Value Collection JY4848206 Straight Flute Tap 7/8-20 Unef

Product Description

The VALUE COLLECTION JY4848206 is a straight flute bottoming tap designed to cut internal threads in through-holes and blind holes where the thread must run close to the bottom of the bore. It is manufactured from high-speed steel with a bright, uncoated finish and is sized for the 7/8-20 UNEF thread form. With four flutes and an H4 thread limit, this tap produces a 3B class of fit suitable for standard fastener assemblies. The overall length of 4-11/16 inches provides the shank clearance needed for most tapping chucks and hand tap wrenches. Machinists, tool-and-die makers, and maintenance technicians in general metalworking, automotive, and MRO environments rely on this tap for precision threading operations.

This tap is suited for right-hand internal threading in ferrous and non-ferrous metals where the 7/8-20 UNEF fine-pitch specification is required. The bottoming chamfer — typically 1 to 2 thread leads — allows threads to be cut to within one or two pitches of the bottom of a blind hole, making it the correct choice for any application where a taper or plug tap cannot complete the thread depth. It is commonly used in repair operations, fixture building, and original equipment production runs requiring fine-thread engagement for high-torque or vibration-resistant connections.

Key Features

• 7/8-20 UNEF right-hand thread form for fine-pitch internal threading applications
• Bottoming chamfer allows threading to near the bottom of blind holes
• 4 straight flutes provide chip clearance and cutting stability in through and blind holes
• H4 thread limit ensures consistent 3B class of fit for standard tolerance assemblies
• High-speed steel construction offers good wear resistance across a range of workpiece materials
• Bright, uncoated finish compatible with standard tapping fluids and cutting oils

Compatibility

Designed as a standard replacement or production tap for any application requiring a 7/8-20 UNEF internal thread with a 3B class of fit. Accepts standard straight-shank tapping chucks and tap wrenches sized for the corresponding shank diameter.

Installation Notes

Tapping should be performed by a qualified machinist or tooling technician using a rigid tapping setup or hand tap wrench appropriate for the shank size. Always apply a suitable tapping fluid or cutting oil to the tap and workpiece before and during the threading operation to reduce heat and extend tool life. Ensure the workpiece is securely fixtured and that the correct tap drill diameter for 7/8-20 UNEF has been used prior to tapping. Back the tap out periodically to break chips and clear the flutes, particularly in deeper blind holes.