Can I use a 120 volt 50/60 Hz. tool on a 230 volt 50 Hz. circuit?
It will work with a step down transformer since the output should be 120~10 (120 with 10 +/- possible) with a low quality transformer, which, apparently the tool can handle. In a good transformer it should be 120~2. So the output wont be much different than regular 120 volt output. If it also increases the frequency, that would be much better. And make sure the continuous max rating is 700~20 volts. Otherwise you have a small danger of the lifetime of the transformer decreasing.