Wiseman Threading Tools Spiral Point Metric HSS Tap Left Hand - M20x2.5 is a purpose-built internal threading solution for metalworking professionals and serious hobbyists who demand reliable, precise left-hand threads. Forged from high-speed steel and ground to exacting ISO 529 dimensions, this tap delivers controlled, consistent cutting performance in standard through-holes without the need for coatings that can wear unevenly in aggressive tapping sessions. What makes this tap stand out - Left-hand thread, M20x2.5: Specifically designed to cut left-handed internal threads, ideal for assemblies where fasteners tighten in the reverse direction to prevent loosening under vibration. - Spiral point (gun nose) geometry: The forward-cutting tip drives chips ahead of the tap and out of the hole, reducing clogging and improving productivity in through-hole applications. - Uncoated HSS, general-purpose: A robust, affordable choice for everyday threading tasks across common metals like steel, cast iron, and aluminum. No coating means easy re-sharpening and straightforward inspection of the tool’s geometry. - Precision ground and ISO 529 compliant: Ensures reliable thread form, compatibility with standard nuts and accessories, and predictable results across jobs. - Right tool for the job in tight tolerances: The combination of spiral point design and left-hand threading makes it an excellent option when orientation and anti-rotation considerations matter in a machine or fixture. Who this is for - Machinists, engineers, and workshop pros who routinely create internal threads in left-handed configurations. - Projects that require secure, anti-rotation threaded joints in through-holes, such as bespoke machinery mounts, certain automotive assemblies, or gear housings. - Makers seeking a durable, repair-friendly tapping solution that performs well across mild to moderate threading tasks without specialty coatings. How to get the best results - Use appropriate cutting fluid or tapping oil to maximize tool life and achieve cleaner thread forms. - Start with a clean, deburred hole and a properly sized pilot drill to ISO 529 recommendations for M20x2.5 left-hand threads. - Apply steady, moderate torque with a suitable tap wrench or holder; avoid excessive feed pressure to prevent chatter or premature wear. - Post-tap deburring ensures a smooth bore and mating hardware seating, especially important for high-load or precision assemblies. Practical use cases and outcomes - Create durable left-handed internal threads in control housings, brake components, or hydraulic fittings where reverse-threaded fasteners prevent loosening during operation. - Achieve repeatable thread quality in prototype and production runs, thanks to the tap’s standardized ISO dimensions and reliable spiral-point cutting action. - A versatile general-purpose tool in metalworking shops that reduces the need for multiple specialized taps, while delivering dependable results time after time. In short, the Wiseman M20x2.5 Left-Hand Spiral Point HSS Tap is a focused, reliable choice for left-handed internal threads in through-holes. Its spiral-point design, uncoated HSS construction, and ISO-compliant geometry deliver precise threads, efficient chip evacuation, and practical value in everyday metalworking tasks.