THREAD CUTTING

Fig. shows the setup of thread cutting on a lathe. Thread of any pitch, shape and size can be cut on a lathe using single point cutting tool. Thread cutting is operation of producing a helical groove on spindle shape such as V, square or power threads on a cylindrical surface. The job is held in between centres or in a chuck and the cutting tool is held on tool post. The cutting tool must travel a distance equal to the pitch (in mm) as the work piece completes a revolution. The definite relative rotary and linear motion between job and cutting tool is achieved by locking or engaging a carriage motion with lead screw and nut mechanism and fixing a gear ratio between head stock spindle and lead screw. To make or cut threads, the cutting tool is brought to the start of job and a small depth of cut is given to cutting tool using cross slide. When manufacturing or rebuilding components to replace worn ones in the field, the machinists, at times, is limited to the type of operations he can perform because the type of machines needed are not available in his particular shop set or van. Therefore, manufacturers have developed various attachments that can be mounted on the lathe to bridge this gap. These attachments, when mounted on the basic engine lathe, will allow the machinists to perform milling, grinding, drilling, and slotting operations. During this task, we will discuss the uses, repair, and adjustments on some of the lathe attachments.When manufacturing or rebuilding components to replace worn ones in the field, the machinists, at times, is limited to the type of operations he can perform because the type of machines needed are not available in his particular shop set or van. Therefore, manufacturers have developed various attachments that can be mounted on the lathe to bridge this gap. These attachments, when mounted on the basic engine lathe, will allow the machinists to perform milling, grinding, drilling, and slotting operations. During this task, we will discuss the uses, repair, and adjustments on some of the lathe attachments.

Source A Textbook of Basic Manufacturing Processes and Workshop Technology by Rajender Singh.