Lathe machine introduction

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STUDY OF LATHE

Aim

To study about the lathe.

Introduction

                       Lathe is called the father of machine tools. The main function of lathe is to remove metals from work piece to give a required shape and size. In the lathe the work piece is held in a chuck. The tool is moved at an angle 90_ to the axis. Various operations such as straight turning, taper turning, and chamfering, facing, knurling, grooving, thread cutting, taper turning are carried out. When the operations above set are done automatically, then the lathe is called automatic lathe.

Working principle of lathe

                      In a lathe, the workpiece is held in chuck and rotates about its axis by means of power. A single point cutting tool is mounted in tool post. When the chuck rotated the work piece also rotated. The tool moves parallel to the axis of rotation of work piece to produce a cylindrical surface, where as the tool moves perpendicular to the work piece to produce a flat surface. The tool moves at an angle to the axis of work piece to produce a turn surface. The material is removed in the form of chip from the work piece by giving proper feed and depth of cut. So, the required size and shape of the work is obtained.

Main parts of lathe

                      The lathe consists of various parts. Their parts and function are discussed below.

Bed

                       Bed is the base of the lathe. The headstock is mounted on the left end; the carriage is in the middle and the tailstock at the right end of bed. The bed is made up of cast iron, alloyed with nickel, chromium. The bed is made up of cast iron to observe shock and vibration created during machining. The guide ways of the bed may be flatter inverted ‘V’ shape.

Headstock

                        It is mounted on the left end of the bed. It carries a hollow spindle. The live center can be attached in the spindle. The spindle nose is threaded. In chuck faceplates can be attached to the spindle. The headstock may be back threaded type. The headstock has two types of driving mechanism

• Back geared mechanism

• Belt driven mechanism

Tailstock

                        It is located on the bed at the right end. It is used for supports right end of work and also for holding drills, reamer tools for drilling, reaming and such other operations. The tailstock can be moved along the bed and clamped at any position, to support the different length work.

Carriage

                          Carriage is used for giving various feed to the tool by hand or by power. The carriage is attached with the saddle.

Saddle

                          It is a H shaped casting fitted on the bed and moves along the guide ways. It carries the cross slide, Compound rest and a tool post.

i) Cross slide

                            It is attached to the upper side of saddle and carries compound slide and tool post. The cross slide can be moved cross wise by hand or power. The micrometer dial is mounted on the cross slide hand wheel, with an accuracy of 0.05mm.

ii) Compound Rest

                              It is attached over the cross slide. It is used during the taper turning opening operations to set the tool for angular cuts. Here the micrometer dial is mounted to show the depth of cut.

iii) Tool post

                              The tool is clamped over the tool post. It is fixed over the compound rest. There are four types of tool post

                               a. Single screw tool post

                               b. Open side tool post

                               c. Four bolt tool post

                               d. Four way tool post

Apron

                              Apron is attached to the saddle and hangs in front of the bed. It has gears, levers, clutches for moving the carriage automatically. A split nut is attached for engaging and disengaging the carriage from the lead screw. It is used in thread cutting work.

Lead Screw

                               It is a longer screw with standard ACME square threads and used for transmitting power for automatic feed for thread cutting operation.

Feed rod

                               The feed rod is the long shaft used for the movement of carriage along the axis of bed. It is used for operations like facing, turning and boring.

Result

Thus we understand more about the lathe machine parts and it's uses and Lathe operations.