The easiest thing to do would be to just get the step down transformer and plug them in. The transformer linked to even has the right sockets to plug in US style plugs.
No reason why it should "overload something or die after an hour or be really tricky to use in certain
Sometimes there is a switch to change between the two configurations, sometimes it is a little link connection (or two) known as a jumper lead and sometimes it will require re-wiring.
(If they are both identical and have internal transformers, I would personally try to run them in series - but this is not really good advice so don't do that!!!)