Thread plug gauges for NPT, tapered pipe thread

NPT is the American pipe thread with a 1:16 taper. It seals in the thread itself, because the flanks bed against each other as the joint is tightened. A plug gauge checks an internal thread. The go side must screw in, the no-go side must not — which settles the question in seconds, without a caliper and without arithmetic.

VÖLKEL offers 9 versions, from NPT 1/8 x 27 to NPT 2" x 11.5.