Osg 1725401 Spiral Point Tap 1-8 Unc 3 Flute Hss

Product Description

The OSG 1725401 is a spiral point plug tap designed for threading operations in a wide range of ferrous materials. Built from vanadium high-speed steel (HSS-E) with a steam oxide coating, it handles hardened steel, low-carbon steel, medium-carbon steel, and stainless steel applications. The spiral point geometry pushes chips forward ahead of the cutting zone, reducing chip packing in through-hole applications. The plug chamfer distributes the cutting load across several leading threads, making it well-suited for production threading where consistent thread quality and tap life matter. At 5.126 inches overall length with a 1.562-inch thread length, this tap is sized for standard machine spindles and tapping arms used in shop and field environments.

This tap is intended for through-hole tapping at 1-8 UNC thread size with a 3B class of fit, meaning it produces threads conforming to standard external fastener engagement tolerances. It is appropriate for use on machining centers, drill presses with tapping attachments, and dedicated tapping machines in residential and commercial fabrication, maintenance, and repair operations. The right-hand thread direction and H4 thread limit make it compatible with standard UNC toolholders and CNC tapping cycles. Machinists, millwrights, and maintenance technicians working in metal fabrication, HVAC equipment repair, and general mechanical assembly will find this tap applicable for a broad range of through-hole threading tasks.

Key Features

• Spiral point geometry pushes chips forward, preventing chip packing in through-hole applications
• Vanadium high-speed steel (HSS-E) construction for increased wear resistance and toughness
• Steam oxide coating reduces friction and improves lubricity during cutting
• Plug chamfer distributes cutting load across multiple leading threads for smoother entry
• H4 thread limit and 3B class of fit for standard UNC thread tolerance compliance
• Right-hand thread direction compatible with standard machine tapping setups

Compatibility

Designed for through-hole tapping in hardened steel, low-carbon steel, medium-carbon steel, and stainless steel. Compatible with standard 1-8 UNC toolholders, tapping chucks, and CNC tapping cycles. No coolant-through capability; external cutting fluid application is required.

Installation Notes

Installation should be performed by a qualified machinist or maintenance technician familiar with tapping operations. Ensure the workpiece is securely fixtured and the tap is properly aligned with the pilot hole before beginning the threading cycle to prevent tap breakage. Apply appropriate cutting fluid for the material being tapped; do not run dry. Power down or disengage the tapping machine before changing taps or clearing chips from the work area.