Quote Originally Posted by JCarlton View Post
The a-bar is free to move up the swing arm shaft therefore relying on the pressure of the back spring for the amount of "give" when the contact screw is turned up or down it adds more or less pressure resulting in harder or softer give and respective stroke length.
Ahh now it makes sense , when I first saw it my brain went into coil mode and I thought the contact screw had power going to it and wondered how is the motor gonna keep going when the contact is broken.