How should bolts on a 8-bolt flange be tightened?

• A. In a cross over pattern
• B. In numerical sequence 1 to 8
• C. All at once to maximum torque
• D. Clockwise around the flange

Answer: (A)

The key idea is to achieve even clamping around the flange to compress the gasket uniformly and avoid distortion. With eight bolts, you do this by tightening in a cross or star-like pattern: pick one bolt, then tighten the bolt opposite it, and continue tightening in a crisscross sequence around the circle. This alternating pattern pulls the flange together evenly, so all bolts see similar loading and the gasket seats evenly.

Always tighten in steps to the specified final torque, not all at once, to prevent local over-tightening, gasket extrusion, or flange bending. Tightening in a single sweep around the circle or in a purely clockwise sequence biases the load to one side and can lead to leaks or damage. A simple sequential order without the cross pattern can also create uneven seating even if it ends at the correct torque.