04-25-2015, 07:15 AM
Actually, if shrink fitting two pieces together I would believe a smooth to smooth surface interface gives infinitely more contact area than a knurled surface. That is the whole purpose of a shrink fit, to make two pieces effectively become one. If you have a knurl and want the maximum contact area you would have to have a much greater differential in size to engage the "peaks and valleys" of the knurl, wouldn't you?