Osg 1681700 Straight Flute Tap 3/4-20 Unef Plug Hss

Product Description

The OSG 1681700 is a straight flute plug tap designed for cutting 3/4-20 UNEF right-hand internal threads in a range of ferrous and non-ferrous materials. Built from high-speed steel (HSS) with a bright, uncoated finish, this tap features 6 flutes and an H3 thread limit, making it well suited for producing accurate threads in through-hole and blind-hole applications where chip control is manageable. With an overall length of 4.25 inches and a thread length of 1.5 inches, it fits standard tap holders and machines used in production and maintenance environments. Licensed machinists, tool and die makers, and maintenance mechanics are the primary users of this tool.

This tap is used in general machining, metalworking, and maintenance, repair, and operations (MRO) applications. The plug chamfer style, with a moderate lead-in, makes it appropriate for starting threads in through holes or for following a taper tap in blind holes. It is suited for use in both manual tapping and machine tapping setups. This tap does not support coolant-through delivery, so external cutting fluid application is recommended when working with harder materials.

Key Features

• 3/4-20 UNEF thread form with H3 thread limit for consistent tolerance control
• 6-flute design provides good thread finish and distributes cutting load across multiple edges
• Plug chamfer provides a moderate lead-in suitable for through holes and follow-up blind-hole tapping
• High-speed steel construction offers durability across a range of workpiece materials
• Bright, uncoated finish allows visual inspection of tool condition during use
• Right-hand thread direction, standard for most general tapping applications

Compatibility

Rated for use in aluminum, cast aluminum, cast iron, high-carbon steel, low-carbon steel, and medium-carbon steel workpieces. Fits standard tap holders sized for a 0.59-inch shank diameter and 0.442-inch square drive.

Installation Notes

Tapping should be performed by a qualified machinist or maintenance mechanic using a properly sized tap wrench, tapping head, or CNC tapping cycle. Always apply an appropriate cutting fluid for the workpiece material to reduce heat and extend tool life. Secure the workpiece firmly before beginning to prevent movement during thread cutting. Reverse the tap periodically to break chips when working in deeper holes.