Osg 1651501908 Spiral Point Tap 1/4-28 Unf Ticn

Product Description

The OSG 1651501908 is a high-performance spiral point tap designed for threading 1/4-28 UNF holes in a wide range of ferrous and non-ferrous metals. Manufactured from powdered metal (grade PMT15) and finished with a TiCN coating, this tap delivers extended tool life in demanding production environments. The plug chamfer provides gradual thread engagement, making it well suited for through-hole tapping operations. With a 3-flute spiral point geometry, it pushes chips forward ahead of the cut, reducing chip packing and lowering torque requirements. Overall length is 3.15 inches, and thread length is 0.59 inches. Thread direction is right hand, thread limit H3, and class of fit is 3B. Machinists, toolroom technicians, and CNC operators are the primary users of this tap.

This tap is intended for through-hole tapping in materials including alloy steel, aluminum, cast aluminum, cast iron, hardened steel, high-carbon steel, low-carbon steel, medium-carbon steel, stainless steel, and die steel. The 1/4-28 UNF thread form is common in aerospace, automotive, and precision mechanical assemblies where fine thread engagement and strong holding force are required. The H3 thread limit is appropriate for standard 3B tolerance class fits. This tap is not designed for blind-hole applications where chip evacuation is limited.

Key Features

• 1/4-28 UNF thread form with H3 thread limit for 3B class of fit
• Powdered metal construction (PMT15 grade) for wear resistance and toughness
• TiCN coating reduces friction and extends tool life across a broad material range
• 3-flute spiral point geometry pushes chips forward in through-hole applications
• Plug chamfer for gradual thread engagement and reduced tap breakage risk
• Right-hand thread direction; no coolant-through feature

Compatibility

Designed for through-hole tapping of 1/4-28 UNF threads in alloy steel, aluminum, cast aluminum, cast iron, hardened steel, high-carbon steel, low-carbon steel, medium-carbon steel, stainless steel, and die steel. Part of OSG Series 16515 high-performance spiral point taps.

Installation Notes

This tap is installed and operated by machinists or CNC technicians using a tapping head, tap wrench, or machine spindle set to the correct RPM and feed rate for the workpiece material. Ensure the tap is properly aligned with the drilled pilot hole before engagement to prevent tap breakage. Apply appropriate cutting fluid for the workpiece material to improve surface finish and extend tap life. Do not use this tap in blind holes where forward chip ejection is not possible.