Chicago-latrobe 54031 Cobalt Jobber Drill Bit No. 21

Product Description

The CHICAGO-LATROBE 54031 is a cobalt jobber-length drill bit designed for demanding metal drilling applications in industrial and trade environments. Built to Series 2550 standards, this bit carries a wire gauge size of No. 21, which equals 0.1590 inches in decimal. The 135-degree split point promotes fast, self-centering starts without a center punch, and the titanium nitride (TiN) coating extends surface hardness and wear resistance. At 3.25 inches overall length with a 2.125-inch flute, it fits standard jobber-length drill chucks. Machinists, maintenance technicians, and fabricators reach for this bit when working through hard or abrasive materials that would degrade standard high-speed steel tooling.

This bit is built specifically for cutting stainless steel and carbon steel, materials that generate high heat and work-harden quickly under poor tooling. The cobalt matrix construction handles elevated cutting temperatures better than standard HSS, making it a practical choice for structural fabrication shops, maintenance facilities, and field service work where stainless fastener holes or steel plate penetration is routine. The right-hand spiral flute evacuates chips efficiently, reducing recutting and heat buildup during the cut.

Key Features

• Cobalt construction for superior heat resistance when drilling stainless steel and hardened alloys
• 135-degree split point for self-centering starts and reduced thrust requirement
• Titanium nitride (TiN) coating increases surface hardness and extends tool life
• Two-flute right-hand spiral design promotes efficient chip evacuation
• Straight-cylindrical shank at 0.1590 inches diameter fits standard drill chucks
• Meets DIN 338 and NAS 907 Type J standards for dimensional and performance consistency

Compatibility

Designed for use in standard jobber-length drill chucks accepting a 0.1590-inch straight-cylindrical shank. Primary workpiece materials are stainless steel and carbon steel, consistent with Series 2550 heavy-duty cobalt tooling applications.

Installation Notes

Secure the shank fully in a keyed or keyless chuck before operation and confirm the bit runs true before contact with the workpiece. Use cutting fluid or coolant when drilling stainless steel to manage heat buildup and prevent work hardening at the cutting edge. Allow the split point to establish the hole location before applying full feed pressure. Inspect the cutting edges for wear between uses, as a dull cobalt bit on stainless steel accelerates work hardening and shortens tool life.