Osg 1242600 Spiral Point Plug Tap 1/2-20 Unf Hss

Product Description

The OSG 1242600 is a spiral point plug tap designed for threading 1/2-20 UNF internal threads in a wide range of ferrous and non-ferrous materials. Built from high-speed steel with a bright finish, it features a 3-flute spiral point geometry that pushes chips forward ahead of the cutting zone, keeping the flutes clear during through-hole tapping operations. The plug chamfer provides a gradual lead-in for controlled thread engagement. With an H5 thread limit and a 2B class of fit, this tap produces threads within standard tolerance for most general-purpose fastener applications. Machinists, tool and die makers, and maintenance technicians rely on this tool for consistent thread quality in production and repair settings.

The 1242600 is suited for through-hole tapping in aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, high-carbon steel, and hardened steel. The spiral point design makes it especially effective in materials that produce long, stringy chips, since the geometry actively directs chips out of the cutting path. It is appropriate for both CNC and manual tapping operations where through-hole access is available.

Key Features

• Spiral point geometry pushes chips forward for unobstructed through-hole tapping
• High-speed steel construction supports a broad range of workpiece materials including hardened steel
• Plug chamfer provides gradual thread engagement and reduces tap breakage risk
• H5 thread limit and 2B class of fit for standard general-purpose thread tolerance
• Right-hand thread direction; no coolant-through required
• Bright finish with no coating — suitable for use with standard cutting fluids

Compatibility

Designed for through-hole tapping of 1/2-20 UNF threads in aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, high-carbon steel, and hardened steel workpieces.

Installation Notes

Secure the workpiece firmly before tapping; any movement during operation increases the risk of tap breakage. Use an appropriate cutting fluid for the workpiece material and apply consistent, even feed pressure — never force a tap. For manual tapping, use a calibrated tap wrench sized for the shank diameter. Back the tap out periodically to break chips when working in deeper holes, even in through-hole applications with tougher materials.