I just bought a 220 VAC 50 Hz bandsaw and dust collector from someone who brought them back from Australia. Can I use my home 220 VAC circuit or will I need some type of converter?
As the others have suggested in the notes, the frequency of the supply has an effect on the induction motors that power the bandsaw and the dust collector.
If you move a motor designed for 50Hz onto 60Hz power, it will turn faster, by roughly 20%. It will also draw more current (possibly a lot more, it depends on the motor as to how much). The speed may exceed design tolerances on parts such as bearings, the impeller in the dust collector, etc. If the current increases over the motor's full load amperage rating, the motor (or possibly other wiring of the device) would fail.
It seems likely to me that you would be able to buy replacement motors of the correct type cheaper than a frequency converter.
According to this world map from Wikipedia's article on Mains Electricity by country, most countries in the world use either 230 VAC/50 Hz or 120 VAC/60 Hz electrical supplies (supplies are often rated for +/- 10% of the nominal voltage, so 220 VAC is effectively the same as 230 VAC).
If you're in one of the 230 VAC/60 Hz countries, you'll probably need a converter. There may be a label on the bandsaw or a specifications page in the user manual saying what the acceptable supply voltage is; from that you could tell if you can actually plug it into the mains directly.