Import BDNA-20788 5/16-24 Unf Bottoming Tap Hss

Product Description

The IMPORT BDNA-20788 is a straight flute bottoming tap designed for threading 5/16-24 UNF holes in a wide range of ferrous and non-ferrous materials. Built from high-speed steel (HSS) with a gold oxide coating, it delivers solid wear resistance and reduced friction during the cutting process. The bottoming chamfer allows threading to within one to two threads of a blind hole bottom, making it the right choice when full thread depth is required close to the base of a drilled hole. With four flutes and a right-hand H3 thread limit, this tap maintains consistent tolerance control suited to production and repair work alike.

This tap is used in machining, maintenance, and fabrication settings where 5/16-24 UNF internal threads are needed in blind or through holes. The bottoming style is especially common in repair scenarios where a plug or taper tap has already started the thread and the final passes must reach maximum depth. It is appropriate for use in machine tool operations, manual tapping handles, and drill press setups. Trade professionals in industrial maintenance, HVAC equipment fabrication, and general mechanical assembly will find this size common in equipment fastener applications.

Key Features

• Bottoming chamfer allows threading to near the bottom of blind holes
• High-speed steel construction provides durability across a range of workpiece materials
• Gold oxide coating reduces friction and improves chip evacuation
• 4 straight flutes for controlled chip flow in through and blind hole applications
• Right-hand H3 thread limit for consistent tolerance on 5/16-24 UNF threads

Compatibility

Designed as a standard replacement or general-use bottoming tap for 5/16-24 UNF thread applications in ferrous and non-ferrous materials using manual or machine tapping setups.

Installation Notes

Tapping should be performed by a machinist or qualified maintenance technician using proper cutting fluid to extend tool life and improve thread quality. Ensure the workpiece is securely clamped and the tap is aligned perpendicular to the drilled hole before beginning. For blind holes, clear chips regularly to prevent tap breakage. Follow applicable shop safety practices and use the correct tap wrench or machine holder for this tap size.