Osg 1700301 Spiral Point Tap 1/4-28 Unf Plug H4 2B

Product Description

The OSG 1700301 is a spiral point tap designed for threading 1/4-28 UNF internal threads in demanding materials. The spiral point geometry pushes chips forward ahead of the cutting zone, making it well suited for through-hole tapping operations. Built from powdered metal with a steam oxide finish, this tap delivers improved wear resistance and lubricity compared to standard HSS tools. It features a plug chamfer, 3 flutes, an H4 thread limit, and a 2B class of fit. Overall length is 2.5 inches with a thread length of 0.62 inches and a shank diameter of 0.255 inches. Machinists, tool and die makers, and maintenance technicians use this tap in production and repair settings.

The OSG 1700301 is suited for tapping through holes in hardened steel, stainless steel, high-nickel alloy, titanium, alloy steel, and die steel. Its powdered metal construction handles the elevated hardness and work-hardening tendencies of these materials better than conventional HSS. Right-hand thread direction matches standard UNF fastener orientation. The 1/4-28 UNF thread form is common in aerospace, automotive, and precision mechanical assemblies where a finer thread pitch is required over standard UNC. This tap is appropriate for both manual tapping and CNC machine tapping without coolant-through requirements.

Key Features

• Spiral point geometry pushes chips forward — optimized for through-hole applications
• Powdered metal construction provides increased hardness and toughness over standard HSS
• Steam oxide coating improves lubricity and reduces built-up edge on difficult materials
• H4 thread limit with 2B class of fit for consistent, inspectable thread tolerance
• Plug chamfer (3-5 thread lead) allows gradual thread engagement and reduced torque requirements
• No coolant-through required — compatible with flood, mist, or paste lubricant setups

Compatibility

Designed for through-hole tapping of 1/4-28 UNF threads in hardened steel, stainless steel, high-nickel alloy, titanium, alloy steel, and die steel. Part of OSG Series 312.

Installation Notes

Use this tap with a properly sized 1/4-28 UNF tap drill to achieve the correct minor diameter before threading. Secure the workpiece firmly and apply appropriate cutting fluid or tapping paste for the material being threaded. For CNC applications, verify spindle speed and feed rate against the material specification before running. Inspect the tap for wear or chipping after each use in hardened or exotic materials, as these impose elevated cutting loads.