You have a manual? If I remember correctly you tighten the nut until there is a 4-5 mmm gap from the bottom of the purple plate to the bottom edge of the knurled adjustment knob. I set mine to 6mm once and quicly stripped the gears out on my Hitec 5645 servo. The JR9000T and the Hitec ti. gear servos can handle being that tight though. If you just bash set it to 4mm's, that is the factory setting.