Import BDNA-20681 Tap Set 5/16-24 Unf 3 Piece Hss

Product Description

The IMPORT BDNA-20681 is a 3-piece tap set designed for cutting 5/16-24 UNF internal threads in metal workpieces. The set includes bottoming, plug, and taper taps, allowing machinists and trade professionals to progress through thread-cutting stages in a single kit. All three taps are ground from high-speed steel (HSS) and finished with a gold oxide coating that provides light lubricity and corrosion resistance during use. Each tap features 4 flutes for efficient chip evacuation. Overall length is 2-23/32 inches, and the thread limit is H3, indicating a tolerance class suited for standard UNF fastener fitment.

This tap set is used wherever 5/16-24 UNF threaded holes must be cut or restored in ferrous and non-ferrous metals. Typical applications include repair and fabrication work in HVAC equipment, plumbing fixture assemblies, electrical panel hardware, and general mechanical service. The three-tap progression — taper, plug, then bottoming — allows threading to the bottom of a blind hole, making this set particularly useful in close-tolerance repair scenarios where full thread depth is required.

Key Features

• 3-piece set includes taper, plug, and bottoming taps for complete thread-cutting progression
• 5/16-24 UNF thread form for fine-pitch applications
• High-speed steel construction for durability in ferrous and non-ferrous materials
• 4-flute geometry for efficient chip removal during cutting
• Gold oxide finish provides light lubricity and corrosion protection
• H3 thread limit for consistent tolerance in standard UNF fastener fitment

Compatibility

Designed for cutting or restoring 5/16-24 UNF internal threads in applications requiring a fine-pitch, straight-flute tap in high-speed steel.

Installation Notes

Thread cutting with this tap set should be performed by a qualified machinist or trade professional using appropriate cutting fluid to reduce heat and extend tool life. Always secure the workpiece before tapping and use a calibrated tap wrench or machine holder to maintain proper alignment and prevent tap breakage. Back off the tap periodically to break and clear chips, especially in blind holes. Follow applicable shop safety and OSHA standards when operating cutting tools.