A screen printing machine including a head and at least one screen frame holding arm pivotally mounted on the head for movement about an axis toward and away from a platen between lowered printing and raised non-printing positions, respectively, is provided which includes primary springs associated with the screen frame holding arm, the primary springs attached at one end to first attachment locations on the arm and at another end to second attachment locations on the head for controlling the movement of the arm. Secondary springs for adjusting the spring rate of the primary springs are also provided, the secondary springs in one embodiment extending between the same first and second attachment locations.