Osg 2940408 Spiral Flute Tap 1/4-28 Unf Ticn Vanadium Hss

Product Description

The OSG 2940408 is a spiral flute tap designed for threading 1/4-28 UNF internal threads in a wide range of ferrous materials. Built from vanadium high-speed steel and finished with a titanium carbonitride (TiCN) coating, this tap delivers increased wear resistance and extended tool life compared to standard uncoated HSS taps. The modified bottoming chamfer allows the tap to cut threads close to the bottom of a blind hole. With a 45-degree helix angle, the right-hand spiral flutes pull chips up and out of the hole during the threading operation, reducing the risk of chip packing and tap breakage. Series 290 from OSG, sold individually.

The 2940408 is suited for production and maintenance threading applications in alloy steel, carbon steel, cast iron, stainless steel, die steel, and hardened steel. It is commonly used in machine shops, tool rooms, and MRO operations where fine-thread 1/4-28 UNF fastener holes are required. The modified bottoming chamfer makes it particularly useful when threads must be cut into shallow or blind-hole conditions where a standard plug or taper chamfer cannot reach full thread depth.

Key Features

• Vanadium high-speed steel construction for toughness and wear resistance in hard and abrasive materials
• TiCN coating increases surface hardness and reduces friction, extending tool life in production environments
• 45-degree right-hand spiral flutes evacuate chips upward, ideal for blind-hole threading
• Modified bottoming chamfer cuts threads closer to the bottom of a blind hole than plug-chamfer taps
• H5 thread limit for controlled oversize tolerance, suitable for use with standard UNF thread gauges
• Right-hand thread direction compatible with standard CNC and manual tapping equipment

Compatibility

Designed for cutting 1/4-28 UNF right-hand internal threads. Suitable for use in alloy steel, carbon steel, cast iron, stainless steel, die steel, and hardened steel workpieces as specified by OSG for this series.

Installation Notes

This tap should be installed by a machinist or tooling technician familiar with tapping speeds and feeds for the workpiece material. Ensure the spindle or tap handle is properly aligned with the hole axis before engagement to prevent tap breakage. Use an appropriate cutting fluid or tapping compound for the material being threaded. Inspect the tap for wear or chipping before each use, particularly when threading hardened or abrasive materials.