Osg 1772001 Spiral Point Tap 4-40 Unc Plug

Product Description

The OSG 1772001 is a spiral point tap designed for cutting 4-40 UNC internal threads in challenging materials. Built from powdered metal and finished with a steam oxide coating, this plug-chamfer tap pushes chips forward during the cut, keeping flute channels clear and reducing the risk of chip packing in blind or through holes. With an H4 thread limit and a 9/16-inch thread length, the 1772001 is well suited for precision threading applications where tight tolerances and consistent thread form are required. It weighs 0.005 pounds and measures 1.874 inches overall length.

This tap is intended for use in hardened steel, stainless steel, high-nickel alloys, and titanium — materials that demand a robust powdered metal construction and a friction-reducing oxide surface treatment. The plug chamfer provides a gradual lead-in, making it appropriate for through-hole threading or holes with sufficient relief at the bottom. Licensed machinists, toolroom technicians, and precision sheet metal workers are the typical users. The 4-40 UNC thread size is common in small-fastener applications including instrument panels, enclosures, and light mechanical assemblies.

Key Features

• Spiral point design pushes chips forward, preventing packing in through-hole applications
• Powdered metal construction provides increased wear resistance in tough alloys
• Steam oxide coating reduces friction and helps with chip flow
• Plug chamfer (3-5 thread lead) for general-purpose through-hole and open-bottom threading
• H4 thread limit for controlled oversize fit, suitable for use with coatings or in tighter tolerance assemblies
• Right-hand thread direction, 2 flutes, no coolant-through requirement

Compatibility

Designed for threading 4-40 UNC right-hand internal threads in hardened steel, stainless steel, high-nickel alloy, and titanium workpieces per the OSG Series 312NI product family specifications.

Installation Notes

Installation should be performed by a qualified machinist or toolroom technician using a properly aligned tapping head, tap wrench, or CNC tapping cycle. Ensure the workpiece is securely fixtured and the tap is started perpendicular to the drilled hole to prevent cross-threading or tap breakage. Apply an appropriate cutting fluid for the workpiece material before and during tapping. Inspect the tap for wear or chipping before each use, as small-diameter taps in hard materials are susceptible to breakage under side load or misalignment.