Meet the Wiseman Threading Tools Bottom Lead Metric HSS Tap Left Hand – a precision internal threading solution engineered for metric M20x2.5 workpieces. This high-speed steel, ground-thread tap arrives uncoated for reliable heat resistance and consistent cutting action, making it a dependable choice for general-purpose tapping in metalworking projects.

Why this HSS left-hand tap stands out

• Left-hand thread, right-angle application: Specifically designed for reverse-threaded components and applications requiring a left-hand engagement, ensuring clean, accurate threads whether you’re assembling or disassembling parts.
• Metric accuracy based on ISO 529: The M20x2.5 thread form adheres to ISO 529 tolerances, delivering standardized, interchangeable results across compatible fasteners and housings.
• Bottom lead geometry: Optimized lead design promotes controlled entry and steady chip evacuation, reducing chatter and aiding starting accuracy in deeper or blind holes.
• High-speed steel, ground finish: The HSS material provides toughness and wear resistance, while the precision ground threads ensure smooth cutting action and accurate thread form from start to finish.
• Uncoated, general purpose: An affordable, versatile option that performs well in a broad range of metal substrates without the extra cost or heat buildup of coatings.

Ideal use cases

• Tapping internal threads in steel, cast iron, or alloy components where a left-hand fastener is required.
• Repair and maintenance tasks on machinery, automotive assemblies, or bespoke projects that rely on metric M20x2.5 left-handed threads.
• Prototyping and small-batch production where quick tooling and dependable performance are essential.

How to achieve the best results

1. Secure the workpiece firmly in a vice or on a tapping platform. Use a compatible tapping chuck or tap handle designed for internal threads.
2. Apply a quality cutting fluid or anti-seize lubricant to reduce friction and extend tool life.
3. Begin with a light, steady turn to establish the thread engagement. Maintain consistent pressure and avoid forcing the tap.
4. When full thread depth is reached, back the tap out slowly to clear chips and prevent cross-threading or binding.

What you’ll appreciate in your workshop

For metalworkers who demand reliability and precision, this Wiseman HSS left-hand tap delivers predictable performance in metric threads. The combination of ISO 529 compliance, bottom lead design, and uncoated HSS construction creates a practical, durable tool that fits naturally into standard tapping workflows. Whether you’re restoring a piece of equipment or fabricating a new component with a left-handed thread, this tap provides confident control and a clean thread every time.

Specifications at a glance

• Tool type: Threading tap
• Material: High-speed steel (HSS)
• Finish: Uncoated
• Thread form: Metric M20x2.5
• Thread direction: Left-hand
• Lead: Bottom lead
• Standards: ISO 529 dimensions