Osg 1137600 Straight Flute Plug Tap 1-1/4-7 Unc Hss

Product Description

The OSG 1137600 is a straight flute plug tap designed for cutting 1-1/4-7 UNC internal threads in a range of ferrous and non-ferrous materials. Built from high-speed steel (HSS) with a bright, uncoated finish, this tap delivers consistent thread form across production and maintenance applications. It features 4 flutes, a plug chamfer for general-purpose through-hole and blind-hole threading, and an H4 thread limit for a 3B class of fit. With an overall length of 5-3/4 inches and a thread length of 2-9/16 inches, it fits standard tap holders and machine spindles used by machinists and maintenance technicians.

This tap is suited for threading operations in job shops, manufacturing facilities, and industrial maintenance environments. It handles aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, and high-carbon steel. The plug chamfer style makes it the standard choice when starting a tap in a pre-drilled hole where the thread does not need to be cut to the very bottom. It is appropriate for both hand tapping and machine tapping setups where a straight-flute tool is specified.

Key Features

• Thread size 1-1/4-7 UNC with right-hand thread direction
• 4 straight flutes with plug chamfer for general-purpose through-hole and blind-hole use
• High-speed steel construction for durability across carbon and alloy steel applications
• H4 thread limit ensures consistent 3B class of fit tolerances
• Bright, uncoated finish suitable for use with cutting fluids across a broad material range
• No coolant-through feature — compatible with flood or brush-applied cutting fluid

Compatibility

Designed for use in materials including aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, and high-carbon steel. Fits standard tap holders sized for a 1.21-inch shank diameter. Compatible with both hand tapping and CNC or manual machine tapping operations calling for a straight-flute plug tap in 1-1/4-7 UNC.

Installation Notes

A licensed machinist or qualified maintenance technician should perform tapping operations. Ensure the workpiece is securely fixtured and the tap is properly aligned with the pre-drilled pilot hole before starting. Apply an appropriate cutting fluid for the material being tapped to extend tool life and improve thread finish. Do not force a tap that has stalled — back it out to clear chips before continuing.