Hertel K014643AS Straight Flute Tap 7/8-14 Unf Hss

Product Description

The HERTEL K014643AS is a straight flute plug tap designed for cutting 7/8-14 UNF right-hand internal threads in ferrous and non-ferrous materials. Built from high-speed steel (HSS) with a bright uncoated finish, it delivers reliable performance in through-hole and blind-hole applications where chip evacuation is manageable by the operator. The plug chamfer — typically 3 to 5 threads — provides a balance between starting ease and thread engagement. With an overall length of 4.6875 inches and a thread length of 2.21875 inches, this tap suits standard machine tapping setups as well as hand tapping operations. The H11 thread limit indicates a slightly oversize tolerance, with an amount oversize of 0.0050 inches, accommodating plated or coated fasteners in the finished assembly.

This tap is suited for production and maintenance threading operations requiring a 7/8-14 UNF thread form. It applies to general metalworking environments including fabrication shops, maintenance and repair operations, and light manufacturing. The straight flute geometry is best used in shorter-chipping materials such as cast iron, free-machining steel, and brass. It is not recommended for long-chipping or stringy materials where spiral flute taps provide better chip control. Installation is performed by hand tapping or in conjunction with a tapping attachment on a drill press or CNC machine. Coolant-through capability is not included on this tap.

Key Features

• 7/8-14 UNF thread form with right-hand thread direction
• Plug chamfer (3-5 thread lead) for balanced starting and full thread engagement
• High-speed steel construction for general-purpose tapping in a wide range of metals
• H11 thread limit with 0.0050 inches oversize for plated-fastener clearance
• 4 straight flutes suited to short-chipping materials
• Bright uncoated finish — ready to use as supplied, no coating break-in required

Compatibility

Designed as a standard replacement or production tap for any application requiring a 7/8-14 UNF straight flute plug tap in high-speed steel. Compatible with standard tap holders and tapping attachments sized for a 0.6970-inch shank diameter and a 0.5230-inch square drive.

Installation Notes

Tapping operations should be performed by a qualified machinist or maintenance technician familiar with thread cutting practices. Ensure the workpiece is securely clamped and the tap is properly aligned to the drilled pilot hole before applying torque. Use an appropriate cutting fluid for the workpiece material to reduce heat and extend tap life. For machine tapping, use a torque-limiting tapping attachment to prevent tap breakage; for hand tapping, reverse the tap periodically to break chips.