NPSC เกจวัดเกลียวท่อตรง (Straight Pipe Thread)

These are parallel internal threads only in pipe couplings, and have the same thread form as the NPT thread. They are used to form pressure tight joints when assembled with NPT external threads, and made up wrench-tight with a sealant.

The threads range in size from 1/8 inch to 4 inch.

Go/No Go parallel plug gauges can be supplied to test the diametral limits of these threads, although the standard states that NPT taper plug gauges should be used to test the internal product thread where the mating external threads are tapered and a pressure tight joint is required.