Accupro T2644543 Spiral Flute Tap 7/16-20 3 Flute

Product Description

The ACCUPRO T2644543 is a spiral flute tap designed for threading 7/16-20 (UNF) holes in aluminum and similar materials. It features three right-hand flutes with a 40-degree helix angle and a modified bottoming chamfer, allowing it to cut threads close to the bottom of a blind hole. The tap is manufactured from 3% vanadium high-speed steel and carries a bright/uncoated finish. The H3 thread limit designation indicates a controlled tolerance suitable for standard unified fine-thread applications. Overall length is 3 inches with a thread length of 18 millimeters and an 8.20-millimeter shank diameter.

This tap is suited for production and maintenance threading in aluminum workpieces where a fine unified thread is required. The modified bottoming chamfer reduces the lead-in distance compared to a plug tap, making it practical for blind holes with limited thread runout. The fast flute style promotes efficient chip evacuation when threading ductile materials. Machinists, toolroom operators, and maintenance technicians working in aerospace, automotive, and general manufacturing environments will encounter this application regularly.

Key Features

• Modified bottoming chamfer for threading close to the bottom of blind holes
• 40-degree right-hand helix angle for fast, efficient chip evacuation in aluminum
• 3% vanadium high-speed steel construction for wear resistance and edge retention
• H3 thread limit for consistent tolerance control in 7/16-20 UNF applications
• Bright/uncoated finish — no coating buildup affecting thread tolerance
• Coolant-through: No — suitable for conventional flooded or dry tapping setups

Compatibility

Designed for cutting 7/16-20 UNF right-hand threads in aluminum. The H3 thread limit and 8.20-millimeter shank diameter are compatible with standard tap holders and collet chucks sized for that shank diameter.

Installation Notes

This tap should be installed by a qualified machinist or toolroom technician familiar with threading operations. Ensure the workpiece is securely fixtured and the spindle is aligned axially with the drilled hole before beginning the tapping cycle. Use an appropriate cutting fluid rated for aluminum when operating at production speeds. Inspect the tap for chipping or wear before each use, and never reverse a broken tap with power — extract manually using an appropriate extractor.