Chicago-latrobe 70319 Drill Bit Letter S 0.3480 in Hss Tin

Product Description

The CHICAGO-LATROBE 70319 is a jobber-length drill bit sized to letter S (0.3480 inches), designed for general-purpose drilling in cast iron and steel. Built from high speed steel with a titanium nitride (TiN) coating, this bit delivers improved surface hardness and wear resistance compared to uncoated HSS tooling. The 118-degree standard point angle and web-thinned, tapered web geometry reduce thrust at drill entry and support clean, accurate hole starts. With an overall length of 4-7/8 inches and a flute length of 3-1/2 inches, it fits standard jobber-length drill chucks. Machinists, maintenance technicians, and fabricators commonly use this bit for production and repair drilling applications.

The 70319 is suited for drilling cast iron and steel in both shop and field environments. The straight-cylindrical shank (0.3480 inches diameter) seats directly in keyed or keyless chucks across a wide range of drill presses, hand drills, and CNC drilling setups. The regular spiral flute pattern promotes consistent chip evacuation during through-hole drilling. This bit conforms to DIN 338, the international standard governing jobber-length twist drill geometry, making it a compatible replacement wherever a DIN 338 letter-S drill is specified.

Key Features

• Letter S size: 0.3480 inches diameter with a tolerance of -0.0010 to 0.0000 inches
• Titanium nitride (TiN) coating increases surface hardness and extends cutting life in ferrous materials
• 118-degree standard point angle for general-purpose drilling in cast iron and steel
• Web-thinned, tapered web reduces entry thrust and improves centering
• 2-flute regular spiral design promotes chip clearance during drilling
• Conforms to DIN 338 jobber-length twist drill standard

Compatibility

Designed as a general-purpose jobber-length drill bit conforming to DIN 338, suitable for use in any standard drill chuck accepting a 0.3480-inch straight-cylindrical shank. Primary workpiece materials are cast iron and steel.

Installation Notes

Secure the straight-cylindrical shank fully in a keyed or keyless chuck before operation and verify the bit runs true before advancing into the workpiece. Use appropriate cutting fluid or coolant for steel drilling to manage heat buildup, even though this bit does not support through-the-tool coolant delivery. Inspect the cutting edges before each use and replace the bit if chipping or excessive wear is observed. Machining and fabrication personnel should follow applicable shop safety procedures and wear appropriate eye protection when operating drilling equipment.