8145 Fractional Tap, 1/2-in. X 20 Nf, Plug Tap

The Irwin 8145 is a hand-threading tap designed for routine maintenance, repair work, and rethreading applications where high accuracy and tight thread tolerance are not critical. This fractional plug tap cuts a 1/2-inch by 20 National Fine (NF) thread and works in a variety of materials, making it a versatile choice for general-purpose threading tasks.

With four straight flutes ground to provide rapid chip removal, this tap enables efficient threading and simplified manual operation. The design supports hand-threading work and produces a Class 2B thread suitable for most maintenance and repair jobs. When used with the recommended 29/64-inch drill bit, this tap delivers reliable performance for bolt hole rethreading and similar applications.

Features and Benefits

• Four Straight Flutes: Ground design provides rapid chip removal for efficient, trouble-free threading in a range of materials.
• Class 2B Thread Production: Produces threads that meet Class 2B specifications, ideal for general maintenance and repair work rather than precision applications.
• Manual Threading Simplified: Well-balanced design makes hand-threading work straightforward and accessible for routine tasks.
• High Carbon Steel Construction: HCS material provides durability and reliable performance in routine threading tasks.
• Plug Tap Design: Suited for routine maintenance, repair work, and rethreading where high accuracy and tight tolerance thread are not critical.

Specifications

• Brand: Irwin
• Model: 8145
• Thread Size: 1/2 inch - 20 National Fine (NF)
• Tap Type: Plug Tap
• Flutes: 4-flute straight flute design
• Material: High Carbon Steel (HCS)
• Thread Class: Class 2B
• Recommended Drill Bit: 29/64 inch

How to Use

Drill a 29/64-inch hole into your workpiece, then insert this tap and turn it by hand to cut the thread. This tap is suited for routine maintenance, repair work, and rethreading where high accuracy and tight tolerance thread are not critical requirements.