Osg 1240001 Spiral Point Tap 1/4-20 Unc Hss Plug

Product Description

The OSG 1240001 is a spiral point tap designed for cutting right-hand internal threads in through-hole applications. Built from high-speed steel with a steam oxide coating, this 1/4-20 UNC tap features a plug chamfer and two flutes that push chips forward ahead of the cutting edge, keeping the flutes clear during the tapping operation. It is sized for a 2B class of fit with an H5 thread limit, making it suitable for standard tolerance threaded fastener applications. The overall length is 2.5 inches with a thread length of 0.638 inches and a shank diameter of 0.255 inches. Machinists, maintenance technicians, and tool-and-die tradespeople are the primary users of this tap.

The OSG 1240001 is suited for through-hole tapping in a broad range of ferrous and non-ferrous metals. The material application list includes aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, high-carbon steel, and hardened steel. The plug chamfer style requires a pre-drilled hole and is the standard choice for general production and maintenance tapping where thread engagement must begin partway through the chamfered lead. This tap is not designed for blind-hole applications where chip clearance at the bottom of the bore is a concern.

Key Features

• Spiral point geometry pushes chips forward through the hole, reducing clogging in through-hole tapping
• High-speed steel construction provides toughness across a wide range of workpiece materials
• Steam oxide coating reduces friction and provides mild lubricity during cutting
• H5 thread limit and 2B class of fit deliver standard tolerance internal threads
• Plug chamfer with 2 flutes suits general-purpose production and maintenance tapping
• No coolant-through feature keeps the design simple for use with cutting fluid applied externally

Compatibility

Designed as a standard 1/4-20 UNC spiral point tap compatible with conventional tap handles, tapping heads, and CNC machine tool holders accepting a straight shank of 0.255 inches diameter.

Installation Notes

This tap is installed by machinists and maintenance technicians using a tap wrench, tapping head, or CNC rigid-tapping spindle. The workpiece must be secured and the correct tap drill size for 1/4-20 UNC used to prepare the through-hole before tapping. Apply cutting fluid appropriate to the workpiece material before and during the tapping operation. Do not force the tap if resistance increases unexpectedly - back off to break and clear chips before continuing.