Osg 1241001 Spiral Point Tap 5/16-18 Unc Hss Oxide

Product Description

The OSG 1241001 is a spiral point tap designed to cut 5/16-18 UNC internal threads in through-hole applications. Built from high-speed steel with a steam oxide coating, this plug-chamfer tap drives chips forward ahead of the cutting edge, keeping the flute path clear during production tapping. It runs 3 flutes, carries an H5 thread limit, and meets a 2B class of fit - the standard tolerance for most general-purpose threaded fastener applications. Overall length is 2.719 inches with a thread length of 1.125 inches. Licensed machinists, toolmakers, and maintenance technicians install this tap in manual drill presses, CNC machining centers, and tapping arms.

This tap is suited for through-hole tapping in a wide range of ferrous and non-ferrous materials. The steam oxide finish reduces friction and provides light corrosion resistance, making it a practical choice for production runs and maintenance work alike. Confirmed material applications include aluminum, cast aluminum, cast iron, hardened steel, high-carbon steel, low-carbon steel, and medium-carbon steel. The plug chamfer profile - typically 3 to 5 threads of chamfer lead - makes this tap well suited to through-hole threading where chip evacuation ahead of the tap is the priority over bottom-of-hole reach.

Key Features

• Spiral point geometry pushes chips forward, reducing clogging in through-hole applications
• High-speed steel construction handles a broad range of workpiece materials including hardened steel
• Steam oxide coating lowers friction and extends tool life in dry or lightly lubricated tapping
• H5 thread limit and 2B class of fit meet standard fastener assembly tolerances
• Right-hand thread direction, plug chamfer - compatible with standard tapping equipment and tap holders
• 3 flutes provide a balance of chip room and cutting edge support

Compatibility

Designed for use in standard straight-shank tap holders, tapping chucks, and floating tap holders that accept a 0.318-inch shank diameter. Suitable for manual and CNC through-hole tapping operations in the materials listed above.

Installation Notes

Installation should be performed by a qualified machinist or maintenance technician using appropriate cutting fluid or tapping compound for the workpiece material. The workpiece must be securely fixtured before tapping begins. Ensure the tap is properly aligned with the drilled pilot hole to prevent tap breakage. Never reverse-run a spiral point tap to break chips - the forward chip ejection design is intended for continuous through-hole passes.