JBO Thread Ring Gauge (GO) - UNF - Left Hand - 2A - No. 12 x 28 S&E Size and geometry: 4 mm

Size and geometry: 4 mm diameter with a 25 mm flute length and a 70 mm overall length

improve fit during assembly

and a 4 mm shank diameter to fit common small‑shaft CNC tooling setups

helping you achieve clean chamfers with minimal post-processing

Achieve precise hole finishing to ISO H5 tolerance with the Toolex Reamer — a 20

JBO Thread Ring Gauge (GO) - UNF - Left Hand - 2A - No. 12 x 28 S&E Size and geometry: 4 mmThe JBO Thread Ring Gauge (GO) for UNF left hand threads is a focused inspection tool designed to verify external thread diameters with confidence. Sized No. 12 x 28 and built for 2A class left hand UNF threads, it helps quality teams on the shop floor quickly determine if parts meet the required standards. Crafted from hardened steel for lasting performance, this GO gauge delivers reliable measurements even in demanding environments. Its precise