Oh and I seem to have a part two to this question. The big control knob has a screw hole on the left side toward the back at 10:00 and then a slot that is more to the front That I would envision as an adjustable place where an adjustment screw would go.
On my machine there is no adjustment screw-that's the one that is missing. There IS one of those little stud type pressure screws but i can see it in a hole when I look in the slotted area. I feel like that might be in the wrong spot. Anyone??