Nominal Pipe Size 25/125/150 LB. DRILLING 250/300 LB. DRILLING NAVY DRILLING
COMMON SIZE BOLT HOLE DIAMETER
Drilling Column		    
O.D. B.C. DIA. No. B.H. 1 2 3 4 O.D. B.C. DIA. No. B.H. B.H. DIA. O.D. B.C. DIA. No. B.H. B.H. DIA.
1/4 2-1/2 1-11/16 4 7/16 3-1/4 2-1/8 3 9/16
3/8 2-1/2 1-11/16 4 7/16 3-3/8 2-1/4 3 9/16
1/2 3-1/2 2-3/8 4 5/8 5/8 3-3/4 2-5/8 4 5/8 3-9/16 2-7/16 3 9/16
3/4 3-7/8 2-3/4 4 5/8 5/8 4-5/8 3-1/4 4 3/4 3-13/16 2-11/16 4 9/16
1 4-1/4 3-1/8 4 5/8 5/8 4-7/8 3-1/2 4 3/4 4-1/4 3-1/8 4 9/16
1-1/4 4-5/8 3-1/2 4 5/8 5/8 5-1/4 3-7/8 4 3/4 4-1/2 3-3/8 4 9/16
1-1/2 5 3-7/8 4 5/8 5/8 6-1/8 4-1/2 4 7/8 5-1/16 3-15/16 6 9/16
2 6 4-3/4 4 3/4 3/4 6-1/2 5 8 3/4 5-9/16 4-7/16 6 9/16
2-1/2 7 5-1/2 4 3/4 3/4 7-1/2 5-7/8 8 7/8 6-1/8 5 6 9/16
3 7-1/2 6 4 3/4 3/4 8-1/4 6-5/8 8 7/8 6-5/8 5-1/2 8 9/16
3-1/2 8-1/2 7 8 3/4 3/4 9 7-1/4 8 7/8 7-3/16 6-1/16 8 9/16
4 9 7-1/2 8 3/43/4 3/4 3/410 7-7/8 8 7/8 7-11/16 6-9/16 8 9/16
4-1/2                     8-3/16 7-1/16 10 9/16
5 10 8-1/2 8 7/83/4 7/8 3/411 9-1/4 8 7/8 9-1/16 7-13/16 10 11/16
5-1/2                      9-9/16 8-5/16 10 11/16
6 11 9-1/2 8 7/8 3/4 7/8 3/4 12-1/2 10-5/8 12 7/8 1 0-1/8 8-7/8 12 11/16
6-1/2                       10-5/8 9-3/8 12 11/16
7                       11-5/16 10 12 11/16
7-1/2                       11-7/8 10-9/16 12 11/16
8 13-1/2 11-3/4 8 7/8 3/4 7/8 3/4 15 13 12 1 12-3/8 11-1/16 14 11/16
8-1/2                       12-15/16 11-5/8 14 11/16
9                       13-15/16 12-3/8 14 13/16
9-1/2                       14-1/2 12-15/16 14 13/16
10 16 14-1/4 12 1 3/4 1 3/4 17-1/2 15-1/4 16 1-1/8 15 13-7/16 15 13/16
11                       16-9/16 15 16 13/16
12 19 17 12 1 3/4 1 3/4 20-1/2 17-3/4 16 1-1/4 17-5/8 16-1/16 18 13/16
14 21 18-3/4 12 1-1/8 7/8 1-1/8 7/8 23 20-1/4 20 1-1/4 19-1/8 17-3/8 19 15/16
16 23-1/2 21-1/4 16 1-1/8 7/8 1-1/8 7/8 25-1/2 22-1/2 20 1-3/8 21-3/16 19-7/16 20 15/16
18 25 22-3/4 16 1-1/4 7/8 1-1/4 7/8 28 24-3/4 24 1-3/8 23-1/4 21-1/2 22 15/16
20 27-1/2 25 20 1-1/4 7/8 1-1/4 7/8 30-1/2 27 24 1-3/8 25-13/16 23-13/16 24 1-1/16
22 29-1/2 27-1/4 20     1-3/8 7/8 33 29-1/4 24 1-5/8 27-7/8 25-7/8 26 1-1/16
24 32 29-1/2 20 1-3/8 7/8 1-3/8 7/8 36 32 24 1-5/8 30 28 28 1-1/16
25                       31-1/2 29-1/4 29 1-3/16
26 34-1/4 31-3/4 24     1-3/8 7/8 38-1/4 34-1/2 28 1-3/4 32-9/16 30-6/16 30 1-3/16
28 36-1/2 34 28     1-3/8 7/8 40-3/4 37 28 1-3/4 34-11/16 32-7/16 32 1-3/16
30 38-3/4 36 28 1-3/8 1 1-3/8 1 43 39-1/4 28 2* 36-13/16 34-9/16 35 1-3/16
32 41-3/4 38-1/2 28     1-5/8 1 45-1/4 41-1/2 28 2 39 36-3/4 36 1-3/16
33                       40 37-3/4 36 1-3/16
34 43-3/4 40-1/2 32 1-5/8 1 47-1/2 43-1/2 28 2 41 38-3/4 36 1-3/16
35                   42-7/8 40-3/8 36 1-5/16
36 46 42-3/4 32 1-5/8 1 1-5/8 1 50 46 32 2-1/4* 43-7/8 41-3/8 36 1-5/16
38 48-3/4 45-1/4 32     1-5/8 1 56 43 32 1-5/8 46-1/8 43-5/8 36 1-5/16
40 50-3/4 47-1/4 36 1-5/8 1-1/8 1-5/8 1 48-3/4 45-1/2 32 1-3/4 48-1/8 45-5/8 36 1-5/16
42 53 49-1/2 36 1-5/8 1-1/8 57* 52-3/4* 36* 2-1/4* 50-1/4 47-3/4 38 1-5/16
44 55-1/4 51-3/4 40 1-5/8 1-1/8 53-1/4 49-3/4 32 1-5/8        
46 57-1/4 53-3/4 40 1-5/8 1-1/8 55-3/4 52 28 2 54-1/2 52 40 1-5/16
48 59-1/2 56 44 1-5/8 1-1/8 1-5/8 1-1/8 65* 60-3/4* 40* 2-1/4*
Specifications: 25/125/150 LB. DRILLING
ANSI B16.1-1975 Class 25 – 2
ANSI B15.1-1975 Class 125 – 1
ANSI B16.24-1971 – 1
ANSI B16.5 Class 125/150 – 3		 AWWA C207-78
Tbl 1 & 2, Class D, Tbl 3, Class E – 3
AWW C207-78 Tbl 1 & 2, Class B – 4
MSS SP-44 1975 Class 150 – 1
SS SP-51 1965 MSS 150# – 1		 Specifications: 250/300 LB. DRILLING
ANSI B16.1-1975 Class 250
ANSI B16.24-1971 300 lb.
ANSI B16.5-1973 Class 300
MSS SP-44-1975 Class 300		 Specifications: NAVY DRILLING
MIL-F-20042C – 50 lb.
MIL-F-20042C – 150 lb.
BU Ships Drawing B.176
PN Flange Specifications
Nominal PN6 PN10 PN16 PN25 PN40
O.D. B.C. DIA. No. B.H. B.H. DIA. O.D. B.C. DIA. No. B.H. B.H. DIA. O.D. B.C. DIA. No. B.H. B.H. DIA. O.D. B.C. DIA. No. B.H. B.H. DIA. O.D. B.C. DIA. No. B.H. B.H. DIA.
DN 25 3.94 2.95 4 0.55 4.53 3.35 4 0.55 4.53 3.35 4 0.55 4.53 3.35 4 0.55 4.53 3.35 4 0.55
DN 32 4.72 3.54 4 0.55 5.51 3.94 4 0.71 5.51 3.94 4 0.71 5.51 3.94 4 0.71 5.51 3.94 4 0.71
DN 40 5.12 3.94 4 0.55 5.91 4.33 4 0.71 5.91 4.33 4 0.71 5.91 4.33 4 0.71 5.91 4.33 4 0.71
DN 50 5.51 4.33 4 0.55 6.50 4.92 4 0.71 6.50 4.92 4 0.71 6.50 4.92 4 0.71 6.50 4.92 4 0.71
DN 65 6.30 5.12 4 0.55 7.28 5.71 4 0.71 7.28 5.71 4 0.71 7.28 5.71 8 0.71 7.28 5.71 8 0.71
DN 80 7.48 5.91 4 0.71 7.87 6.30 8 0.71 7.87 6.30 8 0.71 7.87 6.30 8 0.71 7.87 6.30 8 0.71
DN 100 8.27 6.69 4 0.71 8.66 7.09 8 0.71 8.66 7.09 8 0.71 9.25 7.48 8 0.87 9.25 7.48 8 0.87
DN 125 9.45 9.45 8 0.71 9.84 9.84 8 0.71 9.84 9.84 8 0.71 10.63 10.63 8 1.02 10.63 10.63 8 1.02
DN 150 10.43 8.86 8 0.71 11.22 9.45 8 0.87 11.22 9.45 8 0.87 11.81 9.84 8 1.02 11.81 9.84 8 1.02
DN 175 ---- ---- ---- ---- 12.40 10.63 8 0.87 12.40 10.63 8 0.87 12.99 11.02 12 1.02 13.78 11.61 12 1.18
DN 200 12.60 11.20 8 0.71 13.39 11.61 8 0.87 13.39 11.61 12 0.87 14.17 12.20 12 1.02 14.76 12.60 12 1.18
DN 250 14.76 13.19 12 0.71 15.55 13.78 12 0.87 15.94 13.98 12 1.02 16.73 14.57 12 1.18 17.72 15.16 12 1.30
DN 300 17.32 15.55 12 0.87 17.52 15.75 12 0.87 18.11 16.14 12 1.02 19.09 16.93 16 1.18 20.28 17.72 16 1.30
DN 350 19.29 17.52 12 0.87 19.88 18.11 16 0.87 20.47 18.50 16 1.02 21.85 19.29 16 1.30 22.83 20.08 16 1.42
DN 400 21.26 19.49 16 0.87 22.24 20.28 161.02 22.83 20.67 16 1.18 24.41 21.65 16 1.42 25.98 23.03 16 1.54
DN 500 25.39 23.62 20 0.87 26.38 24.41 20 1.02 28.15 25.59 20 1.30 28.74 25.98 20 1.42 29.72 26.38 20 1.65
DN 600 29.72 27.76 20 0.94 30.71 28.54 20 1.06 33.07 30.31 20 1.30 33.27 30.31 20 1.42 ---- ---- ---- ----

Precision Hose and Expansion Joints can also furnish standards: API Standard 605, British Standard 10:1962, DIN 2633 and ISO 2084 + 2536, and others standards on request.