I can see your apprehension on the freezer part RSD. We use the dissimilar temp routine on a lot of aircraft assemblies, even on turbine engines, and will generally use CO2 or liquid nitrogen to negate contamination.
The big problem though for anyone who has never played with doing an assembly using the heat one part, cool the other part, and shove them together. You need to realize that you have a very very small window of time to assemble those parts and if you get it wrong, well, in the words of my dear granny, you are fugged....
If you are enjoying doing your own wrenching, or do it to save the dough, a small press from harbor freight will not set you back all that much. Just make sure you go slow, lube it, and start it straight.
Ok I will go back to enjoying that beer, Mr. Side-Down, continue on.