Osg 1708108 Spiral Point Tap 3/8-24 Unf Ticn Coated

Product Description

The OSG 1708108 is a spiral point tap designed for threading 3/8-24 UNF internal threads in challenging materials. Built from powdered metal with a TiCN coating, this tap handles hardened steel, stainless steel, high-nickel alloys, and titanium where standard high-speed steel taps wear prematurely. The 3-flute spiral point design pushes chips forward ahead of the cutting zone, keeping flutes clear in through-hole applications. It is sized for a 3B class of fit with an H3 thread limit, providing the controlled tolerance required for precision fastener assemblies. Machinists, toolroom technicians, and maintenance mechanics working in aerospace, industrial, and high-alloy fabrication environments are the primary users of this tap.

The 1708108 is suited for through-hole tapping operations in production and job-shop environments where material hardness and work-hardening tendencies demand a robust tool. Its plug chamfer allows easy starting in a pre-drilled hole. Applications include threading fastener holes in stainless steel structural components, high-nickel alloy valve bodies, and titanium aerospace brackets. The right-hand thread direction is standard for UNF fastener systems. The Series 312NI designation identifies it within the OSG 312NI line, which is engineered specifically for nickel-based and hard-to-machine alloys.

Key Features

• TiCN coating reduces friction and extends tool life in hard and abrasive materials
• Powdered metal substrate provides superior wear resistance over conventional HSS
• Spiral point geometry pushes chips forward, preventing chip packing in through-hole tapping
• H3 thread limit and 3B class of fit for controlled, precision thread production
• Plug chamfer for reliable engagement in pre-drilled through holes
• 3-flute design balances chip evacuation with cutting edge strength

Compatibility

Designed for tapping 3/8-24 UNF through holes in hardened steel, stainless steel, high-nickel alloys, and titanium. Suitable for use with standard 3/8-inch tap holders and CNC tapping attachments configured for right-hand, UNF threading cycles.

Installation Notes

Install in a rigid tapping holder or synchronous CNC tapping attachment to maintain thread accuracy and prevent tap breakage. Ensure the pilot hole is drilled to the correct diameter for 3/8-24 UNF before tapping. Apply appropriate cutting fluid for the workpiece material — sulfurized or chlorinated cutting oil is commonly used for stainless and high-nickel alloys. Inspect the tap for wear or chipping between uses; do not continue tapping with a damaged cutting edge.