Osg 1645004402 Spiral Flute Tap 4-40 Unc Tin Vanadium Hss

Product Description

The OSG 1645004402 is a spiral flute tap designed for cutting 4-40 UNC internal threads in a wide range of metals. Built from vanadium high-speed steel and coated with titanium nitride (TiN), this tap delivers extended tool life and reduced friction in demanding tapping operations. It features a modified bottoming chamfer, a 45-degree helix angle, and a 2B class of fit, making it suited for precision thread production where near-blind or shallow-depth holes are common. Licensed machinists and toolroom technicians are the primary users of this tool.

This tap is engineered for use in alloy steel, cast iron, high-carbon steel, low-carbon steel, medium-carbon steel, and stainless steel. The modified bottoming chamfer allows threading to be driven close to the bottom of a blind hole without a full bottoming tap setup. With a tapping depth of 0.5625 inches and an overall length of 2.25 inches, this tap fits standard tap wrenches and CNC tapping heads used in both shop and production environments. It is part of OSG Series 16450.

Key Features

• 4-40 UNC thread form, right-hand thread direction, 40 threads per inch
• TiN coating reduces friction and extends tool life compared to uncoated HSS
• Vanadium high-speed steel construction handles hard and abrasive workpiece materials
• 45-degree right-hand spiral flute evacuates chips upward, ideal for blind-hole applications
• Modified bottoming chamfer allows threading close to the base of a blind hole
• H2 thread limit and 2B class of fit for accurate, consistent thread tolerance

Compatibility

Designed as an OEM-style production tap for use in machines and tap wrenches configured for 4-40 UNC threading in alloy steel, cast iron, high-carbon steel, low-carbon steel, medium-carbon steel, and stainless steel workpieces.

Installation Notes

This tap should be installed and operated by a qualified machinist or toolroom technician. Always secure the workpiece and ensure the tap is properly aligned to the pilot hole before beginning the threading operation. Use an appropriate cutting fluid or tapping compound rated for the workpiece material to protect the coating and maximize thread quality. Never force a tap in a blind hole without confirming chip clearance, as packing can cause tap breakage.