decayed capstan in Archive QIC

Howdy; Last night I discovered with no small amount of chagrin that the rubber capstan in the Symbolics' QIC drive had turned to proverbial goo. Fortunately the Genera distribution tape I used to discover this is only superficially damaged, since it's my only copy. That'll teach me. (: Anyway, I hoped to take the capstan out of a newer Archive QIC and just replace the whole assembly, but they are mechanically dissimilar just enough so this won't work. Enough of the original rubber is gone that I have no indication of what the original diameter of the capstan is. The drive is an Archive 5945L-2. What is the significance of this; how similar is it to other, older Archive QIC units, what interface did they use (it and a similar Archive QIC unit in one of my Convergent NGEN machines both use the same, 50-ish conductor IDC edge-connectors), and how likely is it that this is a common drive? I need to find out what the thickness of rubber in the capstan (and/or its full outside diameter) is so I can begin considering how to repair this. Thoughts, comments, musings? Tony, I think this might be just up your alley. (: ok r.