IBM 3 User Manual page 31

and that the forms are straight.
7. Close the right tractor door.
8. If necessary, slide the right tractor to the right side of the printer to
remove the slack in the form. If the forms are too tight, slide the right
tractor away from the right side of the printer. Ensure that the tractor
pins are centered in the tractor holes.
9. While holding the right tractor in place, lock the right locking lever.
Chapter 1. Getting Started
21