The Wiseman Threading Tools Taper Lead Metric HSS Tap is a purpose-built internal-threading solution designed for durability and precision in metric sizes. Ground for accuracy and uncoated for predictable cutting performance, this right-hand tap follows ISO 529 dimensions and delivers a taper lead that makes starting threads smoother, especially in harder metals or tighter tolerances.

Why this taper lead HSS tap stands out

• Taper lead design: A gentle lead at the tip reduces chatter and cross-threading during entry, easing alignment and enabling cleaner thread formation from the first turn.
• High-speed steel, uncoated: Combines toughness with a straightforward cutting action. Uncoated surfaces work well with cutting fluids to manage heat and chip evacuation, giving you consistent results across jobs.
• ISO 529 compliant, metric M39x4: Precisely engineered to standard metric specifications, ensuring compatibility with common internal-thread applications that require a robust M39x4 thread profile.
• Right-hand thread: The most common threading direction for load-bearing components, making this tap versatile for a wide range of assemblies and repairs.
• Ground accuracy: Carefully ground threads provide a smoother cut and better final thread quality, reducing the need for rework.

Ideal use cases

Design engineers, machinists, and maintenance professionals will reach for this tap when creating or repairing large metric threads in steel, cast iron, or other metals where a strong, dependable internal thread is required. It’s particularly well-suited for:

• Automotive and heavy machinery components that demand durable M39x4 threads
• Repair work on gear housings, housings, and engine blocks where reliable engagement matters
• Prototype and production settings where precision metric threading is essential

How to use for best results

• Drill a properly sized pilot hole for M39x4, following the manufacturer’s recommendations for your material and hole depth.
• Apply a quality cutting fluid or oil to reduce friction and carry away chips.
• Align the tap accurately with the hole and begin with light, steady pressure to engage the threads.
• Turn forward a partial turn, then back off slightly to break chips. Repeat, advancing gradually while maintaining perpendicular alignment.
• Periodically back the tap out to clear chips, and finish with a gentle pass to ensure clean threads.

Practical considerations and care

• Use a tap wrench or machine tapping setup to maintain straight, controlled alignment. Avoid forced entry that can bend the flutes.
• Keep the tap clean and dry when not in use to preserve edge precision.
• Store with other Wiseman threading tools to protect the tip and flutes from damage.
• Choose cutting fluid suitable for the material being threaded and the equipment used (manual or machine tapping).

Specifications at a glance

• Product: Wiseman Threading Tools Taper Lead Metric HSS Tap
• Size: M39 x 4
• Thread direction: Right-hand
• Lead: Taper lead
• Material: High Speed Steel (HSS)
• Finishing: Uncoated
• Standard: ISO 529
• Application: Internal threads in metric sizes

When you need a dependable, metric thread-cutting tool that starts easily, maintains accuracy, and supports demanding projects, the Wiseman HSS Tap in M39x4 is a reliable choice that helps you achieve clean, strong threads with fewer passes and less rework.