The composition of the cutting part of the lathe L turning tool is usually explained by taking an ordinary cylindrical turning tool as an example. The cutting part of the turning tool is generally composed of three sides, two edges and one tip.
(l) The three sides are the front, the main back and the secondary back.
1) Front. The surface on which chips flow on a lathe tool.
2) The main back. The surface of the tool on the lathe opposite the transition surface on the workpiece.
3) Vice rear. The surface of the tool on the lathe opposite the machined surface on the workpiece.
(2) The two edges are the main cutting edge and the secondary cutting edge.
1) Main cutting edge. The intersection line between the front of the lathe and the main back is also called the main cutting edge. It does the main cutting work.
2) Secondary cutting edge. The intersection of the front and the back of the vice, the fork is called the secondary blade. It cooperates with the main cutting edge to complete the cutting work and forms the machined surface of the workpiece.
(3) - The tip is the tip of the knife. The tool nose is the intersection of the major and minor cutting edges. In lathes, it is usually the selected point of each reference plane for measuring the angle of the tool.
Due to the many uses and types of turning tools, their structures also have different changes. Lathes, such as cut-off knives and trough turning knives, have two secondary backs, two secondary cutting edges and two tool tips; trapezoidal screw winches have two main backs and two tool tips; inner hole turning tools often grind out two. A relief angle to avoid the back collision with the hole wall, while maintaining the normal cutting relief angle, and the main cutting edge of the forming knife is non-linear and other changes.
(4) The function changes of the cutting edge of the lathe According to the needs of the cutting function, the cutting edge often has some changes.