Thread Conversion Specialists
THREAD DIMENSION CHARTS
ISO Metric – 1.5mm Pitch
TPI
Major Dia.
Metric
16.93
15.97mm
M16
16.93
19.97mm
M20
16.93
24.97mm
M25
16.93
31.97mm
M32
16.93
39.97mm
M40
16.93
49.97mm
M50
16.93
62.97mm
M63
16.93
74.97mm
M75
12.70
89.97mm
M90
12.70
99.97mm
M100
NPT
3
⁄8"
1
⁄2"
3
⁄4"
1"
11⁄4"
11⁄2"
2"
21⁄2"
3"
31⁄2"
4"
National Pipe Taper
Major Dia.
17.05mm
21.22mm
26.57mm
33.23mm
41.99mm
48.05mm
60.09mm
72.70mm
88.61mm
101.60mm
114.30mm
PG
PG7
PG9
PG11
PG13.5
PG16
PG21
PG29
PG36
PG42
PG48
TPI
18
14
14
11.5
11.5
11.5
11.5
8
8
8
8
PG DIN 40430
Major Dia.
12.50mm
15.20mm
18.60mm
20.40mm
22.50mm
28.30mm
37.00mm
47.00mm
54.00mm
59.30mm
TPI
20
18
18
18
18
16
16
16
16
16
BSP
3
⁄8"
1
⁄2"
3
⁄4"
1"
11⁄4"
11⁄2"
2"
21⁄2"
3"
THREAD FORM COMPARISON CHART
Metric
M16
M20
M25
M32
M40
M50
M63
M75
M90
M100
NPT
3
⁄8"
1
⁄2"
3
⁄4"
1"
11⁄4"
11⁄2"
2"
21⁄2"
3"
31⁄2"
PG
7, 9, 11
13.5, 16
PG21
PG29
PG36
PG42
PG48
BSP
3
⁄8"
1
⁄2"
3
⁄4"
1"
11⁄4"
11⁄2"
2"
21⁄2"
3"
ET
5
⁄8"
3
⁄4"
1"
11⁄4"
11⁄2"
2"
21⁄2"
3"
Note 1: PF Thread Form (Japan) = BSP Parallel
G Thread Form (Europe) = BSP Parallel
GK Thread Form (Europe) = BSP Taper
Note 2: NPT/BSPT Taper @ 1⁄16 on Major Dia.
BSP BS2779
Major Dia.
16.66mm
20.96mm
26.44mm
33.25mm
41.91mm
47.80mm
59.61mm
75.18mm
87.88mm
TPI
19
14
14
11
11
11
11
11
11
ET
5
⁄8"
3
⁄4"
1"
11⁄4"
11⁄2"
2"
21⁄2"
3"
Imperial Conduit BS31
TPI
Major Dia.
18
15.88mm
16
19.05mm
16
25.40mm
16
31.75mm
14
38.10mm
14
50.80mm
14
63.50mm
14
76.20mm