Accupro T4677545 Spiral Flute Tap 7/16-20 4 Flute Hss

Product Description

The ACCUPRO T4677545 is a spiral flute tap designed for threading 7/16-20 internal threads in production and maintenance applications. Built from 3% Vanadium High Speed Steel (HSS) with a nitride finish, it delivers solid wear resistance and edge retention across repetitive tapping cycles. The modified bottoming chamfer allows threading close to the bottom of blind holes, and the 4-flute, slow-helix spiral flute geometry evacuates chips upward efficiently. The H5 thread limit supports consistent fit tolerance. This tap is intended for use by machinists, tool-and-die technicians, and maintenance professionals working with ferrous materials.

The T4677545 is rated for cast iron applications. The right-hand flute and right-hand thread configuration is the standard orientation for conventional tapping operations. With an overall length of approximately 3-5/32 inches and a shank diameter of 8.20 millimeters, it fits standard tap holders and chucks used in both manual and CNC tapping setups. The 15-degree helix angle provides moderate chip clearance suited to shorter chip materials like cast iron. Coolant-through capability is not included on this tap.

Key Features

• 7/16-20 thread size with H5 thread limit for controlled fit tolerance
• Modified bottoming chamfer for threading near the base of blind holes
• 3% Vanadium HSS construction for improved wear resistance over standard HSS
• Nitride finish reduces friction and extends tool life in cast iron
• 4-flute spiral design evacuates chips away from the cutting zone
• Right-hand flute, right-hand thread — standard tapping orientation

Compatibility

Designed for tapping 7/16-20 unified fine (UNF) threads in cast iron workpieces. Fits standard tap holders sized for an 8.20-millimeter shank diameter.

Installation Notes

This tap should be installed by qualified machinists or maintenance technicians familiar with tapping operations. Secure the tap in a properly aligned tap holder or chuck to prevent cross-threading and tool breakage. Ensure the workpiece is firmly fixtured before beginning the tapping cycle. Apply appropriate cutting fluid for cast iron to extend tool life, even though this tap does not have a coolant-through design.