re the sleeving; it would seem to me that the best and easiest way to assemble an item of the dimensions and shape under discussion would be to cold shrink the sleeve and just slide them together. on a cast iron sleeve of 12 [or 11] in dia, ill just bet that liquid nitrogen would give you .035 to .040 of clearance to assemble, plenty of room, they would just fall together, and warm up and be inseparable!! this may seem drastic, but at any given time i have 50 to 100 gals of liquid nitrogen sitting in my shop, so i dont find it a problem at all. JEFF tucson az.