Bill, Now I am not sure what it is you want to replace. I had assumed you are talking about the rubber (I used the word "rubber" as a catch-all; I did not mean to insist on rubber in the formal sense) donut that provides decoupling of the CW assembly. So what are you referring to when you say, " if the square head of the bolt touches the small collar that holds the assembly in place than you have lost the damper effect"? Obviously you would choose a replacement part that does the job right. Incidentally, these days you can buy O-rings made from just about any variant on rubber that makes sense. Just go on-line to McMaster-Carr or there is another site that specializes in O-rings per se. Neoprene and urethane and etc are probably available. In fact, it would probably be more difficult to buy an O-ring made of conventional "rubber", if you wanted to.
By the way, I have written this elsewhere many times in the face of Chakster’s insistence that the CW has to stick out the back like a full-blown erection, there is some mechanical advantage to having a slight droop such that the center of mass of the CW lies in the plane of the LP. If you notice the design of modern tonearms, like the Triplanar and the Reed and etc, that’s how they do it intentionally.
By the way, I have written this elsewhere many times in the face of Chakster’s insistence that the CW has to stick out the back like a full-blown erection, there is some mechanical advantage to having a slight droop such that the center of mass of the CW lies in the plane of the LP. If you notice the design of modern tonearms, like the Triplanar and the Reed and etc, that’s how they do it intentionally.