The carriage of a lathe

The carriage of a lathe has several parts that serve to support, move and control the cutting tool. It consists of the following parts: 1.Saddle 2.Cross-slide 3.Compound slide or compound rest 4.Tool post and 5.Apron Saddle The saddle is an H-shaped casting that fits over the bed and slides along the ways. It carries the cross slide and tool post. Some means are generally provided for locking the saddle to prevent any movement when surfacing operations are carried out. The cross slide The cross-slide comprises a casting machined on the under aside for attachment to the saddle and carries locations on the upper face the tool post or compound rest. The crosspiece of the saddle is mechanized with a dovetail way, at right angles to the center axis of the lathe, which serves to guide the cross-slide itself. The compound rest The compound rest or compound slide is a mounted on the top of the cross-slide and has a circular base graduated in degrees. It is used for obtaining angular cuts and short taper as well as convenient positioning of the tool to work. By loosening two setscrews, which fit in a v- grove around the compound-rest base, the rest slide may be swiveled to any angle within circle. There is no power feed to the compound rest and it is hand operated. The compound rest handle is also equipped with a micrometer dial to assist in determining the depth of the cut. After necessary setting the compound slide is locked solid with its base. The tool post This is located on the top of the compound rest to hold the tool enable it to be adjusted to a convenient working position. Following are the common tool post: 1.Single screw tool post 2.Four bolt tool post 3.Open side tool post 4.Four way tool post The apron The apron is fastened to the saddle and hangs over the front of the bed. It contains gears, clutches, and levers for operating the carriage by hand and power feeds. The e apron also contains function clutches for automatic feeds. In addition, there is a split nut which engages, when required with the lead screw, when cutting either internal or external threads. The lay out of the apron includes an inter locking device which prevents the simultaneous engagement of the feed shaft and the lead screw. The apron handle wheel can turned to move the carriage back and forth longitudinally by hand. The complementary motion to this is obtained by the cross- feed handle, which moves the cross- slide back and forth across the saddle. The handle wheel is connected via a pinion meshing with a rack fitted to the lathe bed Usually a chasing dial or thread cutting dial is fitted either to the side or top of the apron and consists of a graduated dial. It has entirely independent drive provided by a worm wheel, which is a constant mesh with the lead screw. 

fr. NTTF ( NETTUR TECHNICAL TRAINING FOUNDATION)