree split point reduces drill walking and lowers feed pressure
• Cobalt construction handles elevated heat generated in hard or abrasive materials
• Oxide and TiN dual coating improves surface hardness and extends tool life
• Web-thinned, tapered web configuration reduces axial load during penetration
• Straight-cylindrical shank compatible with standard drill chucks

Compatibility

Designed as an OEM-style jobber drill for use in any standard drill chuck accepting a 0.3580-inch straight-cylindrical shank, including drill presses, CNC machining centers, and hand-held electric drills.

Installation Notes

This bit is installed and removed by a qualified machinist or trades professional using a standard keyed or keyless drill chuck rated for the shank diameter. Secure the workpiece before drilling to prevent rotation or movement. Appropriate cutting fluid or coolant is recommended when drilling ferrous metals to extend tool life, though this bit does not support through-coolant delivery. Inspect the cutting edges for wear or chipping before each use and replace if the split point is damaged.