Osg 1012502 Straight Flute Tap 4-48 Unf Plug 2B Hss

Product Description

The OSG 1012502 is a straight flute plug tap designed for cutting internal 4-48 UNF threads in a wide range of metals. Built from high-speed steel, this tap delivers consistent thread form and tool life across production and maintenance tapping operations. It runs 3 flutes in a straight configuration, which helps channel chips away from the cutting zone in through-hole and shallow blind-hole applications. The plug chamfer provides a gradual lead-in over several threads, making it well suited for starting and completing threads with a single tap pass. Overall length is 1-7/8 inches, with a 9/16 inch thread length and an H2 thread limit for controlled tolerance fitment.

This tap is intended for use by machinists, maintenance technicians, and tool-room professionals threading small-diameter fastener holes. The 4-48 UNF thread form is common in precision assemblies, instrument panels, and light mechanical hardware where fine thread pitch provides higher tensile engagement in thin or soft material. Rated for use in aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, and high-carbon steel, this tap covers the majority of material types encountered in general machining and repair work. The right-hand thread direction matches standard fastener convention in these applications.

Key Features

• 4-48 UNF thread form with 3 straight flutes for efficient chip clearance
• Plug chamfer provides gradual lead-in for single-pass thread cutting
• H2 thread limit ensures consistent fit within standard 2B class-of-fit tolerance
• High-speed steel construction supports use across ferrous and non-ferrous materials
• Right-hand thread direction, no coolant-through requirement
• Compact 1-7/8 inch overall length suits tight-clearance setups

Compatibility

Designed for tapping 4-48 UNF internal threads in aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, and high-carbon steel workpieces. The 2B class of fit is compatible with standard 2A-class external fasteners.

Installation Notes

This tap should be installed in a tap wrench, tapping head, or CNC rigid-tap holder appropriate for the shank size. Always use a cutting fluid or tapping compound matched to the workpiece material to extend tool life and improve thread finish. Secure the workpiece fully before tapping to prevent movement that can break small-diameter taps. Inspect the tap for chipping or wear before each use, and replace if cutting edges show visible damage.