Value Collection JY4919080 Straight Flute Tap 1-8 Unc

Product Description

The VALUE COLLECTION JY4919080 is a straight flute tap designed to cut internal left-hand threads in metal workpieces. It is configured for 1-8 UNC threading with a plug chamfer, making it suited for through-hole and moderately deep blind-hole applications where a partial chamfer lead aids thread starting. Built from high-speed steel with a bright, uncoated finish, this tap delivers reliable cutting performance across a range of ferrous and non-ferrous materials. The H4 thread limit supports consistent tolerance control, and the 3B class of fit designates it for standard internal thread engagement. Four straight flutes channel chips during cutting. Overall length is 5.125 inches, and the tap weighs approximately 1.24 pounds.

This tap is intended for use in machine shops, maintenance operations, and production environments where left-hand UNC threading is required. Left-hand taps are specified when fastener assemblies demand reverse-thread engagement to prevent loosening under rotational loads. The 1-8 UNC size is a coarse-thread, large-diameter designation commonly found in heavy fasteners, structural components, and industrial machinery. A licensed machinist or tool-and-die technician typically installs this tap in a tapping head, CNC machine, or rigid tap fixture.

Key Features

• 1-8 UNC left-hand thread form with H4 thread limit for controlled tolerance
• Plug chamfer (3-5 thread lead) suits through-holes and moderate-depth blind holes
• Four straight flutes for chip clearance during cutting
• High-speed steel construction for durability across a range of workpiece materials
• Bright, uncoated finish — no coating interference with close-tolerance cuts
• 3B class of fit for standard internal thread engagement

Compatibility

Designed as an OEM-style replacement or direct-use tap for machine tapping applications requiring 1-8 UNC left-hand internal threads at a 3B class of fit.

Installation Notes

This tap is installed by a qualified machinist using a tapping machine, CNC machining center, or manual tap wrench with a rigid holder. Always secure the workpiece fully before tapping, and confirm spindle direction is set to left-hand rotation before engaging the tap. Apply appropriate cutting fluid for the workpiece material to reduce heat and extend tap life. Inspect the tap for wear or chipping before each use — a worn tap in high-speed steel can snap without warning under load.