Hertel R867179 Extension Tap 3/4-10 Hss Spiral Point

Product Description

The HERTEL R867179 is a spiral point plug extension tap designed for threading 3/4-10 UNC holes in production and maintenance machining applications. Built from high speed steel with a bright uncoated finish, it delivers reliable performance in a range of ferrous and non-ferrous materials. The spiral point geometry pushes chips ahead of the tap and into the hole, keeping the flutes clear and reducing the risk of chip-related breakage. At 8 inches overall length, the extension body provides reach into deep or recessed bores that standard-length taps cannot access. Three flutes and an H3 thread limit tolerance make it suitable for tapping standard to slightly oversized fits.

This tap is used in machining environments where threading operations require extended reach, such as deep bosses, recessed flanges, or blind setups accessed through a fixture. The plug chamfer style makes it appropriate for through-hole threading or starting threads in holes with adequate runout clearance. A reduced shank allows it to be held in standard collet chucks or tap holders sized for smaller shanks, expanding its compatibility with common tool holders on manual and CNC machines.

Key Features

• Spiral point geometry pushes chips forward, reducing clogging in through-hole applications
• 8-inch overall length provides extended reach for deep or recessed threading
• H3 thread limit tolerance for standard to slightly open fits on 3/4-10 UNC threads
• High speed steel construction for durability across a broad range of workpiece materials
• Reduced shank for compatibility with smaller-bore collet chucks and tap holders
• Bright uncoated finish suitable for use with cutting fluids in general-purpose tapping

Compatibility

Designed as a standard extension tap for through-hole 3/4-10 UNC threading operations using collet chucks, tap holders, or floating tap adapters that accept a reduced shank. Confirm holder bore and drive specifications before installation.

Installation Notes

Extension taps of this type are installed by qualified machinists or tool and die professionals. Ensure the workpiece is securely fixtured and the tap is properly aligned to the hole axis before starting the threading cycle. Use an appropriate cutting fluid or tapping oil for the workpiece material to extend tool life and improve thread finish. On CNC equipment, verify spindle speed and feed rate are set for the tap pitch and material before the cycle begins.