Hertel 04139192 Cobalt Jobber Drill Bit No 72 Wire Size

Product Description

The HERTEL 04139192 is a cobalt jobber-length drill bit in wire gauge size No. 72, with a decimal diameter of 0.0250 inches. It features a 135-degree split point with web thinning for fast, accurate starts without a center punch. The oxide and TiN coating improves surface hardness and heat resistance, making this bit suited for drilling harder metals, stainless steel, and alloys. Overall length is 1.125 inches with a flute length of 0.3125 inches and a straight-cylindrical shank. This is a heavy-duty grade bit used in precision machining, tool and die, and HVAC or plumbing fabrication shops where small-diameter holemaking is required.

This bit is designed for holemaking in metalworking applications where a small-diameter, high-performance drill is needed. Typical use cases include drilling pilot holes, instrument panels, sheet metal, and component parts in light manufacturing or field fabrication. The right-hand spiral flute and regular spiral type support efficient chip evacuation in through-hole drilling. This size is common in trade shops, HVAC equipment fabrication, and electrical panel work where No. 72 wire gauge holes are specified.

Key Features

• Cobalt construction with oxide and TiN coating for heat and wear resistance in hard-material drilling
• 135-degree split point with web thinning reduces walking and cutting force at entry
• Wire gauge No. 72 diameter at 0.0250 inches for precision small-bore holemaking
• Right-hand cutting direction with regular spiral flute for clean chip removal
• Straight-cylindrical shank fits standard drill chucks without adapters
• Heavy-duty grade construction for extended tool life under repeated use

Compatibility

Designed as a jobber-series replacement or stock drill bit for any standard drill chuck accepting a 0.0250-inch straight-cylindrical shank, compatible with benchtop drill presses, CNC drilling centers, and hand drills used in precision metalworking applications.

Installation Notes

Installation and use of this drill bit should be performed by qualified machinists or trade professionals familiar with small-diameter drilling techniques. Secure the shank fully in the chuck and verify runout before use, as small-diameter cobalt bits are brittle under lateral load. Use appropriate cutting fluid or coolant for hard metals to extend bit life and prevent heat buildup. Operate at manufacturer-recommended RPM for the material being drilled — excessive feed rate is the primary cause of bit breakage at this diameter.