If you have any experience working with lathes, then you will know that from time to time they can break down, whether you have a wood lathe or a metal working lathe. They both suffer form the same kinds of problems, so if you are keen on metal working, and want to work out what the problem is with your lathe without having to take it to a specialist, then you can look at several parts of the machine to work out why your metal working lathe is not, well, working.
If the problem appears to be one of poor cutting quality, or you are finding that a piece of metal will not be cut entirely, and is ending up stuck on the blade itself, then your problem may be a blunt blade. These tools can sometimes become very blunt, so you should do your best to keep them sharpened, either by replacing the blade, or sharpening then using a knife sharpener. Check your blade's keenness by running a piece of wood through the lathe, and checking the cut as it comes out the other side. If there is not a clean mark, then you will need to sharpen the blade.
Lathes are highly complicated pieces of equipment, and they often wiggle, or move, slightly during cutting. You can check this by holding a piece of wood in the chuck jaws, and then marking a line using a sharp tool bit. Cut the wood a little lower down, and then note if the marks are parallel. If the lower mark is at all crooked, or dragging downwards, then you will need to tighten the lathe. The blade may be too loose, so screw this more tightly into position first, and then proceed to tighten the lathe and the chuck.
Motor Not Running
If your lathe is not working, this may be due to a problem with the lathe's motor. There are a number of reasons why lathe motors can stop working, including poor lubrication, or a problem with the drive belt. Add lubrication through the oil holes on the side of the motor, and check the drive belt for wear and tear. These belts are made from rubber, so might well become split or cracked through repeated use. You can replace the belt easily enough, and this should help the motor to work again.
There is nothing more frustrating than trying to use your lathe, only to find that the chuck has become stuck, and is no longer moving up and down to the blade. Your only real option is to remove the chuck, and to do this you will need to stop the spindle. Rather than throwing the whole lathe thing a backwards motion, you should try holding the spindle teeth using a toothed wrench, or a special device which grips the toothed edge of the spindle. This will prevent it from moving while you release the chuck. Once you have freed the stuck part, you can restart the lathe.