Chicago-latrobe 70155 Drill Bit Size 55 Hss Tin Coated

Product Description

The CHICAGO-LATROBE 70155 is a wire gauge size 55 jobber length drill bit ground from high speed steel and finished with a titanium nitride (TiN) coating. It cuts a 0.0520-inch diameter hole and measures 1-7/8 inches overall length with a 7/8-inch flute length. The standard 118-degree split point, combined with a web-thinned, tapered web configuration, reduces the force required to start a hole and minimizes walking on entry. The straight-cylindrical shank seats in standard drill chucks without modification. This is a general-purpose bit intended for use by machinists, maintenance technicians, and metalworking tradespeople who need consistent, repeatable small-diameter holes.

The 70155 is suited for drilling cast iron and steel in both production and maintenance environments. The two-flute spiral configuration with a regular spiral type provides efficient chip evacuation in short-to-medium depth holes typical of jobber length work. No coolant-through capability is present, so conventional flood coolant or cutting oil applied externally is the standard practice for steel workpieces. The Series 150T designation indicates compliance with DIN 338 standards for jobber length drill geometry.

Key Features

• Wire gauge size 55 with 0.0520-inch decimal diameter and diameter tolerance of -0.0005 to 0.0000 inches
• Titanium nitride (TiN) coating increases surface hardness and extends tool life in steel and cast iron
• 118-degree standard point angle with web-thinned, tapered web for reduced thrust and clean entry
• Right-hand cut, two-flute regular spiral for efficient chip clearance in jobber length drilling
• Straight-cylindrical shank (0.0520-inch diameter) fits standard drill chucks and collets
• Meets DIN 338 jobber length geometry standard

Compatibility

Designed as a general-purpose jobber length drill bit for use in standard drill chucks and collets that accept a 0.0520-inch straight-cylindrical shank. Primary workpiece materials are cast iron and steel.

Installation Notes

A licensed machinist or qualified maintenance technician should secure the workpiece firmly before drilling to prevent movement at small diameters. Ensure the drill chuck is properly tightened and the shank is fully seated before operation. Apply cutting oil or external flood coolant when drilling steel to manage heat buildup and extend bit life. Inspect the cutting edges for wear or chipping before each use, as small-diameter bits are susceptible to breakage if run in worn condition.