Page 367 - BOLA Catalogue

TECHNICAL INFORMATION
Determination – Thread Types
G or R (Whitworth) or BSP (British Standard Pipe) Thread Cylindrical threads which are mainly used in countries with imperial system. The size of e. g. R 3/4" does not stand for a diameter. Thus the corresponding size has to be determined according to charts.
Please note for the final determination whether you have a fitting with G- or R-threads: G-threads, male as well as female, are cylindrical whereas you have to distinguish that male R-threads have a conical form and its female counterpart is cylindrical.
Example:
G 3/8" – O. D. = 16,5 mm
Pitch
19 turns at1"=1,34mm
Thread
Type
O. D.
mm
Pitch
mm
G or R
1/8"
9,6
28 turns at 1" = 0,91
G or R
1/4"
13,0
19 turns at 1" = 1,34
G or R
3/8"
16,5
19 turns at 1" = 1,34
G or R
1/2"
20,8
14 turns at 1" = 1,81
G or R
5/8"
22,8
14 turns at 1" = 1,81
G or R
3/4"
26,3
14 turns at 1" = 1,81
M thread (metric ISO-thread) – standard in Europe
Cylindrical inner and outer diameter which is precise in millimetres. The extremely fine taper of this thread allows the best possible force trans- mission. Metric threads are designated by a capital M plus an indication of their nominal outer diameter, for instance M 10. A pitch deviating from the standard is marked with an appendix like for instance M 10 x 0.75.
Example:
M10–O.D.=10mm Pitch
1,50 mm
Thread
Type
O. D.
mm
Pitch
mm
M
5
5
0,80
M
6
6
1,00
M
8
8
1,25
M
10
10
1,50
M
12
12
1,75
M
16
16
2,00
GL Threads
GL threads are round threads, i. e. there are only round and no sharp ends at the flanks of the screw thread. Due to its simple shape and the round ends of the flanks, this thread can be easily formed
on glass pipes. The extremely high pitch and the large flanks give this thread an important carrying power.
Example:
GL 25 – O. D. = 25 mm
Pitch
3,5 mm
Thread
Type
O. D.
mm
Pitch
mm
GL
12
12
2,0
GL
14
14
2,5
GL
18
18
3,0
GL
25
25
3,5
GL
32
32
4,0
GL
45
45
4,0
GLS
80
80
15,0
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