Union Butterfield B-17639 1/4-32 NEF GH5 TiN HSS Spiral Point Tap (6 Pcs)

This is a factory-new lot of six (6) Union Butterfield B-17639 spiral point (gun) taps in 1/4-32 NEF (National Extra Fine), tolerance class GH5, with a TiN (Titanium Nitride) gold-colored PVD coating applied over an M1 High-Speed Steel substrate — decoded directly from the label markings "CHG.M1" (chip-free ground, M1 HSS) and confirmed by the distinctive gold finish visible in the photos. The 1/4-32 NEF thread form follows ASME B1.1 and is a fine-pitch unified thread used in applications requiring high thread engagement in thin-wall sections, precision instrument threads, and aerospace or hydraulic fittings where a standard UNF pitch is too coarse. GH5 tolerance (ground H5, +0.0005″ to +0.0010″ oversize on pitch diameter) is appropriate for 2B/3B class-of-fit threaded holes and is well-suited for use in CNC tapping centers and manual tap drivers; TiN coating increases surface hardness, reduces friction, and extends tool life versus uncoated HSS taps. Each tap is individually packaged in a blue plastic clamshell case; SPEC number 10DB17313 is the Union Butterfield catalog/order spec, and LOT #318873 confirms these are from a single production run. Made in USA.

Product Specifications