Osg 1732708 Spiral Flute Tap 1/4-28 Unf Modified Bottoming

Product Description

The OSG 1732708 is a spiral flute tap designed for cutting internal right-hand threads to the 1/4-28 UNF standard. Built from vanadium high-speed steel with a TICN coating, this tap delivers extended tool life in demanding applications. The modified bottoming chamfer allows threading closer to the bottom of blind holes compared to standard taper or plug chamfers. With a 45-degree helix angle and three flutes, it efficiently evacuates chips upward during cutting, making it well-suited for interrupted cuts and through-hole or shallow blind-hole work. The H3 thread limit and 3B class of fit ensure precise, consistent thread geometry on every pass.

This tap is intended for use in stainless steel, high-carbon steel, low-carbon steel, and medium-carbon steel workpieces. The TICN coating reduces friction and heat buildup, which is especially beneficial when threading stainless steel. It is part of OSG EXOTAP VA3 Series 303, a line engineered for high-performance tapping in production and maintenance machining environments. Machinists and tool-and-die tradespeople use this tap in CNC machining centers, drill presses, and manual tapping applications where a 1/4-28 UNF thread is required.

Key Features

• 45-degree right-hand spiral flute design evacuates chips upward for cleaner blind-hole threading
• Modified bottoming chamfer allows threading to within a few threads of the hole bottom
• TICN coating reduces friction and heat, extending tool life in ferrous materials
• Vanadium high-speed steel construction provides toughness and wear resistance
• H3 thread limit with 3B class of fit ensures consistent, accurate thread production
• No coolant-through requirement simplifies setup in standard tapping operations

Compatibility

Designed for cutting 1/4-28 UNF right-hand internal threads in stainless steel, high-carbon steel, low-carbon steel, and medium-carbon steel. Part of the OSG EXOTAP VA3 Series 303.

Installation Notes

This tap should be installed in a tap holder or floating collet sized for the 0.381-inch shank diameter. Power down or de-energize any CNC or power tapping equipment before changing tooling. Use appropriate cutting fluid for the workpiece material, particularly when threading stainless steel, to reduce work hardening and galling. Dispose of metal chips per standard shop safety practices and inspect thread form periodically with a 3B go/no-go gauge.