Seco 10139252 Thread Forming Tap G1/8-28 Hss-e Tn Coated

Product Description

The SECO 10139252 is a thread forming tap designed to produce internal threads without cutting, using cold-forming pressure to displace material rather than remove chips. Sized for the G 1/8-28 thread standard, it features a modified bottoming chamfer that allows threading close to the bottom of a blind hole. The tap is manufactured from High-Speed Steel-E (HSS-E), providing improved toughness and heat resistance over standard HSS. A titanium nitride (TN) coating reduces friction and extends tool life in production environments. This tool is used by machinists and maintenance technicians in precision thread-forming applications on ductile metals.

The SECO 10139252 is suited for residential and light industrial maintenance work wherever G 1/8-28 internal threads are required, including hydraulic fittings, pneumatic components, and fluid system ports common in HVAC, plumbing, and industrial equipment. The modified bottoming chamfer makes it particularly effective when thread depth is limited. It belongs to the SECO Series T33 tap family and is packaged and sold as a single-piece unit.

Key Features

• Thread forming action eliminates chips, reducing the risk of chip contamination in blind holes
• Modified bottoming chamfer allows threading close to the bottom of a blind hole
• HSS-E construction provides enhanced toughness and heat resistance
• TN (titanium nitride) coating reduces friction and improves tool life
• G 1/8-28 thread form compatible with standard British pipe parallel thread fittings
• Series T33 design for consistent dimensional accuracy across production runs

Compatibility

Designed as an OEM-style replacement and general-use thread forming tap for G 1/8-28 threaded ports and fittings in ductile metals. Verify workpiece material suitability for cold-form tapping before use.

Installation Notes

Thread forming taps require a specific tap drill size larger than that used for cut taps — confirm the correct forming drill diameter for G 1/8-28 before drilling the pilot hole. Use a tapping fluid or cutting oil appropriate for the workpiece material to reduce forming torque and protect the coating. Secure the workpiece and use a properly aligned tap wrench or machine spindle to avoid tap breakage. Follow applicable shop safety procedures and deburr the hole entry before tapping.