Osg 1712401 Spiral Point Sti Tap 2-56 Unc Plug Hss

Product Description

The OSG 1712401 is a spiral point STI tap designed for tapping screw thread insert (STI) holes to the 2-56 UNC thread standard. It is ground from vanadium high-speed steel and carries an oxide finish for basic lubricity and corrosion resistance during storage. The plug chamfer configuration provides gradual thread engagement, making it well-suited for through-hole tapping applications. With 2 flutes and an H2 thread limit, this tap produces consistent, controlled threads in a variety of workpiece materials. Overall length is 1.882 inches, and thread length is 0.259 inches. Licensed machinists, tool-and-die makers, and precision metalworkers are the primary users of this tap.

This tap is used in applications where a screw thread insert is being installed into a tapped hole, most commonly in aerospace, industrial maintenance, and precision machining environments. The 2-56 UNC thread size targets fine, small-diameter fastening situations where STI inserts are required to restore or reinforce thread integrity. The plug chamfer makes it appropriate for through-hole work where chip ejection ahead of the tap is an advantage. Series 301 designates this as part of OSG's standard STI tap line.

Key Features

• 2-56 UNC thread form sized for STI insert installation
• Vanadium high-speed steel construction for wear resistance in production tapping
• Oxide finish provides basic surface protection and run-in lubricity
• Plug chamfer enables smooth entry and is optimized for through-hole tapping
• H2 thread limit ensures tight, consistent thread tolerance control
• Compact 1.882-inch overall length suited for small workpieces and restricted-access setups

Compatibility

Designed for use in STI tapping applications requiring a 2-56 UNC thread form; intended for use with corresponding 2-56 STI insert systems in through-hole configurations.

Installation Notes

This tap is installed by machinists using a tap wrench, tapping head, or CNC rigid-tapping setup. Secure the workpiece fully before tapping and apply appropriate cutting fluid for the workpiece material to extend tap life and improve thread quality. Do not force the tap if resistance increases unexpectedly, as breakage in small-diameter taps is difficult to recover from. Follow applicable shop safety procedures and manufacturer recommendations for cutting speeds.