JBO Thread Ring Gauge (GO) - UNC - Right Hand - 3A - 5/16 x 18 FMH FLH FHH S&E A&NF M&D while the left‑hand spiral flute

while the left‑hand spiral flute and right‑hand cutting orientation promote predictable chip flow and a clean bore

or dedicated reaming setups

it’s a reliable choice for workshops requiring intermediate-precision reaming

Its ISO H5 tolerance ensures consistent results across parts

ensuring consistent hole size across uses

JBO Thread Ring Gauge (GO) - UNC - Right Hand - 3A - 5/16 x 18 FMH FLH FHH S&E A&NF M&D while the left‑hand spiral fluteThe JBO Thread Ring Gauge (GO) for 5 16 18 UNC is a precision go gauge designed to quickly verify the outer thread diameter and pitch of fasteners and threaded components. It helps inspectors, machinists, and quality teams confirm parts meet UNC specifications with confidence, speeding up inspections and reducing guesswork on the shop floor. Built from hardened steel, this gauge delivers outstanding durability and wear resistance in demanding