Chicago-latrobe 50746 Extra Length Drill Bit 0.4062 in Hss

Product Description

The CHICAGO-LATROBE 50746 is an extra length, high speed steel twist drill bit designed for long-reach drilling applications in metal fabrication, maintenance, and industrial environments. Built to Series 120X specifications, it features a 0.4062-inch diameter, a 118-degree notched drill point, and a web-thinned, tapered web construction that reduces thrust and improves chip clearing. The 10-inch overall length and 7.5-inch flute length give it the reach needed to bore through deep sections, thick stacked materials, or hard-to-access locations where standard-length bits cannot perform. The oxide finish provides mild lubricity and corrosion resistance. Machinists, toolroom technicians, and maintenance mechanics are the primary users.

This bit is suited for drilling cast iron and steel in applications that require extended reach beyond what a jobber-length bit provides. Typical scenarios include deep-hole work in structural components, through-hole drilling in heavy plate, and production drilling where a straight-cylindrical shank must seat in a standard drill chuck or collet. The right-hand spiral flute and regular spiral type make it compatible with conventional vertical mills, drill presses, and hand-held power drills. The 0.4062-inch shank diameter matches the cutting diameter, allowing direct chucking without adapters.

Key Features

• High speed steel construction for durability in steel and cast iron applications
• 118-degree notched point with web thinning reduces entry thrust and improves centering
• 10-inch overall length and 7.5-inch flute length for deep or long-reach drilling
• Straight-cylindrical shank at 0.4062 inches for direct chuck mounting
• Oxide finish provides mild corrosion resistance and lubricity
• Right-hand cutting, 2-flute spiral design for standard chip evacuation
• Diameter tolerance held to +0.0000 to -0.0010 inches for close-tolerance work

Compatibility

Designed for use in standard drill chucks and collets accepting a 0.4062-inch straight-cylindrical shank. Primary workpiece materials are cast iron and steel. Series 120X general-purpose extra length designation.

Installation Notes

A licensed machinist or qualified maintenance technician should select the appropriate spindle speed based on workpiece material and cutting diameter before drilling. Ensure the workpiece is securely fixtured and the chuck or collet is fully tightened before operation. Apply cutting fluid when drilling steel to extend tool life and manage heat buildup. Inspect the cutting edges for wear or chipping before each use and replace the bit if the point is damaged to maintain dimensional accuracy.