Loose 1st Operation Roll
When the first operation roll is too loose the first operation roll will be too open, which can ultimately lead to the seam not being closed correctly, as well as a myriad of issues including false seam, long/short body hook, long/short cover hook, overlap issues or even wrinkle issues.
This value is one of the most critical to get correctly.
How to correct a loose (open) first operation roll?
The correct tool to set up the first operation roll position is using a Clearance gauge.