JBO Thread Ring Gauge (NoGo) - UNC - Left Hand - 2A - No. 4 x 40 Face Mill Arbors - Through Coolant Left-hand spiral flute: Left-hand spiral

Left-hand spiral flute: Left-hand spiral aids chip control and smoother cutting during hand reaming

and workshop professionals who need fast pass/fail checks against standard thread sizes

making it suitable for steel

JBO Thread Plug Gauge is a left-hand

finish-ready holes with the Toolex Reamer — a 12

JBO Thread Ring Gauge (NoGo) - UNC - Left Hand - 2A - No. 4 x 40 Face Mill Arbors - Through Coolant Left-hand spiral flute: Left-hand spiralThe JBO Thread Ring Gauge NoGo is a precision inspection tool designed to verify external UNC threads on fasteners, shafts, and machined components. Sized No. 4 x 40 with a left hand 2A thread, this gauge provides a clear, repeatable check during quality control to confirm threads meet the Unified standard. Designed for fast, reliable pass fail checks, the NoGo gauge helps identify non conforming threads early, reducing rework and downtime. Crafted