Irwin IR8145 Plug Tap 1/2-20 Unf 4-flute

Product Description

The IRWIN IR8145 is a 1/2-20 UNF plug-style hand threading tap designed for cutting internal threads in metal workpieces. It features a straight flute geometry with four flutes and a right-hand direction of cut. The 3-to-5-thread chamfer point style makes it a true plug tap, suited for threading through holes and most standard tapping applications. Manufactured from high carbon steel (HCS), it delivers reliable thread form and durability across typical hand-tapping tasks. This tap is driven by a hand wrench or tap handle and does not require a machine setup.

This plug tap is used in maintenance, repair, and fabrication work where 1/2-20 UNF internal threads must be cut or restored. The 1/2-20 UNF designation indicates a half-inch major diameter with 20 threads per inch on a Unified National Fine thread form. Fine-thread taps like this one are commonly used in automotive, HVAC, plumbing fixture, and general mechanical assemblies where finer thread engagement and reduced thread stripping risk are priorities. It is appropriate for hand-tapping steel, iron, and similar materials in shop or field settings.

Key Features

• 1/2-20 UNF thread form for fine-pitch internal thread cutting
• Plug style with 3-to-5-thread chamfer for standard through-hole and most blind-hole applications
• Four straight flutes for clean chip evacuation in common metals
• Right-hand cut direction compatible with standard tap handles and wrenches
• High carbon steel (HCS) construction for hand-tapping durability
• Carded packaging for individual retail or toolbox storage

Compatibility

Designed for use with standard 1/2-20 UNF thread specifications in hand-tapping applications using a compatible tap wrench or T-handle tap driver.

Installation Notes

This tap is intended for hand operation by a machinist, mechanic, or qualified trade professional using a tap wrench. Always drill the correct tap drill size for 1/2-20 UNF before tapping to avoid tap breakage. Apply appropriate cutting fluid to extend tap life and improve thread quality. Keep the tap aligned perpendicular to the workpiece surface throughout the operation.

Technical Specifications

• Thread Size: 1/2-20
• Thread Form: UNF (Unified National Fine)
• Tap Style: Plug
• Point Chamfer: 3 to 5 threads
• Number of Flutes: 4
• Flute Type: Straight
• Direction of Cut: Right hand
• Drive Type: Hand wrenching
• Material: High carbon steel (HCS)
• UPC: 042526081453

Standard Information

• Brand: IRWIN
• Manufacturer Part Number: IR8145