Osg 1740805 Spiral Point Tap 5/16-18 Unc Tin Hss

Product Description

The OSG 1740805 is a spiral point plug tap designed for threading 5/16-18 UNC holes in a wide range of metallic workpiece materials. It features three flutes with a plug chamfer and is manufactured from Vanadium High Speed Steel (HSS-E) with a Titanium Nitride (TiN) coating for extended tool life and reduced friction. The H3 thread limit and 3B class of fit make it suitable for standard fastener applications requiring close tolerances. Right-hand cut, no coolant-through design. Overall length is 2.72 inches with a thread length of 0.665 inches (1-1/8 inches nominal) and a shank diameter of 0.318 inches.

This tap is used in machine shop, maintenance, and production threading operations across industries including HVAC fabrication, plumbing, electrical enclosure work, and general mechanical assembly. It is suited for threading through-holes in aluminum, cast iron, low-, medium-, and high-carbon steel, alloy steel, die steel, stainless steel, and hardened steel. Spiral point geometry pushes chips forward ahead of the tap, making it most effective in through-hole applications rather than blind holes.

Key Features

• 5/16-18 UNC thread form, H3 thread limit, 3B class of fit for standard tolerance applications
• Vanadium High Speed Steel (HSS-E) construction for toughness in demanding materials
• TiN coating reduces friction and improves wear resistance for longer tool life
• Plug chamfer with spiral point geometry pushes chips forward — optimized for through-hole threading
• Right-hand cut, three flutes, no coolant-through requirement
• Compatible with a broad material range including stainless steel, alloy steel, cast iron, and aluminum

Compatibility

Designed for through-hole threading in aluminum, hardened steel, stainless steel, high-carbon steel, low-carbon steel, medium-carbon steel, alloy steel, die steel, and cast iron. OSG Series 320.

Installation Notes

Install and operate this tap using a tapping machine, CNC machining center, or manual tap wrench appropriate for the shank diameter. Ensure the workpiece is securely fixtured before tapping. Apply a suitable cutting fluid for the workpiece material to optimize thread quality and tap life. Spiral point taps are intended for through-hole use — do not use in blind holes where chip evacuation is restricted.