三针法测量螺纹及三针选择

BSP Thread Measuring

Whitworth Form Wire Selection

Designation

Variable units n pitch

t.p.i.Smallest wire dia. 0.54P M 3 wire measurement "Largest wire dia. 0.76P

G Wire diameter "M = O/D - 1.6008 P + 3.1657 G

Dia. For pitch-line contact 0.56368P

E Effective diameter

"O/D Thread OD "Pitch Smallest wire

Largest wire Pitch-line

Thread depth

(t.p.i.)

wire

Thread Crest Diameter Pitch 3 Wire Measurement 'M'

( " )( " )( " )( " )

(O/D) ( " )( t.p.i. )( " )110.04910.06910.0512440.05821/8" BSP 0.383280.3945140.03860.05430.0402630.04571/4" BSP 0.518190.5277190.02840.04000.0296670.03373/8" BSP 0.656190.6992260.02080.02920.0216800.02461/2" BSP 0.825140.838128

0.0193

0.02710.020131

0.0229

5/8" BSP 0.902140.91513/4" BSP 1.04114 1.05417/8" BSP 1.18914 1.20211" BSP 1.30911 1.32571 1/4" BSP 1.6511 1.66671 1/2" BSP 1.88211 1.89872" BSP

2.347

11

2.3637

1/2" BSP thread 1 1/4" BSP thread

3/4" BSP thread 1 1/2" BSP thread

BS EN ISO 228-1: 2003 Table 1 Thread dimensions

1" BSP thread 2" BSP thread

British Pipe Thread ( Whitworth Form) -- Parallel (BSPP/BSPF) -- (G)

Desig-nation of thread

Number of threads in 25.4 mm

Pitch P Height of thread h major d = D pitch d2 = D2

minor d1 =

D1Lower deviation

Upper deviation Lower deviation Class A Lower deviation Class B Upper deviation

Lower deviation

Upper deviation Lower deviation Upper deviation

1/16280.9070.5817.7237.142 6.56100.107-0.107-0.214000.282-0.21401/8280.9070.5819.7289.1478.56600.107-0.107-0.214000.282-0.21401/419 1.3370.85613.15712.30111.44500.125-0.125-0.25000.445-0.2503/819 1.3370.85616.66215.80614.9500.125-0.125-0.25000.445-0.2501/214 1.814 1.16220.95519.79318.63100.142-0.142-0.284000.541-0.28405/814 1.814 1.16222.91121.74920.58700.142-0.142-0.284000.541-0.28403/414 1.814 1.16226.44125.27924.11700.142-0.142-0.284000.541-0.28407/814 1.814 1.16230.20129.03927.87700.142-0.142-0.284000.541-0.2840111 2.309 1.47933.24931.7730.29100.18-0.18-0.36000.64-0.3601 1/811 2.309 1.47937.89736.41834.93900.18-0.18-0.36000.64-0.3601 1/411 2.309 1.47941.9140.43138.95200.18-0.18-0.36000.64-0.3601 1/211 2.309 1.47947.80346.32444.84500.18-0.18-0.36000.64-0.3601 3/411 2.309 1.47953.74652.26750.78800.18-0.18-0.36000.64-0.360211 2.309 1.47959.61458.13556.65600.18-0.18-0.36000.64-0.3602 1/411 2.309 1.47965.7164.23162.75200.217-0.217-0.434000.64-0.43402 1/211 2.309 1.47975.18473.70572.22600.217-0.217-0.434000.64-0.43402 3/411 2.309 1.47981.53480.05578.57600.217-0.217-0.434000.64-0.4340311 2.309 1.47987.88486.40584.92600.217-0.217-0.434000.64-0.43403 1/211 2.309 1.479100.3398.85197.37200.217-0.217-0.434000.64-0.4340411 2.309 1.479113.03111.551110.07200.217-0.217-0.434000.64-0.43404 1/211 2.309 1.479125.73124.251122.77200.217-0.217-0.434000.64-0.4340511 2.309 1.479138.43139.951135.47200.217-0.217-0.434000.64-0.43405 1/211 2.309 1.479151.13149.651148.17200.217-0.217-0.434000.64-0.43406

11

2.309

1.479

163.83

162.351

160.872

0.217

-0.217

-0.434

0.64

-0.434

BS EN ISO 228-1: 2003 data chart above revised and updated 12/20/11

External thread Td2

Internal thread TD1Tolerances on pitch diametera

Tolerance on minor Tolerance on major External thread Td Diameters

Internal thread TD2