Bolt holes line up before lifting duct not checked

Check corner-hole alignment before the duct is committed in the air. Close holes can be aligned with drift pins after both sections are supported and level; badly offset holes mean the joint or run needs repositioning.

Stop if

• Ask when connector type, gasket, cleat/bolt schedule, pressure class, or manufacturer detail is unclear.

Watch out

• Do not slot holes or use drift pins, bolts, corners, or clamps to drag a twisted or mismatched joint together.

Check

• Compare connector size, duct orientation, and corner-hole position on the ground when possible.
• Set gasket on one flange face and bring the joining duct in supported and level.
• Put corners on the joining duct.
• Use drift pins only to align holes that are already close, and protected C-clamps/locking clamps to hold flange faces while hardware starts.
• Reposition or replace the piece if alignment requires force.

Steps

• Compare connector size, duct orientation, and corner-hole position on the ground when possible.
• Set gasket on one flange face and bring the joining duct in supported and level.
• Put corners on the joining duct.
• Use drift pins only to align holes that are already close, and protected C-clamps/locking clamps to hold flange faces while hardware starts.
• Reposition or replace the piece if alignment requires force.

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