LATHE OPERATIONS - OD - LESSON 1/TASK 1 and a hollow headstock spindle for feeding bar stock into the machine, or may use a universal scroll chuck. rotating workpiece to generate a cylindrical shape. •Performed on a machine tool called a lathe. •Variations of turning that are performed on a lathe: Facing. the desired shape. ➢ Lathe machine is also known as “the mother/father of the entire tool family”. Applicable in wood turning, metal spinning and operations.
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Turning & Related Operations. • Turning – a machining process in which a single -point tool remove material from the surface of a rotating work piece. (Lathe). Lathe machine is a mechanical device in which the workpiece is rotated against cutting tool for producing cylindrical forms in the metal, wood or. Lathe machine operations are turning operation, facing operation, taper turning operation, knurling operation, grooving operation, thread.
To perform different lathe machine operations on a lathe, the workpiece may be supported and driven by any one of the following methods:. Lathe machine operations done either by holding the workpiece between centres or by a chuck are: Lathe machine operations which are performed by holding the work by a chuck or a faceplate or an angle plate are: It is the most common type of operation in all lathe machine operations. Turning is the operation of removing the excess material from the workpiece to produce a cylindrical surface to the desired length.
The job held between the centre or a chuck and rotating at a required speed. The tool moves in a longitudinal direction to give the feed towards the headstock with proper depth of cut. The surface finish is very good. The workpiece is held on the chuck and it is made to rotate about the axis, and the tool is fed parallel to the lathe axis.
The straight turning produces a cylindrical surface by removing excess metal from the workpiece. It is the process of removal of excess material from the workpiece in a minimum time by applying high rate feed and heavy depth of cut. When a workpiece has different diameters and is to be turned, the surface forming steps from one diameter to the other is called the shoulder, and machining this part of the workpiece is called shoulder turning.
When a cylindrical surface two separate axis of rotation, with the first axis, is offset to the other axis then such a workpiece is machined by the operation called eccentric turning. Here three sets of centre holes are drilled. The amount of taper in the workpiece is usually specified on the basis of the difference in diameter of the taper to its length.
In case of lathe, the taper on a given workpiece is obtained by tuning the job and feeding the tool at an angle to produce a gradual increase or decrease in the diameter of the workpiece. Here the taper length obtain is equal to the width of the form tool. To obtain the required size of the taper the form tool is fed slowly straight into the workpiece by operating the cross slide perpendicular to the lathe axis.
This is the simplest method of taper turning. It is limited to obtain small taper length such as chamfering the side of the workpiece. The method is done at a faster rate. The combined feed is made with the movement of a tool in longitudinal and lateral direction simultaneously while moving the workpiece. The taper, which we are going to obtain, is equal to the resultant to the magnitude of the longitudinal and lateral feeds. Changing the feeds rates in both directions can change the direction and the taper angle.
Here the workpiece rotates and the tool is fed at an angle by swivelled compound rest. The base of the compound rest is graduated in degrees.
Once the compound rest is set to a particular angle then the tool is moved by compound rest and wheel. Here the workpiece on the job is tilted at the required taper angle. The tool is fed parallel to the axis. The tilting of the workpiece or the job to the required taper angle is achieved by the movement of tailstock with the help of tailstock set over the screw.
This method is useful for small tapers. It is an operation of reducing the length of the workpiece by feeding the perpendicular to the lathe axis.
This operation of reducing a flat surface on the end of the workpiece. For this operation, regular turning tool or facing tool may use. The cutting edge of the tool should set to the same height as the centre of the workpiece. It is the operation of getting a bevelled surface at the edge of a cylindrical workpiece. This operation is done in case of bolt ends and shaft ends. Chamfering helps to avoid damage to the sharp edges and protect the operation getting hurt during other operations.
Chamfering on bolt helps to screw the nut easily. It is an operation of obtaining a diamond shape on the workpiece for the gripping purpose. This is done to provide a better gripping surface when operated by hands. It is done using a knurling tool. The tool consists of a set of hardened steel roller, and it is held rigidly on the toolpost.
Knurling is done at the lowest speed available on a lathe. It is done on the handles and also in case of ends of gauges. The feed varies from 1 to 2 mm per revolution. Two or three cut may be necessary to give the full impression. When the threads or helical grooves are formed on the out surface of the workpiece is called external thread cutting. The wood piece is placed in between the headstock and the tailstock of the lathe.
The products produced with the help of the lathe machine are cue sticks, musical instruments, candlestick holders, table legs, baseball bats, gun barrels, camshafts, bowls, crankshafts and much more. There are plenty of lathe that vary in sizes and shapes according to the work to be done. Lathes Operations The general operations done with the lathe are grooving, turning, cutting, sanding and etc.
Each lathe operation has got its own factors that need to be considered before doing the work. The factors should be used properly so that one can avoid from mishandling and mishaps while performing any kind of lathe operation. With every cut desired the speed, depth and feed of the lathe machine is changed for precision. Types of Lathe Operation The working of the lathe machine changes with every operation and cut desired.
There are a lot of operations used for using the lathe machine.
Some of the common lathe operations are: Facing This is usually the first step of any lathe operation on the lathe machine. Chamfering: It removes the burrs and sharp edges, and thus makes the handling safe. Grooving: The term grooving usually applies to a process of forming a narrow cavity of a certain depth, on a cylinder, cone, or a face of the part.
The rough surface produced by knurling is useful for providing proper gripping. Taper Turning: The taper turning is a lathe operation for producing a conical surface by a gradual reduction in the diameter of a cylindrical workpiece.
Thread Cutting: A thread is a helically shaped groove formed on the cylindrical surface of a workpiece. Thread cutting is an operation performed on a lathe to produce threads by using a tool whose shape will be the same as that of the thread. Types of screw threads, Screw thread nomenclature, Lathe setting for thread cutting, Types of gear trains Simple gear train Compound gear train. Drilling: Drilling is the process of making holes in the workpiece with the help of drill tools.
The drill is held on the tailstock and the drilling operation is carried out by advancing the drill in the workpiece by rotating the handle of the tailstock. Boring: The process of removal of stock from a hole in the workpiece is called boring. Holes are bored by the single point tool. The cutting tool shaves off a thin layer of material to accurate size.