JBO Plug Gauge - UNC (STI) Heli Coil Gauge - Right Hand - 2B - No. 4 x 40 - Calibrated (DAkkS Calibration) FMH FLH FHH S&E A&NF M&D Left‑hand spiral flute with right‑hand

Left‑hand spiral flute with right‑hand cutting: Facilitates efficient chip evacuation and controlled material removal for a smooth

Uncoated and built to ISO 529 dimensions

and flexible balancing enables quick changes

Standards & tolerance: DIN 212-B specification with ISO H5 tolerance class for tight bore size control

Rigid tapping precision: Delivers precise

JBO Plug Gauge - UNC (STI) Heli Coil Gauge - Right Hand - 2B - No. 4 x 40 - Calibrated (DAkkS Calibration) FMH FLH FHH S&E A&NF M&D Left‑hand spiral flute with right‑handThe JBO Plug Gauge for UNC (STI) is a precision inspection tool built to verify UNC screw thread inserts (STIs). Part of the Helicoil gauge family, its ideal for engineers, buyers, technicians, and inspectors who need fast, reliable checks on No. 4 x 40 inserts to ensure proper seating and performance in assemblies. Manufactured and assessed to ANSI ASME UNC standards, this plug gauge provides accurate pitch diameter checks for UNC STI inserts. It