Osg 2816301 Spiral Point Tap 4-40 Unc Plug Vanadium Hss

Product Description

The OSG 2816301 is a spiral point plug tap designed for cutting internal threads in a wide range of ferrous and non-ferrous materials. Built from 3% vanadium high-speed steel (HSS-E) with a steam oxide coating, it offers improved lubricity and corrosion resistance compared to uncoated tooling. The 4-40 UNC thread form, 2-flute spiral point geometry, and plug chamfer make this tap well suited for through-hole tapping where chips are pushed ahead of the cutting edge rather than packed behind it. Overall length is 1.874 inches with a 0.295-inch thread length and a 0.141-inch shank diameter. Thread limit is H4, indicating a tolerance class appropriate for general-purpose fastener applications.

This tap is used in machine shop, production, and field service environments where small-diameter 4-40 UNC threads are required. It is suited for tapping aluminum, cast iron, low-carbon steel, medium-carbon steel, high-carbon steel, alloy steel, die steel, and stainless steel. The right-hand cut and plug chamfer make it compatible with standard CNC tapping cycles, drill press setups, and hand-tapping with a T-handle or tap wrench. It is a single-piece unit, sold individually.

Key Features

• 4-40 UNC thread form with H4 thread limit for general-purpose tolerance control
• 3% vanadium HSS-E construction for enhanced wear resistance over standard M2 HSS
• Steam oxide coating improves lubricity and reduces galling, particularly in steels
• 2-flute spiral point geometry pushes chips forward, keeping flutes clear in through-hole applications
• Plug chamfer provides gradual thread engagement suitable for through-hole tapping
• Right-hand thread direction; no coolant-through feature required for this size range

Compatibility

Designed as an OEM-style cutting tool replacement for 4-40 UNC through-hole tapping operations across a broad range of workpiece materials including aluminum, stainless steel, and carbon and alloy steels.

Installation Notes

Installation of this tap should be performed by a machinist or qualified technician familiar with tapping speeds, feeds, and cutting fluid selection for the workpiece material. Secure the workpiece before beginning and ensure the tap is properly aligned to avoid tap breakage at this small diameter. Use an appropriate cutting fluid or tapping compound for the material being threaded. Follow applicable shop safety practices when operating drill presses, CNC machines, or tapping arms.