API 6A Spec Flange Bolt & Ring Chart 6BX 2 1/16" 2 9/16" 3 1/8" 4 1/16" 5 1/8" 7 1/16" 9" 11" 13 5/8" 16 3/4" 21 1/4" 26 3/4" R-23 RX-23 R-26 RX-26 R-31 RX-31 R-37 RX-37 R-41 RX-41 R-45 RX-45 R-49 RX-49 R-53 RX-53 R-57 RX-57 R-65 RX-65 R-73 RX-73 BX-167 API Pressure Rating Flange Size & Bore Ring Gasket 2 1/16" 2 9/16" 3 1/8" 4 1/16" 5 1/8" 7 1/16" 9" 11" 13 5/8" 16 3/4" 18 3/4" 21 1/4" R-24 RX-24 R-27 RX-27 R-35 RX-35 R-39 RX-39 R-44 RX-44 R-46 RX-46 R-50 RX-50 R-54 RX-54 BX-160 BX-162 BX-163 BX-165 2000 lb 5000 lb 6BX API Pressure Rating Ring Gasket 1 13/16" 2 1/16" 2 9/16" 3 1/16" 4 1/16" 5 1/8" 7 1/16" 9" 11" 13 5/8" 18 3/4" BX-151 BX-152 BX-153 BX-154 BX-155 BX-169 BX-156 BX-157 BX-158 BX-159 BX-164 8 8 8 8 8 12 12 16 20 20 24 20 5/8" 3/4" 3/4" 7/8" 1" 1" 1 1/8" 1 1/4" 1 1/4" 1 1/2" 1 5/8" 1 3/4" 4 3/4" 5 1/4" 5 1/2" 6 1/4" 7 1/4" 7 1/2" 8 1/2" 9 1/4" 9 1/2" 10 3/4" 12 1/2" 14 1/4" Number Stud Dimensions of Studs Diameter Length 8 8 8 8 8 12 12 12 16 16 20 24 7/8" 1" 1 1/8" 1 1/4" 1 1/2" 1 3/8" 1 5/8" 1 7/8" 1 5/8" 1 7/8" 2" 2" 6 1/4" 7" 7 3/4" 8 1/2" 10 3/4" 11 1/4" 12 1/2" 14 1/2" 12 3/4" 14 3/4" 17 1/2" 18 3/4" Number Stud Dimensions of Studs Diameter Length 8 8 8 8 8 12 16 16 20 20 20 7/8" 7/8" 1" 1 1/8" 1 3/8" 1 1/2" 1 1/2" 1 7/8" 2" 2 1/4" 3" 5 3/4" 6 1/4" 7" 8" 9 1/2" 11 1/2" 13" 15 3/4" 19 1/2" 21" 26 3/4" Flange Size & Bore Ring Gasket 6BX 2 1/16" 2 9/16" 3 1/8" 4 1/16" 5 1/8" 7 1/16" 9" 11" 13 5/8" 16 3/4" 20 3/4" 26 3/4" R-24 RX-24 R-27 RX-27 R-31 RX-31 R-37 RX-37 R-41 RX-41 R-45 RX-45 R-49 RX-49 R-53 RX-53 R-57 RX-57 R-66 RX-66 R-74 RX-74 BX-168 API Pressure Rating Flange Size & Bore Ring Gasket 6BX 1 13/16" 2 1/16" 2 9/16" 3 1/16" 4 1/16" 5 1/8" 7 1/16" 9" 11" 13 5/8" 16 3/4" 18 3/4" 21 1/4" BX-151 BX-152 BX-153 BX-154 BX-155 BX-169 BX-156 BX-157 BX-158 BX-159 BX-162 BX-164 BX-166 API Pressure Rating Flange Size & Bore Ring Gasket 1 13/16" 2 1/16" 2 9/16" 3 1/16" 4 1/16" 7 1/16" 9" 11" 13 5/8" BX-151 BX-152 BX-153 BX-154 BX-155 BX-156 BX-157 BX-158 BX-159 API Pressure Rating 20000 lb 15000 lb 6BX Flange Size & Bore Number Stud Dimensions of Studs Diameter Length 10000 lb Ring Gasket 3000 lb Flange Size & Bore API Pressure Rating 6BX Number Stud Dimensions of Studs Diameter Length 8 8 8 8 8 12 12 16 20 20 20 24 7/8" 1 7/8" 1 1/8" 1 1/4" 1 1/8" 1 3/8" 1 3/8" 1 3/8" 1 5/8" 2" 2" 6" 7" 6 1/4" 7 1/2" 8 1/4" 8 1/2" 9 1/2" 10" 10 3/4" 12 1/4" 15" 17 1/2" Number Stud Dimensions of Studs Diameter Length 8 8 8 8 8 12 12 16 16 20 24 24 24 3/4" 3/4" 7/8" 1" 1 1/8" 1 1/8" 1 1/2" 1 1/2" 1 3/4" 1 7/8" 1 7/8" 2 1/4" 2 1/2" 5 1/4" 5 1/2" 6 1/4" 7 1/4" 8 1/4" 9" 11 3/4" 13 1/4" 15 1/2" 17 3/4" 17 3/4" 22 1/2" 24 1/2" Number Stud Dimensions of Studs Diameter Length 8 8 8 8 8 16 16 16 20 1" 1 1/8" 1 1/4" 1 3/8" 1 3/4" 2" 2 1/2" 2 3/4" 3 7 3/4" 8 1/2" 9 1/2" 10 1/4" 12 1/4" 17 3/4" 21 3/4" 23 3/4" 30"