Eagle Cutting Tool HT-448-B-I 4-48 Hss Hand Bottom Tap

Product Description

The EAGLE CUTTING TOOL HT-448-B-I is a 4-48 UNF high-speed steel (HSS) hand bottom tap designed for cutting internal threads to the bottom of blind holes. The bottom tap geometry features minimal chamfer on the leading threads, allowing full thread engagement close to the base of a drilled hole. This tap is intended for hand tapping operations and is well suited for precision threading work in metalworking and light fabrication environments. It is installed and used by machinists, maintenance technicians, and skilled tradespeople working with small-diameter fastener applications.

This tap is suited for threading blind holes in ferrous and non-ferrous metals where full thread depth at the bottom of the hole is required. The 4-48 designation indicates a No. 4 screw size with 48 threads per inch, a fine-pitch unified thread commonly found in precision instruments, electronics enclosures, and small mechanical assemblies. It performs well in manual tapping setups using a standard tap wrench or T-handle.

Key Features

• Bottom tap style for threading to the base of blind holes with minimal runout
• 4-48 UNF thread form for fine-pitch small-diameter applications
• High-speed steel (HSS) construction for durability across a range of metals
• Designed for hand tapping operations with standard tap wrenches
• Lightweight at 0.31 pounds for easy handling

Compatibility

Designed as a standard 4-48 UNF hand bottom tap suitable for use wherever a No. 4-48 fine-thread tap is required in manual threading applications.

Installation Notes

Hand tapping should be performed by a qualified machinist or experienced technician using an appropriate tap wrench sized for small taps. Ensure the workpiece is securely clamped before beginning the tapping operation. Apply cutting fluid or tapping oil to reduce friction and extend tap life. Back off the tap periodically to break chips and prevent tap breakage, especially in blind hole applications.

Technical Specifications

• Thread Size: 4-48 UNF
• Tap Type: Hand Bottom Tap
• Material: High-Speed Steel (HSS)
• Weight: 0.31 pounds

Standard Information

• Brand: EAGLE CUTTING TOOL
• Manufacturer Part Number: HT-448-B-I