I have just (as of yesterday) finished my first attempt at a gripper, and have been playing with it for a good few hours.
I have just done a video for you guys so you can grasp the concept (hehe) of how the grippers work.
I went for a design that was a fixed thumb and movable grasp. I decided that I wanted to introduce tolerance into the design by having the fixed thumb plate, it would flex but also offer good grip so that the servo can rotate to its end stop without great stress, yet also offer a good fixed surface to grip against.
**** THIS IS THE FIRST EVER EMBEDDED YT CLIP ON THIS BOARD (SO THERE