5x7 Metal Lathes
A high quality metal lathe can be the most valuable machine tool in a working metal shop. It can also be very dangerous if not operated properly. The act of cutting metal on a lathe is known as turning. The majority of engine powered lathes are equipped with 3 jaw chucks but some are offered with 4 jaw chucks. The most important components of any metal lathe are the chuck, the cross-slide, and the tailstock.
The chuck is fastened directly to the drive system of the lathe and it is able to rotate at a range of speeds which can be as high as 6500 RPM's. The piece of metal to be turned must be clamped before it is turned by the chuck. Chucks are self-centering, but pieces of metal are not always straight, so a level must be used to ensure the fit. An indicator is place don't he top of the tool post so that the dial stem touches the metal piece while the machine is turned off and in a neutral chuck rotation position. The trueness of the piece should be checked within one or two thousandths of one inch. Precision machines like metal lathes are designed to cut to sizes within that range or lower. Once the piece has been trued the chuck is tighten as tight as possible and a chuck key is inserted in the key receptacles on each side of the chuck. Trueness is then checked again and then the chuck key is removed and set aside. The key should never be left in the receptacle except when in use for tightening. If left in, the key could fly off while the lathe is in motion.
The tool post carriage and cross slide are the areas where the cutting tool is located. The cutting tool is designed to safely and effectively cut the tip of the tool when locate directly on the center of the piece clamped in the chuck. If it is too high the base of the piece will drag and deflect the depth of the cut. If it is too low, the tip will gouge too deeply. Beginners should use a lower engine speed of rotation and make shallow cuts. They can then slowly increase the speed until a smooth cut can a be accomplished with out causing it to heat up. The dial handle is locate don the cross-slide and is used to check the depth of the cut.
The tailstock is situated on the opposing side of the lathe from the chuck. It is usually used to drill the center of the piece. A Jacob's chuck can be inserted on the sleeve of the unit and fed into the rotating component using the wheel at the end of the tail stock. It can also be used as a live-center which is a cone shaped piece with a tapered shaft which is fitted into the sleeve. The cone spins on the ball bearing mechanism. It is used to fit the center hole of the piece and hold it firmly in place.