If you want to find out whether it is necessary or not then you do not have to go the whole way and weld it up. You could just put a solid disc of steel in the gap normally used to allow for spring compression and then make sure it is well bolted down. My own feeling is that there are some misunderstandings about the movement of the ESA under load. These were typified by Oexings advocacy of the superiority of the BMW design. I went to the trouble of showing a chart on here of the way in which the force exerted by linear rated springs would vary with the rotation of that design. I can't reproduce it from here but the result was that the mechanical design induced a non linear, rapidly increasing force as he components rotated against each other. The Vincent design does not do that. Instead the force exerted increases linearly with rotation. I also pointed out that when Dick Sherwin fitted one of the Australian produced ESAs to his Black Knight and sidecar he found, after a few thousand miles, that only the very bottom of the ESA cams had been used. Removing four of the springs cured that and allowed the cams to move further up their ramps. The problem, it seems to me, is not the mechanical design of the ESA cams but the strength of the springs used. There is absolutely no problem in getting springs made. Even I, with a completely non engineering background, have had four different strengths of spring made for the JE steering stem mod, for Series A seats and for a variety of different drum brake shoes. I believe that Stu Spalding has already had stronger springs made for the ESA and clutch shoe centralisation. If stronger springs are required then there should be no problem getting them made,