What is the second operation (2nd op)?

The second operation is closed by having the second operation roll flatten out the double seam after the first operation roll is complete.

double seam

second op

The second operation roll (2nd operation) irons out the five layers of metal. The thickness of these layers can be calculated using the formula:

Thickness = 3x EndThickness+ 2x BodyThickness + freespace

Critical Second operation measurements include: