I've also run U.S. power tools from the 110V site transformers as well, and never experienced any problems.
The "universal" motor is the one you will find in just about all hand-held power tools, and the frequency difference on these is of no great significance. In fact some universal motors are designed to be run on DC as well as AC (many older domestic vacuum cleaners had such a motor, for example).
These universal motors are all of the asynchronous type, meaning that the rotor speed is not locked to the supply frequency. Synchronous motors are found in such items as electric clocks (mechanical type), small fans, and older style record players and tape recorders.
I'm confused about the tool being live with 55 volts with the switch even in the off position. I didn't get a shock, burn, or tingling sensation yet
Don't worry, you won't be zapped!
The 120V you get from a wall outlet in the United States has a "hot" line and a neutral, just as a 240V British socket provides a live and a neutral. In both cases, the neutral is grounded (earthed) at source, so there is no voltage between it and the earth. The live/hot line is then at 120 or 240V with respect to earth.
The British 110V site transformer has a transformer winding with the center-tap earthed. That means that the two supply lines are both "hot" -- There is 110V between the two wires, but only 55V between either wire and earth. The idea is that the reduced voltage to earth improves safety (and we've had debates about that in the past!).
In practice, as far as your portable power tools are concerned, that's of no consequence so long as you don't go poking around inside them with the power connected.