Osg 1645014203 Spiral Flute Tap 1/4-20 Unc Tin Vanadium Hss

Product Description

The OSG 1645014203 is a spiral flute tap designed for cutting internal threads in a wide range of ferrous materials. It produces a 1/4-20 UNC right-hand thread to a 3B class of fit using a modified bottoming chamfer, making it suited for threading holes where full thread depth close to the bottom is required. The tap is manufactured from vanadium high-speed steel and carries a titanium nitride (TiN) coating that increases surface hardness and reduces friction, extending tool life in production environments. Overall length is 3.15 inches. This tool is intended for use by machinists, toolroom technicians, and maintenance professionals working with manual or CNC tapping equipment.

This tap is appropriate for threading operations in alloy steel, cast iron, high-carbon steel, low-carbon steel, medium-carbon steel, and stainless steel. The 45-degree helix angle and two-flute spiral configuration help pull chips up and out of the hole during tapping, which is particularly useful in blind-hole applications. The modified bottoming chamfer allows threading closer to the bottom of a blind hole than a standard plug tap. Typical applications include precision machined components, structural assemblies, and repair work where a clean, close-tolerance 1/4-20 thread is required in ferrous stock.

Key Features

• 1/4-20 UNC thread form, 3B class of fit for standard tolerance internal threads
• Modified bottoming chamfer for threading near the bottom of blind holes
• 45-degree right-hand spiral flute geometry promotes upward chip evacuation
• TiN coating improves wear resistance and reduces built-up edge on the cutting faces
• Vanadium high-speed steel construction for toughness in ferrous material applications
• H3 thread limit for consistent fit across production runs

Compatibility

Designed for tapping 1/4-20 UNC threads in alloy steel, cast iron, high-carbon steel, low-carbon steel, medium-carbon steel, and stainless steel. Part of OSG Series 16450.

Installation Notes

Install in a tap wrench, tapping head, or CNC rigid-tapping spindle with the correct 0.191-inch square drive. Ensure the workpiece is securely fixtured and the tap is aligned perpendicular to the hole before applying cutting pressure. Apply appropriate cutting fluid for the material being tapped to prevent galling, particularly in stainless steel. Inspect the tap for wear or chipping before each use and do not force a dull tap, as breakage in blind holes is difficult to recover from.