Seco 10139694 M3 Straight Flute Tap 3 Flute 6H Hss-e

Product Description

The SECO 10139694 is a straight flute machine tap designed for cutting M3 x 0.50mm metric internal threads in blind holes. It is manufactured from High-Speed Steel-E (HSS-E), a cobalt-bearing grade that provides added toughness and heat resistance compared to standard HSS. The TN (titanium nitride-class) coating reduces friction and extends tool life in production threading applications. With a 3-flute straight flute geometry and semi-bottoming chamfer, this tap is suited for threading close to the bottom of a blind hole while maintaining chip control. It is installed and operated by machinists and CNC tooling technicians in machine shop environments.

This tap is intended for blind hole threading in a range of workpiece materials including steel, stainless steel, cast iron, and non-ferrous metals. The semi-bottoming chamfer allows threading closer to the bottom of a blind hole than a standard taper tap, making it a practical choice for tight-tolerance threaded features in machined components. It belongs to the SECO T32 series and is sized for low-torque M3 applications typical in precision part fabrication and light mechanical assembly.

Key Features

• M3 x 0.50mm metric thread form with 6H class of fit for standard tolerance internal threads
• Semi-bottoming chamfer for threading near the bottom of blind holes
• High-Speed Steel-E construction for improved toughness and wear resistance over standard HSS
• TN finish reduces friction and extends service life in production threading
• 3 straight flutes for chip management in through and shallow blind hole applications
• Right-hand thread direction; compatible with standard machine tap holders and tapping heads

Compatibility

Designed as a machine tap for use in CNC machining centers, drill presses, and tapping machines equipped with standard straight shank tap holders sized for a 2.2mm shank diameter. Suitable for M3 blind hole threading in steel, stainless steel, cast iron, and non-ferrous metal workpieces.

Installation Notes

This tap is intended for installation by qualified machinists using appropriate tap holders or floating tap adapters on machine tools. Ensure the spindle is at a full stop before changing tooling. Use cutting fluid appropriate for the workpiece material to maximize tap life and thread quality. Do not exceed the recommended tapping depth of 36mm and verify blind hole depth before operation to avoid tap breakage.