I bought a used Grizzly 12x24 lathe a couple years ago. The motor (1 ½ HP) was 110/220, wired for 110V when I bought it. It ran fine in reverse, but not in forward. I pulled the original Chinese power switch out, and when I unwrapped the tape that covered it, several pieces fell off. They and the plastic that was supposed to hold them in place showed definite signs of overheating!
Because a given motor will draw twice the current at 110 volts as at 220, it can put a strain on the switch (and other components) if wired 110. And Chinese switches are sometimes a bit marginal. I replaced the original switch with a Dayton drum switch.