"It is necessary to regulate the presser foot when sewing heavy or thin material. Pressure is increased by pushing down the bar (button) to sew heavier material. To decrease pressure, push down the knurled part and the bar (Button) will be lifted. Then get the proper pressure by pushing down the bar again to the adequate pressure"
This from the manula i got with mine. Her name is Scout after the Jeep Scout DH used to have, same blue/teal color!
Ginger in CA