If you're a serious beekeeper at some point you think about buying a honey extractor. I think this is something you shouldn't rush into. It's an expensive item which most beekeepers only use a few times a year. If you only have a few hives it's usually better to rely on borrowing an extractor from your local bee club.
If you haven't already joined one, now is a good time to do so, you'll find it is invaluable for all sorts of reasons. You can manage very well without a honey extractor by harvesting honeycomb, called cut-comb, this is probably the only way to go if you're using a Kenya top bar hive.
But if the time comes when you decide you must have an extractor you'll need to know there are two basic types, the tangential extractor and the radial extractor. A honey extractor is basically a centrifuge, both types are available with a hand crank or a more expensive motorized version. Both have a cage inside the drum, to hold the frames, which is spun round to throw the honey out of the cells by centrifugal force, it runs down the inside of the drum and is drawn off into a container through a faucet or gate at the bottom.
Before the frames containing the honeycomb is extracted, the capping which the bees have constructed to preserve the honey have to be removed from both sides of the frame with a knife. Many people use a special heated knife which helps to make a clean cut and so preserve the structure of the combs so they can be replaced in a hive after extraction, to be refilled be the bees, thus saving them the effort of making more beeswax combs and therefore increasing honey production.
The tangential honey extractor holds only 2, 3 or 4 frames. The uncapped frames are placed in the cage inside the drum, the lid closed and the drum spun, slowly at first, gently building up the speed. Care should be taken not to spin it too fast at this stage to avoid damaging the fragile combs. Once about half the honey has been extracted from the outer side of the combs, the drum is stopped and the frames reversed so the side which is still full of honey is now on the outside. The cage is spun again, slowly at first, this time it can be spun until all the honey is thrown from the outside face of the frame. The cage is stopped again and the frames reversed again and the last of the honey is spun from the 'first' side.
It's easy to see why the more expensive radial extractor is so popular. The difference is that the uncapped frames are placed in the honey extractor cage in a radial fashion, like the spokes of a wheel. The cage is spun, again slowly at first,although the need for care is much less in a radial extractor because the centrifugal force acts along the center rip of the comb in the frame, rather than at right angles to the comb in a tangiest extractor. The honey is thrown out of the cells onto the inside of the drum from both side of the comb at once. It's necessary to spin them faster than a tangential extractor, which is why many of them are motorized.
Huge radial extractors holding as many as over a hundred frames at a time are available for commercial operations, but one holding perhaps 18 or 20 frames will be satisfactory for even the most productive of hobby or side-liner beekeepers. Machines to uncap the frames before they're put in the honey extractor are available, but few small beekeepers can justify the outlay or the space to accommodate these.