Thread Gauge oJIYAS

G ISO-based JIS

Ojiyas Parallel Pipe Threads (G) specified in JIS are used to connect fluid equipments, plumbing parts, pipes where density resistance is unnecessary in their mechanical connection. Limit gauges for parallel pipe threads (G) are used for inspecting the dimension of such threads.

Notes:

• There is no grade in the plug gauges for female screw threads
• The grade of class A and class B are for ring gauges of male screw threads
• Class A and class B are common for GO sides of gauges (GR) only

PF Conventional JIS

Ojiyas Parallel Pipe Threads (PF) specified in JIS are used to connect fluid equipments, plumbing parts, pipes where density resistance is unnecessary in their mechanical connection. Limit gauges for parallel pipe thread (PF) are used for inspecting the dimension of such the threads.

Notes:

The screw threads have two classes of class A and class B. There are gauges for inspection and production use. However, class A and class B are common for GO sides (plug/ring) of gauges only.

B.

NPT National Pipe Taper

Taper pipe threads （NPT） specified in American standard (ANSI) are used to connect pipes, plumb parts, fluid equipments, etc and are purposed to increase the density resistance of the threaded parts. Ojiyas Gauges for taper pipe threads (NPT) are used for measuring dimension of such the threads.

NPTF National Pipe Taper Fuel and Oil

Taper pipe threads NPTF specified in American standard (ANSI) are used to connect fluid equipments, plumb parts, pipes. The density resistance of the thread parts can be obtained even without using seal compound. Ojiyas Gauges for taper pipe threads （NPTF） are used to check the dimension of such the threads.

C. Ojiyas standard thread gauges consist of thread ring gauge and thread plug gauge that fits perfectly. The elements of the screwed parts are made extremely similar to the basic profile of the screw thread. These gauges are not specified in JIS and differs from limit thread gauges, which are usually used in mass-production line. These gauges are suitable for inspecting small amounts of screws which must be engaged perfectly. The screws to be checked should be fitted perfectly as far as possible to the thread gauges.