Osg 1662700 Straight Flute Tap 5/8-18 Unf Left Hand Hss

Product Description

The OSG 1662700 is a straight flute tap designed to cut 5/8-18 UNF internal left-hand threads in a range of ferrous and non-ferrous materials. Built from high-speed steel with a bright/uncoated finish, it features 4 flutes and a plug chamfer, making it suited for through-hole tapping applications where chip evacuation proceeds in a straight path. The H3 thread limit provides a controlled tolerance fit for Class 3B thread accuracy. At 3-13/16 inches overall length with a 1-13/16 inch thread length, this tap is sized for standard hand or machine tapping operations performed by machinists and maintenance professionals.

The 1662700 is intended for use in materials including aluminum, cast aluminum, cast iron, high-carbon steel, low-carbon steel, and medium-carbon steel. The left-hand thread direction makes it the correct choice when tapping holes that require reverse-thread fasteners, such as those used on rotating assemblies where standard right-hand threads would self-loosen. The plug chamfer style requires a pre-drilled through hole and is not suited for blind-hole applications where a bottoming tap would be required. This tap is part of OSG Series 101L and is appropriate for both manual and CNC tapping setups.

Key Features

• Left-hand thread direction for reverse-thread hole applications
• 4-flute straight design for consistent chip flow in through-hole tapping
• Plug chamfer style for standard through-hole entry
• H3 thread limit for Class 3B fit tolerance control
• High-speed steel construction compatible with steel and aluminum workpieces
• Bright/uncoated finish suitable for use with cutting fluid on a broad range of base materials

Compatibility

Designed for tapping 5/8-18 UNF left-hand threaded holes in aluminum, cast aluminum, cast iron, high-carbon steel, low-carbon steel, and medium-carbon steel workpieces. Part of OSG Series 101L.

Installation Notes

This tap is installed by machinists or maintenance technicians using a tap wrench, tapping head, or CNC rigid tapping cycle. Ensure the workpiece is securely fixtured and the pilot hole diameter matches the correct tap drill size for 5/8-18 UNF before beginning. Apply appropriate cutting fluid for the workpiece material to extend tool life and improve thread finish. Because this is a left-hand tap, spindle direction must be reversed from standard tapping procedures when used on power equipment.