When assembling, thread the standoff onto a M3 30 MM screw and leave the standoff on the end. Using a hammer or other heavy object, hammer into place. standoff will be flush with the top of the knob. Turn the screw until it is about 1 MM from touching the head. Add a drop of super glue and quickly turn the screw until it is flush with the standoff and will turn no more. add the spring and washer and re-insert into the extruder drive.