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Date Published:Jun. 18. 2015

Taper Pipe Threads

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Taper Pipe Threads

Basic profile, formula and basic dimensions of taper pipe threads

Basic profile applicable to taper male screws and taper female screws

en_13_technical-13-taper-pipe-threads-1

Fitting of taper male screw with taper female screw or parallel female screw

en_13_technical-13-taper-pipe-threads-2

Unit : mm

＊1
Nominal
Diameter of
Thread		 Screw Thread Gauge diameter Gauge diameter position
Number of
screw
threads
(per 25.4㎜)
n		 Pitch
P
(Reference)		 Height of
screw
thread
h 		 Radius
r or r' 		Male Screw Male Screw Female Screw
Outside
diameter
d		 Effective
diameter
d2		 Root
diameter
d1		 From pipe end Pipe edge
Reference
length
a		 Tolerance in
axial line
direction
b 		Tolerance in
axial line
direction
c
Female Screw 
Root
diameter
D		 Effective
diameter
D2		 Inside
diameter
D1
R 1／16
R 1／8
R 1／4		 28
28
19		 0.9071
0.9071
1.3368		 0.581
0.581
0.856		 0.12
0.12
0.18		   7.723
  9.728
13.157		   7.142
  9.147
12.301		   6.561
  8.566
11.445		 3.97
3.97
6.01		 ±0.91
±0.91
±1.34		 ±1.13
±1.13
±1.67
R 3／8
R 1／2
R 3／4		 19
14
14		 1.3368
1.8143
1.8143		 0.856
1.162
1.162		 0.18
0.25
0.25		 16.662
20.955
26.441		 15.806
19.793
25.279		 14.950
18.631
24.117		 6.35
8.16
9.53		 ±1.34
±1.81
±1.81		 ±1.67
±2.27
±2.27
R1
R1 1／4
R1 1／2		 11
11
11		 2.3091
2.3091
2.3091		 1.479
1.479
1.479		 0.32
0.32
0.32		 33.249
41.910
47.803		 31.770
40.431
46.324 		30.291
38.952
44.845		 10.39
12.70
12.70		 ±2.31
±2.31
±2.31		 ±2.89
±2.89
±2.89

＊1　This nominal diameter is for taper male screws. For taper female screws and parallel females screws, the symbol R shall be changed to RC or RP



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