Eagle Cutting Tool HT-172-B-I Hss Hand Bottom Tap 1-72

Product Description

The EAGLE CUTTING TOOL HT-172-B-I is a 1-72 high-speed steel (HSS) hand bottom tap designed for cutting internal threads close to the bottom of a blind hole. The bottom tap geometry features minimal lead threads, allowing the cutting edge to reach near the full depth of a hole where plug or taper taps cannot follow. This tap is sized to the 1-72 thread specification, meaning a 0.073-inch nominal diameter with 72 threads per inch, making it suited for fine-threaded fastener work in precision components. Machinists, toolmakers, and maintenance technicians working with miniature hardware install this tap by hand using a tap wrench.

The HT-172-B-I is used in applications requiring fine-pitch internal threads in small-diameter blind holes. Typical installations include instrument assembly, electronics hardware, optical equipment, and light mechanical assemblies where 1-72 machine screws are the fastener of choice. This is an import-grade tap suited for production runs and general shop use where high-volume throughput makes cost-per-tap a practical consideration over premium domestic tooling.

Key Features

• Bottom tap geometry allows threading to near full depth in blind holes
• High-speed steel (HSS) construction provides hardness and wear resistance across a range of workpiece materials
• 1-72 thread form for fine-pitch miniature fastener applications
• Hand tap design for use with a standard tap wrench
• Import grade offers a practical cost option for general shop and production use

Compatibility

Designed as an OEM-style replacement or standard shop tap for use in any application requiring a 1-72 UNF bottom hand tap.

Installation Notes

This tap is installed by hand using a tap wrench — power tapping with this tool is not recommended. Before tapping, ensure the correct tap drill size for 1-72 threads is used and the workpiece is secured. Apply cutting fluid appropriate to the workpiece material to extend tap life and reduce the risk of breakage. Use a reversing motion periodically to break chips, particularly in deeper blind holes.