Prior to opening the valve on an oxygen cylinder connected to an oxyfuel cutting torch, what should the diaphragm screw be adjusted to?

The diaphragm screw should be adjusted all the way out before opening the valve on an oxygen cylinder connected to an oxyfuel cutting torch. This ensures that the pressure regulator is fully set to allow an appropriate flow of oxygen. By having the screw in this position, it helps to prevent a rapid surge of gas when the cylinder valve is opened, which can lead to unsafe operating conditions.

Setting the diaphragm screw all the way out provides a more manageable control over the oxygen flow, offering greater safety and stability as you begin using the torch. This adjustment allows the regulator to operate within its intended pressure range, ensuring that precision is maintained for effective cutting.

Other settings either partially engage the diaphragm, which may lead to inadequate or overly high gas flow, neither of which is ideal for safe operation. Adjusting it too far in could risk creating excessive pressure, while any partial adjustment doesn’t provide the necessary safety margin needed before initial gas flow.