Eagle Cutting Tool HT-40000-8-B-I Hss Bottom Tap 4in 8TPI

Product Description

The EAGLE CUTTING TOOL HT-40000-8-B-I is a high-speed steel (HSS) special bottom tap designed for threading to the base of blind holes. Sized at 4 inches diameter with 8 threads per inch (TPI), this tap is built for heavy-duty threading applications where a plug or taper tap cannot reach full thread depth. Bottom taps carry minimal lead threads, allowing them to cut usable threads as close to the bottom of a hole as possible. Machinists, toolmakers, and industrial maintenance technicians rely on this tool when thread runout cannot be tolerated in close-tolerance work.

This tap is suited for use in production machining, fabrication shops, and maintenance environments where large-diameter internal threads are required. The 4 inches-8 TPI thread form is commonly found in heavy industrial machinery, large fastener assemblies, press frames, and structural components. HSS construction provides adequate toughness and wear resistance for threading steel, cast iron, aluminum, and similar materials when proper cutting fluid is applied.

Key Features

• Bottom tap geometry with minimal lead threads for threading to the base of blind holes
• 4 inches diameter, 8 TPI thread form for large-diameter heavy industrial threading
• High-speed steel (HSS) construction for toughness across a range of machinable metals
• Special bottom tap designation for close-tolerance applications where full thread depth is required
• Weighs 2.12 pounds, indicating a full-size industrial tap body

Compatibility

Designed as an OEM-style replacement or direct-use industrial bottom tap for machines and fixtures requiring a 4 inches-8 TPI internal thread profile.

Installation Notes

Bottom taps should be used only after a taper or plug tap has established the thread lead in the hole. Secure the workpiece firmly and use a calibrated tap wrench or machine tapping head to maintain axial alignment throughout the cut. Apply appropriate cutting fluid for the material being tapped to reduce heat buildup and extend tap life. Follow applicable shop safety procedures and ensure the tap is fully backed out and cleared of chips between passes.

Technical Specifications

• Thread Size: 4 inches
• Threads Per Inch (TPI): 8
• Tap Type: Special Bottom Tap
• Material: High-Speed Steel (HSS)
• Weight: 2.12 pounds
• Minimum Order Quantity: 1

Standard Information

• Brand: EAGLE CUTTING TOOL
• Manufacturer Part Number: HT-40000-8-B-I