Osg 1650502508 Spiral Flute Tap 3/8-16 Unc Ticn Coated

Product Description

The OSG 1650502508 is a spiral flute tap designed for threading 3/8-16 UNC holes in a wide range of metallic workpiece materials. Built from powdered metal (grade PMT15) with a TICN coating and a 45-degree helix angle, this tap evacuates chips upward out of the hole, making it well suited for blind-hole tapping applications. The modified bottoming chamfer allows threading close to the bottom of a blind hole while still providing enough lead-in for controlled entry. It produces a Class 3B fit with an H3 thread limit, meeting the precision requirements typical in structural and mechanical fastening applications. Licensed machinists, tool-and-die makers, and maintenance technicians working in a shop or field environment are the primary users.

This tap is rated for use in alloy steel, aluminum, cast aluminum, cast iron, hardened steel, high-carbon steel, low-carbon steel, medium-carbon steel, and stainless steel. The 45-degree spiral flute geometry is particularly effective in interrupted cuts and gummy materials such as aluminum and stainless steel where straight-flute taps tend to pack chips. It is sized for standard 3/8-16 UNC through or blind holes and fits the OSG Series 16505 product family. Thread length is 0.5 inches (12.7 mm) and overall length is 100 mm. Right-hand thread direction matches standard fastener convention.

Key Features

• 45-degree helix angle spiral flute design evacuates chips upward, ideal for blind-hole tapping
• Modified bottoming chamfer enables threading near the bottom of a blind hole
• TICN coating improves wear resistance and reduces friction across a broad range of workpiece materials
• Powdered metal construction (grade PMT15) provides consistent hardness and toughness compared to standard HSS
• H3 thread limit and Class 3B fit deliver precision threading for structural and mechanical fastener applications
• Rated for nine workpiece materials including stainless steel, cast iron, and hardened steel

Compatibility

Designed for use in 3/8-16 UNC threaded hole applications across alloy steel, aluminum, cast aluminum, cast iron, hardened steel, high-carbon steel, low-carbon steel, medium-carbon steel, and stainless steel workpieces. Part of the OSG Series 16505 spiral flute tap family.

Installation Notes

This tap is installed by machinists or maintenance technicians using a tapping machine, drill press, or CNC machining center with a properly sized tap holder. Always ensure the pilot hole diameter matches the recommended tap drill size for 3/8-16 UNC before tapping. Use an appropriate cutting fluid matched to the workpiece material — sulfurized oil for steel, lubricant-based fluid for aluminum — to extend tool life and improve thread quality. Inspect the tap for chipping or wear before each use, particularly when working in hardened steel.