Hertel K008667AS25 Straight Flute Tap 1-1/4-12 Unf Hss Tin

Product Description

The HERTEL K008667AS25 is a straight-flute hand and machine tap designed to cut 1-1/4-12 UNF internal threads in a single pass. Built from high speed steel with a titanium nitride (TiN) coating, it delivers extended tool life in ferrous and non-ferrous materials. The plug chamfer — typically 3 to 5 threads of lead — makes it suitable for through-hole tapping where the tap can pass fully through the workpiece. With 6 flutes and an H4 thread limit, the tap holds tight tolerance for a Class 3B fit, appropriate for precision fastener assemblies. Overall length is 5.75 inches with a 2.5625-inch thread length.

This tap is used in machine shops, maintenance and repair operations, and production environments where large-diameter fine-pitch UNF threads are required. The 1-1/4-12 UNF designation is common in hydraulic fittings, tooling fixtures, and mechanical assemblies that demand a fine thread for vibration resistance or precise clamping force. The straight-flute geometry is best suited for through-hole applications in materials that produce broken or powdered chips. Installation is typically performed on a drill press, CNC machining center, or tapping arm at controlled feed and speed.

Key Features

• 1-1/4-12 UNF thread form with Class 3B fit for precision thread engagement
• H4 thread limit for consistent tolerance control in production runs
• 6 straight flutes provide rigidity and chip clearance in through-hole applications
• Plug chamfer (3-5 thread lead) allows full thread engagement in through-holes
• High speed steel construction resists wear across a broad range of workpiece materials
• TiN coating reduces friction and extends tool life compared to uncoated HSS

Compatibility

Designed as a standard replacement or production tap for any application requiring a 1-1/4-12 UNF Class 3B internal thread in through-hole configurations.

Installation Notes

This tap should be installed and operated by a qualified machinist familiar with tapping feeds, speeds, and cutting fluid requirements for the workpiece material. Always secure the workpiece and use appropriate tapping fluid or cutting oil to prevent galling and extend tap life. Ensure the spindle is properly aligned to the hole axis before engaging the tap. Do not force the tap if resistance increases unexpectedly — back off to clear chips before continuing.