The JB Weld is a good idea. I guess for the lathe I could attach a drill chuck to round stock (in turn attached to the engine with JB Weld) and attach the mandrel to the chuck as needed. I was planning on using a bearing mount for the other end of the lathe.
Thanks for the thoughts and agreed on the grip/cork observation. That is the best outcome of custom finishing, the one grip I turned so far fits like a glove and its my favorite rod simply because of that, plus the cork is like velvet - such a difference with high quality cork.