Hertel K010374AS85 Thread Forming Tap 1/4-28 Unf Bottoming Ticn

Product Description

The HERTEL K010374AS85 is a thread forming tap designed for right-hand blind hole threading in 1/4-28 UNF applications. Unlike cutting taps, thread forming taps displace material rather than cut it, producing stronger threads with no chips to clear. This tap is manufactured from high-speed steel and carries a TiCN (Titanium Carbonitride) coating for improved wear resistance and reduced friction during forming. It meets a 2B class of fit with an H4 thread limit, making it suitable for close-tolerance fastener applications. Machinists and tool-and-die tradespeople rely on this tap for production and maintenance threading where thread quality and tool longevity are priorities.

This tap is suited for blind hole threading in ferrous and non-ferrous materials where chip-free thread production is required. The bottoming chamfer with 1 to 2 chamfered threads allows threading close to the bottom of a blind hole. It is a practical choice for maintenance, repair, and production environments in industrial and manufacturing settings where 1/4-28 UNF threads are a standard fastener specification.

Key Features

• Thread forming design displaces material for chip-free, stronger threads in blind holes
• TiCN coating improves surface hardness and extends tool life versus uncoated HSS
• Bottoming chamfer (1-2P) allows threading to near the bottom of a blind hole
• H4 thread limit provides consistent 2B class of fit for close-tolerance applications
• Right-hand thread direction compatible with standard tapping equipment and tap handles
• No coolant-through requirement simplifies tooling setup

Compatibility

Designed for use in 1/4-28 UNF blind hole applications requiring a 2B class of fit. Compatible with standard straight-shank tap holders and manual tap handles sized for a 0.255-inch shank diameter.

Installation Notes

Thread forming taps require a specific tap drill size that is larger than that used for cutting taps — always consult a thread forming drill chart for the correct pre-drill diameter before use. Secure the workpiece and ensure the tap is started square to the hole to prevent thread distortion or tap breakage. Use an appropriate tapping fluid for the workpiece material to reduce forming force and extend tool life. Follow all applicable shop safety procedures when operating drilling and tapping equipment.