Value Collection JY4918090 Straight Flute Tap 7/8-9 Unc

Product Description

The VALUE COLLECTION JY4918090 is a straight flute tap designed to cut left-hand internal threads to the 7/8-9 UNC standard. It features 4 flutes, a plug chamfer for general through-hole and blind-hole threading applications, and is manufactured from high-speed steel with a bright/uncoated finish. The H4 thread limit provides the oversize allowance needed to meet 3B class of fit tolerances. With an overall length of 4.6875 inches and a weight of 0.872 pounds, this tap is suited for machinists, maintenance technicians, and toolroom professionals working with left-hand threaded fastener applications.

This tap is intended for use in manual or machine tapping operations where a left-hand 7/8-9 UNC thread form is required. Left-hand threads are commonly specified in applications where counter-rotation would otherwise loosen a standard right-hand fastener, such as certain spindle assemblies, bicycle components, and rotating shaft hardware. The plug chamfer style makes it versatile for starting threads in both through-holes and deeper blind holes where a taper tap is not required.

Key Features

• Left-hand thread direction for counter-rotation fastening applications
• 7/8-9 UNC thread form with 3B class of fit for standard tolerance internal threads
• H4 thread limit provides proper oversize allowance for 3B fit
• Plug chamfer style suitable for through-holes and moderate-depth blind holes
• 4-flute straight flute geometry for use in most standard tapping operations
• High-speed steel construction with bright/uncoated finish for general-purpose use

Compatibility

Designed as an OEM-style replacement or direct substitute for straight flute taps in 7/8-9 UNC left-hand applications requiring a plug chamfer, H4 thread limit, and 3B class of fit.

Installation Notes

This tap should be installed and operated by a qualified machinist or toolroom professional familiar with tapping feeds, speeds, and cutting fluid requirements for high-speed steel tooling. Always secure the workpiece and use appropriate cutting fluid or tapping compound to extend tool life and achieve clean thread forms. Confirm left-hand thread direction requirements before use, as left-hand taps rotate opposite to standard right-hand taps. Inspect the tap and tap holder for runout before operation to avoid tap breakage.