Osg 1707101 Spiral Point Tap 1/4-20 Unc 3 Flute Plug

Product Description

The OSG 1707101 is a spiral point plug tap designed for threading through-holes in demanding materials. Built from powdered metal with a steam oxide coating, it cuts 1/4-20 UNC threads to a 3B class of fit with an H3 thread limit. The spiral point geometry pushes chips forward ahead of the cut, keeping the flutes clear in through-hole applications. With 3 flutes and a plug chamfer, this tap is suited for general threading where entry alignment and chip evacuation are priorities. It is sized for use in hand tap handles or machine tapping operations by machinists, toolmakers, and maintenance technicians.

This tap is rated for use in hardened steel, stainless steel, high-nickel alloys, and titanium — materials that demand a tough substrate and a coating that reduces galling. The 1/4-20 UNC thread form is one of the most common fastener sizes in industrial and mechanical assembly, making this tap a regular tool in production and repair shops. Right-hand thread direction and a standard shank diameter make it compatible with conventional tap holders and CNC tapping heads. The Series 312NI designation identifies it within the OSG high-performance tap line targeting difficult-to-machine alloys.

Key Features

• Spiral point geometry pushes chips forward, ideal for through-hole tapping
• Powdered metal construction for improved toughness in difficult alloys
• Steam oxide coating reduces friction and provides corrosion resistance during storage and use
• H3 thread limit and 3B class of fit for consistent, production-tolerance threads
• Rated for hardened steel, stainless steel, high-nickel alloy, and titanium
• Right-hand cut, plug chamfer, 3 flutes — standard configuration for manual and machine tapping

Compatibility

Designed for through-hole tapping of 1/4-20 UNC threads in hardened steel, stainless steel, high-nickel alloy, and titanium workpieces. Fits standard 1/4-inch tap holders and CNC tapping chucks accepting a 0.255-inch shank diameter. Not designed for coolant-through tooling setups.

Installation Notes

A licensed machinist or skilled maintenance technician should select appropriate cutting fluid for the workpiece material before tapping, particularly when working stainless or high-nickel alloys. Ensure the workpiece is securely fixtured and the tap is aligned perpendicular to the hole before engagement. For machine tapping, verify spindle speed and feed rate match the tap manufacturer recommendations for the specific material. Do not back-tap or use this tool in blind holes where chip packing cannot be cleared.