The GO plug gauges for G BSPP parallel pipe threads are inspection tools designed to verify the functional acceptance of internal parallel threads according to DIN ISO 228 part 1. They are suitable for checking threaded holes on fittings, valve bodies, sleeves, adapters, pneumatic components, hydraulic parts, fluid power elements and mechanical components intended for non-pressure-tight threaded joints. G parallel pipe threads, also known as BSPP, use a 55° Whitworth profile and are widely used in fluid systems, pneumatics, hydraulics, industrial piping and technical connections with parallel gas pipe thread standards.

Unlike complete GO / NO GO gauges, these plug gauges perform the GO function only: they must screw correctly into the internal thread without forcing, confirming that the thread meets the minimum acceptance requirements and that the component can mate with the corresponding male fitting or threaded element. They do not check the upper tolerance limit like a NO GO side, but they are particularly useful for quick functional checks, production inspection, maintenance, incoming inspection and operational verification of threaded components.

G parallel threads according to ISO 228-1 are not tapered and do not normally provide sealing by thread interference. In non-pressure-tight threaded joints, sealing is generally achieved by gaskets, washers, flat seats, O-rings or dedicated sealing systems. For this reason, checking the internal thread is important to ensure correct screw-in movement, dimensional compatibility, assembly continuity and absence of obstructions caused by burrs, deformation, machining residues or dimensional errors.

For reliable checking, the GO plug gauge must be used on clean threads, free from chips, burrs, oxides, dirt, coolant residues or visible deformation. During inspection, correct coaxial alignment with the threaded hole must be maintained and the gauge must screw in without being forced, because misaligned or excessive use may damage both the gauge and the inspected component. These gauges are suitable for quality control, mechanical workshops, CNC departments, fitting manufacturers, industrial maintenance, pneumatics, hydraulics, fluid power and plant engineering where the functional acceptance of internal G BSPP parallel threads must be verified simply, quickly and repeatably.

ACCREDIA certification or a calibration report can be supplied on request; because the item must be sent to the inspection or certification body, this documentation may increase delivery time.