A taper is the uniform increase or decrease in the diameter of the workpiece and measured along with its length. A taper turning means to produce a conical shape by a gradual reduction in diameter from a cylindrical workpiece.
Taper turning methods
These are the various methods used in taper turning.
Form tool method:
In this method, the taper length obtain is equal to the width of the form tool to obtain the required size of the taper turning the form tool is fed slowly straight into the workpiece by operating the cross slide perpendicular to the lathe axis.
Combined feeds method:
The combined feed is made with the movement of a tool in a longitudinal or lateral direction simultaneously while moving the workpiece.
Compound rest swivel method:
Here the workpiece rotates and the cutting tool is fed at an angle of swiveled 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.
Taper turning attachment method:
This method is similar to the compound rest method. Here the job or the workpiece rotates and the tool is fed at the taper angle.
Tailstock set over method:
Here the workpiece on the job is tilted at the required taper angle. The tool is fed parallel to the axis. This method is useful for small tapers turning.
Turning process in manufacturing
These are various operations in the manufacturing process.
It is an operation for reducing the length of the workpiece by feeding the perpendicular to the lathe axis and reducing flat surfaces on the end of the workpiece. A regular turning tool or facing tool may be used for facing operation. The cutting edge of the tools should be set to the same height as the center of the workpiece. Facing consists of two operations they are roughing and finishing.
It is the operation of getting a beveled surface at the edge of the cylindrical workpiece. It is done in the case of both ends and shaft ends. This operation helps to avoid damage to the sharp edges and protect against getting hurt from other operations. Chamfering on both 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 rollers and it is held rigidly on the tool post. Knurling is done at the lowest speed available on a lathe. It is done on the handles and also in the case of the end of gauges.
Thread cutting operation:
It is an important operation in the lathe to obtain the continuous helical grooves or threads. When the threads and helical grooves are formed on the outer surface of the workpiece is called external thread cutting. When they are formed on the internal surface of the workpiece is called internal thread cutting. The workpiece is rotating between the two centers. The tool is moved longitudinally or horizontally to obtain the required type of thread. The motion of the carriage is provided by the lead screw. A pair of change gears is provided by the lead screw and by rotating the handle the depth of the cut can be controlled.
It is the process of reducing the diameter of a workpiece over a very narrow surface. It is done by a groove tool. A grooving tool is similar to the parting-off tool. It is often done at the end of the thread or adjacent to a shoulder to leave a small margin.
Drilling is the operation of producing a cylindrical hole in a workpiece and it is done by rotating a tool. A rotating side of the cutter is known as a drilling drill. In this operation, the workpiece is revolving in a chuck or a face plate and the drill is held in the tail stock drill holder or drill chuck. The feeding is adapted and is affected by the movement of the tail stock spindle. This method is adopted for the drilling of the regular workpiece.
Reaming is the operation for finishing and sizing a hole that has been already drilled or bored. The reamer tool is used which has multiple-plate cutting edges. The reamer is held on a tailstock spindle either directly or through a drill chuck and is then held stationary while the work is revolved at a very slow speed.
Boring is the operation of enlarging the whole which is already drilled punched or forged and it cannot produce a hole. In this, the workpiece is revolved in a chuck or a face blade, and the tools are fitted to the tool post and fed into the work. It consists of a boring bar having a single-point cutting tool that enlarges the hole. It also corrects the roundness of the hole. This method is adopted for boring small-sized works only.
Counter boring operation:
Counter boring is the operation of enlarging the end of a hole through a certain distance. It is similar to shoulder work in external taper turning. The operation is similar to boring and plain boring tools or counter boring may be used. The speed is slightly less than drilling.
Taping is the operation of cutting internal threads of small diameter using a multiple cutting tool called the tap. In a lathe, the work is mounted on a chuck or a faceplate and revolved at a very slow speed. A tap of the required size held on a special fixture is mounted on a tailstock spindle.
Milling is the operation of removing metals by feeding a work against a rotating cutter having multiple cutting edges. For cutting keyways or grooves. The work is supported on the cross slide by a special attachment and fed against a rotating milling cutter held by a chuck. The depth of the cut is given by the vertical adjustment of the work provided by the attachment.
Grinding is the operation of removing metal in the form of minute chips by feeding the work against a rotating abrasive wheel known as the grinding wheel both internal and external surfaces of the workpiece may be ground by using a special attachment mounted on the cross slide. For the grinding external surface, the work may be revolved between centers or on a chuck. The feeding is done by the carriage and the depth of the cut is provided by the cross slide. Grinding is performed in the lathe for finishing a job sharpening a cutter or sizing a workpiece after it has been hardened.