Dimensions, drill sizes and wrench sizes for 3/8-19 BSPP.
Designation
3/8-19 BSPP
Major (outside) diameter
16.662 mm · 0.656"
Pitch
1.337 mm · 19 TPI
Pitch diameter
15.794 mm · 0.6218"
Minor diameter (external)
15.022 mm · 0.5914"
Minor diameter (internal)
15.215 mm · 0.599"
Recommended tap drill
-
Tightening torque estimate
Pipe threads are made up to a seal against the mating flanks, not tightened to a bolt preload, so no proof load or tightening-torque figure applies.
Put 3/8-19 BSPP on a job sheet
The bolt schedule collects the fasteners for one job onto a single sheet - tap drill, wrench size, grade and tightening torque on every line, taken straight from pages like this one. Free schedules hold 3 lines and are saved in this browser only.
3/8-19 BSPP is a BSPP pipe thread running at 19 threads per inch on a 16.662 mm major diameter. BSPP (G) is a parallel thread sealed by a bonded washer or gasket, not by thread interference - so it has no tapered tap-drill sizing.
All values are generated from the standard thread formulas (ISO 68-1 / ASME B1.1) and published standard tables - not hand-entered. See the full reference.
Frequently asked questions
What drill size do I need to tap 3/8-19 BSPP?
Drill - before tapping 3/8-19 BSPP. BSPP (G) is a parallel thread sealed by a bonded washer or gasket, not by thread interference - so it has no tapered tap-drill sizing.
Is 3/8-19 BSPP a tapered or parallel thread?
3/8-19 BSPP is parallel. BSPP (G) threads do not seal on the thread itself; the joint seals on a bonded washer, gasket or O-ring at the face.
How many threads per inch does 3/8-19 BSPP have?
3/8-19 BSPP runs at 19 threads per inch, a pitch of 1.337 mm, on a major diameter of 16.662 mm.
Is there a torque spec for 3/8-19 BSPP?
No. Pipe threads are made up to a seal against the mating flanks, not tightened to a bolt preload, so no proof load or tightening-torque figure applies.