Why must machine-used ST threading taps possess torsional strength for automated tapping?
Publish Time: 2025-10-01
In modern mechanical manufacturing, threaded connections are one of the most widely used assembly methods. With the widespread adoption of industrial automation and CNC machining technology, tapping operations have shifted from traditional manual labor to automated processes performed by equipment such as drilling and tapping centers, CNC machining centers, and specialized tapping machines. In this context, machine-used ST threading taps, as core cutting tools, must meet performance requirements far exceeding those of manual taps. High torsional strength is a key indicator of a machine tap's suitability for automated production. Insufficient torsional strength can easily lead to tap breakage, thread failure, and even damage to the machine tool spindle, resulting in significant economic losses.
1. The "unmanned" nature of automated tapping creates high risks.
Unlike manual tapping, the automated tapping process is program-controlled and runs continuously once started, leaving the operator with no real-time visibility into the cutting status. If the tap suddenly encounters resistance during thread entry due to uneven material hardness, misaligned hole placement, or insufficient cooling, torque can increase dramatically. Ordinary taps are prone to plastic deformation or instantaneous breakage under high torque. In unmanned automated production lines, a broken tap not only blocks the workpiece thread hole and disrupts cycle time, but may also require downtime for disassembly, tool replacement, and debris removal. In severe cases, the workpiece must be reworked, significantly reducing production efficiency. Therefore, machine taps must possess sufficient torsional strength to withstand unexpected high loads and ensure a stable and reliable machining process.
2. Material is the fundamental guarantee of torsional resistance
ST threading taps are manufactured from high-quality cobalt-containing M35 high-speed steel precisely to meet high-strength requirements. M35 high-speed steel incorporates approximately 5% cobalt from conventional M2 high-speed steel, significantly improving the material's red hardness, wear resistance, and compressive strength. Cobalt promotes uniform carbide distribution and enhances the steel's secondary hardening, enabling the tap to maintain high hardness and toughness even in high-temperature cutting environments. This excellent combination of properties translates directly into greater torsional resistance—even when tapping difficult-to-machine materials such as stainless steel and alloy steel, the tap can withstand high torque without breaking, ensuring complete thread formation.
In addition to the material, the geometry of the tap also plays a decisive role in torsional strength. Machine taps typically feature a larger core diameter to increase overall rigidity. Appropriate flute design ensures smooth chip evacuation while avoiding the weakening of strength caused by thin flute walls. For example, spiral flute taps effectively guide chips upward when tapping blind holes, reducing torque buildup caused by poor chip evacuation. Spiral-point flute taps are suitable for through holes, preventing chips from accumulating at the bottom of the hole and causing tool stagnation. Furthermore, the length and angle of the cutting cone are precisely calculated to ensure smooth entry and avoid excessive transient impact loads.
4. Coating Technology Further Extends Tool Life
Beyond the M35 base material, machine taps can also be treated with surface coatings such as TiN, TiCN, or AlTiN. These hard coatings not only significantly improve wear resistance and reduce frictional heat, but also enhance surface fatigue resistance to a certain extent, indirectly improving torsional resistance. Coated taps exhibit longer service life and greater stability in high-speed tapping, making them particularly suitable for high-volume, continuous production scenarios.
In automated tapping systems, machine ST threading taps are no longer simply cutting tools; they become "high-risk nodes" in the entire production chain. Their torsional strength is directly related to machining yield, equipment safety, and production costs. Machine taps made of M35 cobalt-containing high-speed steel, with their excellent material properties and scientific structural design, can operate stably under the demanding conditions of high speeds and high feeds, effectively resisting sudden torque shocks and minimizing the risk of tap breakage. For modern factories striving for efficient, stable, and unmanned production, choosing machine taps with high torsional strength is not only an investment in tooling but also a safeguard for the safety of the entire manufacturing system.
