Gathering/Gather to fit "1.5 – 2"
At a setting of 1.5 - 2 the front feed dog (2) covers a longer distance than the rear feed dog (1).

Gathering
- To gather intentionally, increase the differential feed to a value between 1.5 and 2.
Gather to Fit
- To prevent waving increase the differential feed to a value between 1 and 2.