NPS 3/8 Pipe Nipple, ASTM A733

The NPS 3/8 pipe nipple (ASTM A733) joins two NPS 3/8 NPT fittings: Schedule 40 pipe 17.145 mm across with a 2.3114 mm wall, threaded 18 threads per inch at both ends. It comes in 17 lengths from 25.4 to 304.8 mm, each as simplified and threaded STEP.

How these parts are made, and what the levels mean: read the method

• Also searched as: NPS 3/8 pipe nipple, NPS 3/8 x 25.4 to NPS 3/8 x 304.8 pipe nipples
• Model id: astm-a733-nps3-8
• Standard: ASTM A733 · NPS 3/8, pitch 1.411 mm, NPT taper pipe thread (ASME B1.20.1), 60 degree profile, 1:16 taper, right hand

Lengths

Length (mm)	Part key	Simplified	Threaded
25.4	astm-a733-nps3-8x25-4	STEP	STEP
38.1	astm-a733-nps3-8x38-1	STEP	STEP
50.8	astm-a733-nps3-8x50-8	STEP	STEP
63.5	astm-a733-nps3-8x63-5	STEP	STEP
76.2	astm-a733-nps3-8x76-2	STEP	STEP
88.9	astm-a733-nps3-8x88-9	STEP	STEP
101.6	astm-a733-nps3-8x101-6	STEP	STEP
114.3	astm-a733-nps3-8x114-3	STEP	STEP
127	astm-a733-nps3-8x127	STEP	STEP
139.7	astm-a733-nps3-8x139-7	STEP	STEP
152.4	astm-a733-nps3-8x152-4	STEP	STEP
177.8	astm-a733-nps3-8x177-8	STEP	STEP
203.2	astm-a733-nps3-8x203-2	STEP	STEP
228.6	astm-a733-nps3-8x228-6	STEP	STEP
254	astm-a733-nps3-8x254	STEP	STEP
279.4	astm-a733-nps3-8x279-4	STEP	STEP
304.8	astm-a733-nps3-8x304-8	STEP	STEP

Dimensions

Symbol	Name	min	nom	max	Modeled	Rule	Level
l_close_in	Close nipple length, inches		1		1	nominal	L1
l_close	Close nipple length		25.4		25.4	nominal	L1
D	Outside diameter		17.145		17.145	nominal	L1
T	Wall thickness		2.3114		2.3114	nominal	L1
D_in	Outside diameter, inches		0.675		0.675	nominal	L1
T_in	Wall thickness, inches		0.091		0.091	nominal	L1
n	Threads per inch		18		18	nominal	L1
P	Pitch		0.05555555		0.05555555	nominal	L1
D	Outside diameter of pipe		0.675		0.675	nominal	L1
E0	Pitch diameter at the small end		0.61201		0.61201	nominal	L1
L1	Hand-tight engagement length		0.24		0.24	nominal	L1
E1	Pitch diameter at the hand-tight plane		0.62701		0.62701	nominal	L1
L2	Effective thread length		0.4078		0.4078	nominal	L1
E2	Pitch diameter at the end of the effective thread		0.6375		0.6375	nominal	L1
L4	Overall length of external thread		0.6006		0.6006	nominal	L1
h	Height of thread		0.04444		0.04444	nominal	L1
K0	Basic minor diameter at the small end		0.5676		0.5676	nominal	L1
alpha	Flank angle		60		60	nominal	L1
taper	Taper		16		16	nominal	L1

Drawing

As a PDF: CC-ASTMA733-SZ-3-8.pdf.

The NPS 3/8 pipe nipple beside the NPS 1/4 and the NPS 1/2

The NPS 3/8 is number 3 of the 9 ASTM A733 pipe nipples published here, listed from NPS 1/8 to NPS 2.

• Close nipple length, inches (l_close_in): 1 mm on the NPS 3/8 pipe nipple, against 0.875 mm on the NPS 1/4 and 1.125 mm on the NPS 1/2.
• Close nipple length (l_close): 25.4 mm on the NPS 3/8 pipe nipple, against 22.225 mm on the NPS 1/4 and 28.575 mm on the NPS 1/2.
• Outside diameter (D): 17.145 mm on the NPS 3/8 pipe nipple, against 13.716 mm on the NPS 1/4 and 21.336 mm on the NPS 1/2.
• Wall thickness (T): 2.3114 mm on the NPS 3/8 pipe nipple, against 2.2352 mm on the NPS 1/4 and 2.7686 mm on the NPS 1/2.
• Outside diameter, inches (D_in): 0.675 mm on the NPS 3/8 pipe nipple, against 0.54 mm on the NPS 1/4 and 0.84 mm on the NPS 1/2.
• Wall thickness, inches (T_in): 0.091 mm on the NPS 3/8 pipe nipple, against 0.088 mm on the NPS 1/4 and 0.109 mm on the NPS 1/2.
• Threads per inch (n): 18 mm on the NPS 3/8 pipe nipple, against 18 mm on the NPS 1/4 and 14 mm on the NPS 1/2.
• Pitch (P): 0.05555555 mm on the NPS 3/8 pipe nipple, against 0.05555555 mm on the NPS 1/4 and 0.07142857 mm on the NPS 1/2.

Other sizes

• One size smaller: NPS 1/4 Pipe Nipple, ASTM A733, 18 threads per inch, pipe OD 13.716 mm.
• One size larger: NPS 1/2 Pipe Nipple, ASTM A733, 14 threads per inch, pipe OD 21.336 mm.

Documents

• CC-ASTMA733-DS-NPS3-8.pdf: 3/8 datasheet: values with levels, lengths, sources
• CC-ASTMA733-SZ-3-8.pdf: 3/8 drawing: this size's values on the views
• parts.json: the part record of every length (the platform contract)

Sources

anvil-a733-nipples, engineersedge-npt, engineersedge-npt-basic, etb-b36-10, etb-npt, smithcooper-a733-nipples, steeltube-b36-10, ultimatewasher-npt, wikipedia-npt. Full citations: the method page and this size's datasheet.

Found an error? Use the feedback section on this page.