Wiseman Threading Tools Bottom Lead Metric HSS Tap - M18x2.5 is a dedicated left-hand thread tap designed for precise reverse-thread machining in metalworking projects. Built to ISO 529 standards, this tool delivers consistent thread profiles across standard practice materials when you need a reverse-threaded fastener or a left-hand component in your assembly. The tool is uncoated and ground for clean cutting action with predictable results, even in challenging metals.

• Thread direction and size: Metric M18 x 2.5, left-hand thread for reverse engagement.
• Lead style: Bottom lead (bottoming) design for full-depth threading to the bottom of blind holes.
• Material and finish: High-speed steel (HSS), ground thread, uncoated for versatile compatibility across common metals.
• Standards: ISO 529 specification ensures interchangeability with other ISO 529 taps and standard tapping practices.
• Applications: Ideal for repair or production tasks requiring left-hand threads—such as counter-rotating fasteners, specialty machinery, and reverse-assembly components.

Designed for machinists, hobbyists, and engineers who demand reliable left-hand tapping tools, this Wiseman tap integrates into hand tapping setups and small workshop rigs with standard tap wrenches. Its robust HSS composition provides enduring cutting edges and consistent thread form across multiple holes and projects.

Practical tips for best results

• Lubricate with a light tapping fluid to extend tool life and improve chip clearance.
• Start with a gentle touch to prevent cross-threading, then advance with steady, even turns.
• Use a proper tap wrench or guiding fixture to maintain alignment and prevent chatter, especially when working in tight or shallow pockets.
• For blind holes, the bottom lead ensures full thread depth without breaking through the far side.

Whether you’re fabricating a reverse-threaded fastener system, repairing a threaded insert, or completing a precision project that requires a left-hand M18x2.5 thread, this Wiseman bottom-lead HSS tap is built to perform consistently under real-world workshop conditions. The combination of left-hand geometry, ISO-standard dimensions, and a durable uncoated HSS form delivers dependable results across a wide range of metals and applications.