diameter  | number of  | diameter  | stud bolt length  | |||
pipe size  | outside  | bolt circle  | bolt hole  | bolt holes  | of bolts  | 1/4" raised face  | 
0.50  | 3.75  | 2.62  | 0.625  | 4  | 0.500  | 3.00  | 
0.75  | 4.62  | 3.25  | 0.750  | 4  | 0.625  | 3.50  | 
1.00  | 4.88  | 3.50  | 0.750  | 4  | 0.625  | 3.50  | 
1.25  | 5.25  | 3.88  | 0.750  | 4  | 0.625  | 3.75  | 
1.50  | 6.12  | 4.50  | 0.875  | 4  | 0.750  | 4.25  | 
2.00  | 6.50  | 5.00  | 0.750  | 8  | 0.625  | 4.25  | 
2.50  | 7.50  | 5.88  | 0.875  | 8  | 0.750  | 4.75  | 
3.00  | 8.25  | 6.62  | 0.875  | 8  | 0.750  | 5.00  | 
3.50  | 9.00  | 7.25  | 1.000  | 8  | 0.875  | 5.50  | 
4.00  | 10.75  | 8.50  | 1.000  | 8  | 0.875  | 5.75  | 
5.00  | 13.00  | 10.50  | 1.125  | 8  | 1.000  | 6.50  | 
6.00  | 14.00  | 11.50  | 1.125  | 12  | 1.000  | 6.75  | 
8.00  | 16.50  | 13.75  | 1.250  | 12  | 1.125  | 7.50  | 
10.00  | 20.00  | 17.00  | 1.375  | 16  | 1.250  | 8.50  | 
12.00  | 22.00  | 19.25  | 1.375  | 20  | 1.250  | 8.75  | 
14.00  | 23.75  | 20.75  | 1.500  | 20  | 1.375  | 9.25  | 
16.00  | 27.00  | 23.75  | 1.625  | 20  | 1.500  | 10.00  | 
18.00  | 29.25  | 25.75  | 1.750  | 20  | 1.625  | 10.75  | 
20.00  | 32.00  | 28.50  | 1.750  | 24  | 1.625  | 11.25  | 
24.00  | 37.00  | 33.00  | 2.000  | 24  | 1.875  | 13.00  |