Osg 1141302 Straight Flute Tap 3/8-16 Unc Hss Plug

Product Description

The OSG 1141302 is a straight flute plug tap designed for cutting 3/8-16 UNC right-hand internal threads in a wide range of ferrous and non-ferrous materials. Manufactured from high-speed steel, this 4-flute tap carries a 2B class of fit and an H5 thread limit, making it suitable for standard tolerance threading applications in production and maintenance environments. The plug chamfer provides a balanced entry, requiring moderate starting torque while still allowing the tap to begin threading with controlled alignment. Machinists, tool-and-die professionals, and maintenance technicians use this tap in both manual and machine tapping operations.

The OSG 1141302 is well suited for through-hole and moderate blind-hole applications where straight flute geometry provides adequate chip clearance. With a 1.25-inch thread length and an overall length of 2.9375 inches, it fits standard tap holders and tapping heads used on drill presses, mills, and CNC machining centers. The straight flute design performs reliably in materials that produce short, brittle chips.

Key Features

• 3/8-16 UNC thread form with 2B class of fit for standard tolerance internal threads
• H5 thread limit for consistent fit and interchangeability with standard fasteners
• 4-flute straight flute geometry for rigidity and chip control in short-chipping materials
• Plug chamfer with moderate entry angle balances starting ease and thread engagement
• High-speed steel construction provides good wear resistance across a broad material range
• Right-hand thread direction compatible with standard tapping equipment

Compatibility

Rated for use in aluminum, cast aluminum, cast iron, high-carbon steel, low-carbon steel, and medium-carbon steel. Part of OSG Series 101.

Installation Notes

This tap is installed by machinists or maintenance technicians using standard tap holders, T-handle wrenches, or machine tapping chucks. Always apply appropriate cutting fluid for the workpiece material and ensure the tap is started perpendicular to the workpiece surface to avoid thread misalignment or tap breakage. Secure the workpiece before tapping and use a tapping block or guide when hand-tapping to maintain alignment. Do not reverse the tap under load without fully relieving cutting pressure to avoid breakage in harder materials.