Final answer:
Open the acetylene cylinder valve a maximum of 1.5 turns when assembling oxyacetylene welding equipment to ensure safe and proper operation.
Step-by-step explanation:
When assembling oxyacetylene welding equipment, you should open the acetylene cylinder valve a maximum of 1.5 turns. This is the standard recommendation to ensure safe and proper operation of the equipment. Turning the valve too much or too little may result in inadequate or excessive gas flow.