Osg 1302002101 Spiral Flute Tap 5/16-24 Unf Bottoming Hss

Product Description

The OSG 1302002101 is a spiral flute bottoming tap designed for threading 5/16-24 UNF holes in a wide range of metallic workpiece materials. Built from high-speed steel with a steam oxide coating, it produces right-hand internal threads to a 3B class of fit with an H3 thread limit. The 45-degree helix angle drives chips up and out of the hole during the cut, making this tap well suited for blind-hole applications where chip evacuation is critical. At 2.719 inches overall length with a thread length of 0.444 inches, it fits standard tap handles and CNC tapping chucks used in production and maintenance machining environments. Machinists, tool-and-die makers, and maintenance technicians are the primary users.

This tap is suited for threading blind holes in aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, and high-carbon steel. The bottoming chamfer allows threads to be cut to the bottom of a blind hole, a requirement common in fixture, tooling, and general machining work where full thread depth is needed with minimal clearance at the bottom of the bore. It is part of OSG Series 13020.

Key Features

• Spiral flute design at 45-degree helix angle for reliable upward chip evacuation in blind holes
• Bottoming chamfer allows threading to the bottom of blind holes
• High-speed steel construction provides toughness and wear resistance across common metallic materials
• Steam oxide coating reduces friction and improves chip flow during tapping
• H3 thread limit and 3B class of fit for standard tolerance internal threading
• Right-hand flute direction and right-hand thread for conventional tapping setups

Compatibility

Designed for 5/16-24 UNF threading applications in aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, and high-carbon steel workpieces. Coolant-through feature is not included on this tap.

Installation Notes

This tap is installed and operated by a qualified machinist using a tap handle, tapping head, or CNC rigid tapping cycle. Ensure the spindle speed and feed rate are appropriate for the workpiece material and tap size before starting. Use a compatible cutting fluid or tapping compound to extend tool life and improve thread finish. Inspect the tap for wear or chipping before each use and replace if damage is observed to avoid thread quality issues or tap breakage.