Osg 1171002 Straight Flute Tap 5/16-24 Unf Hss

Product Description

The OSG 1171002 is a straight flute tap designed for cutting internal 5/16-24 UNF threads in a range of ferrous and non-ferrous materials. Built from high-speed steel (HSS), this tap features a plug chamfer, which provides a gradual thread start over several leading threads, making it well-suited for through-hole applications. It runs a 3B class of fit with an H3 thread limit, delivering the tight tolerances required for standard UNF fastener assemblies. Three straight flutes provide chip clearance in shorter-chipping materials. Overall length is 2-23/32 inches with a thread length of 1-1/8 inches. Installation is performed by machinists and maintenance trades using a tap wrench or CNC tapping head.

This tap is intended for through-hole tapping operations in general machining, maintenance, and repair environments. Compatible material applications include aluminum, cast aluminum, cast iron, high-carbon steel, low-carbon steel, and medium-carbon steel. It is well-matched to production and job-shop settings where UNF threaded holes are required in structural components, fixtures, or mechanical assemblies. The straight flute geometry keeps the tool simple and reliable in short-chipping materials where chip packing is not a concern.

Key Features

• 5/16-24 UNF right-hand thread form for standard unified fine-thread applications
• Plug chamfer provides gradual thread engagement over several leading threads - suited for through holes
• High-speed steel construction offers good wear resistance across a range of workpiece materials
• H3 thread limit and 3B class of fit meet standard UNF tolerance requirements
• 3 straight flutes promote chip clearance in short-chipping materials including cast iron and aluminum
• Compact overall length of 2-23/32 inches suitable for confined-access tapping

Compatibility

Designed for tapping 5/16-24 UNF through holes in aluminum, cast aluminum, cast iron, high-carbon steel, low-carbon steel, and medium-carbon steel workpieces. Compatible material applications are as specified by OSG for Series 103.

Installation Notes

This tap should be used by qualified machinists or maintenance technicians familiar with thread-cutting operations. Always secure the workpiece and ensure the tap is properly aligned to the drilled pilot hole before applying torque to prevent tap breakage or cross-threading. Apply appropriate cutting fluid for the workpiece material to extend tap life and improve thread quality. For power tapping, use a tapping head with torque limiting to avoid overloading the tool.