Wiseman Threading Tools presents the Second Lead Metric HSS Tap Left Hand – M20x2.5. This precision tool is engineered for reliable left-hand threading in metalworking, built from high-speed steel and ground for a clean, accurate thread form. Uncoated for versatile cutting performance, it adheres to ISO 529 dimensions so it fits standard holes and fittings with confidence.

Why this left-hand M20x2.5 tap stands out

• Left-hand thread, M20x2.5: specifically designed for reverse-thread fasteners and assemblies that tighten counterclockwise.
• Second lead (two-start): a two-start thread geometry that increases feed rate and reduces required turns, speeding up tapping without sacrificing thread accuracy.
• High-speed steel, ground finish: delivers precise flute geometry for cleaner cuts and efficient chip evacuation; uncoated for compatibility with cutting oils and standard machine setups.
• ISO 529 compliant: guaranteed dimensional accuracy across common metric tapping standards, ensuring reliable fit with standard components.
• USA Plug lead (USA Plug lead): designed for compatibility with typical US machine spindles and tapping setups.

Practical applications and how to use

This tap is ideal for general-purpose metalworking where left-hand threads are required—think reverse-threaded fasteners in mechanical assemblies, hobbyist projects, and repair work on equipment that employs left-handed fasteners. For best results, use a properly sized pre-drilled hole, lubricate with cutting oil, and advance with steady, even pressure. Because this is a two-start tool, start with the recommended hole size for M20x2.5 and allow the two-thread starts to engage quickly, then maintain consistent torque to avoid thread deformation.

What to expect in practice

With the Wiseman tap, you’ll notice smoother penetration into tougher metals than a single-lead tap, thanks to the enhanced lead and robust HSS core. The uncoated finish gives you the flexibility to apply your preferred lubricant and makes the tool easy to resharpen as needed. This is a dependable choice for shop benches and home workshops alike, offering dependable results without specialized coatings or exotic alloys.

Technical specifications

• Thread direction: Left-hand
• Size: M20x2.5
• Lead: Second lead (two-start) – approximate 5.0 mm lead
• Material: High-speed steel, ground
• Coating: Uncoated
• Standard: ISO 529
• Lead designation: USA Plug lead

Note: This description is based on the provided product title and description. For optimal results, pair this tap with appropriate drilling and lubrication practices and store in a dry environment to preserve its precision for repeated use.