Osg 1591600 Spiral Point Tap 3/8-16 Unc Plug Hss

Product Description

The OSG 1591600 is a spiral point plug tap designed for cutting right-hand internal threads in a 3/8-16 UNC specification. It is manufactured from high-speed steel (HSS) with a bright finish and features three flutes with a plug chamfer for through-hole threading applications. The spiral point geometry pushes chips forward ahead of the cutting edge, reducing chip packing and improving thread quality in production environments. With a thread limit of H11 and an oversize specification of 0.005 inches, this tap is engineered for use where class 3B fit tolerance is required. Licensed machinists, maintenance technicians, and tool-and-die professionals are the primary installers.

This tap is suited for threading operations in both manual and CNC tapping applications on through-hole workpieces. Its material compatibility covers a wide range of metals including aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, high-carbon steel, and hardened steel. At 2.938 inches overall length with a 0.787-inch thread length and 0.381-inch shank diameter, it fits standard tap holders and CNC quick-change tooling. It is appropriate for job shops, maintenance and repair operations, and light manufacturing environments requiring reliable UNC thread production.

Key Features

• Spiral point geometry pushes chips forward, ideal for through-hole tapping
• Plug chamfer provides a gradual lead-in for controlled thread starting
• High-speed steel construction handles a broad range of ferrous and non-ferrous materials
• H11 thread limit with 0.005-inch oversize for Class 3B tolerance fitment
• Right-hand thread direction, compatible with standard tapping equipment
• Bright finish with no coolant-through requirement, suitable for flood or spray coolant setups

Compatibility

Designed as an OEM-style replacement or standard tooling selection for 3/8-16 UNC through-hole tapping operations across aluminum, cast iron, and carbon steel workpieces. No specific machine or holder model numbers were provided in the product data.

Installation Notes

This tap should be installed by a qualified machinist or tooling technician familiar with tap holding and CNC or manual drill press setup. Always ensure the tap is secured in a properly sized tap holder or chuck before operation, and verify spindle speed and feed rate are appropriate for the workpiece material. Use cutting fluid or coolant appropriate for the material being tapped to extend tool life. Inspect the tap for wear or chipping before each use and replace immediately if damage is detected.