Beisler 1220-4 - Manual (Page 55)

Chapter 6: Operation
Page 6-31
Pict. 31 Stroke of the presser foot (2)
Pict. 32 Stroke of the presser foot (3)
When the piston pole of the cylinder (7) is driven out, the lever (5)
should attach to screw (2) and the space between sewing foot and
stitch plate should be 5 mm. Additionally, a distance of est. 0.3 mm
should be between stop (11) and screw (10) in this position.