Without the inboard washer the screw bottoms out before there is any tension on the lever from the friction plates. It just goes flip-idy flop-idy. I would appear that the post on the clamp is a bit too long. With the outboard compression washer & lever in place, I tried to use my thumb to act as the outer screw and I can't get enough pressure on the lever to generate any amount of friction on the lever that would actually hold it in place. It seems like I need a very thin inner washer to take up a little space between the clamp's plate and the lever.