Osg 1645014284 Spiral Flute Tap 1/4-28 Unf Tin Vanadium Hss

Product Description

The OSG 1645014284 is a spiral flute tap designed for cutting 1/4-28 UNF internal threads in a wide range of steel and stainless steel workpieces. Ground from vanadium high-speed steel (HSS) and finished with a titanium nitride (TiN) coating, it delivers extended tool life and reduced friction during the tapping operation. The modified bottoming chamfer allows threading close to the bottom of blind holes. With a 45-degree helix angle and 2 right-hand flutes, this tap efficiently evacuates chips upward out of the hole, making it well suited for blind-hole applications in production and maintenance machining environments. It is used by machinists, tool-and-die makers, and maintenance technicians.

This tap is intended for tapping 1/4-28 UNF threads in alloy steel, low-carbon steel, medium-carbon steel, high-carbon steel, cast iron, and stainless steel. The 2B class of fit produces standard commercial-tolerance threads appropriate for most fastener and mechanical assembly applications. With a tapping depth of 1.000 inch and an overall length of 3.150 inches (80 mm), it fits standard tap handles and CNC tapping chucks used in both manual and machine tapping setups.

Key Features

• 1/4-28 UNF right-hand thread form, 2B class of fit, H4 thread limit
• Vanadium high-speed steel construction for toughness and wear resistance in ferrous materials
• TiN coating reduces friction and extends tool life compared to uncoated HSS taps
• 45-degree right-hand spiral flutes pull chips up and out of blind holes
• Modified bottoming chamfer allows threading near the bottom of blind-hole applications
• Part of OSG Series 16450 for consistent geometry and replacement sourcing

Compatibility

Designed for use in alloy steel, cast iron, high-carbon steel, low-carbon steel, medium-carbon steel, and stainless steel workpieces (primary material codes P and M). Compatible with standard 1/4-inch tap holders, T-handle wrenches, and CNC tapping chucks that accept a 0.255-inch shank diameter.

Installation Notes

This tap is installed by qualified machinists or maintenance technicians using a tap wrench, tapping fixture, or CNC machine with a synchronized tapping cycle. Ensure the workpiece is securely clamped and the pilot hole is drilled to the correct tap-drill diameter for 1/4-28 UNF threads before starting. Apply appropriate cutting fluid for the workpiece material to prevent galling, particularly when tapping stainless steel. Do not force the tap if resistance increases suddenly; back off to clear chips and inspect for breakage.