Different types of tools uses

Different types of tools uses.

A large variety of tools are used in center lathes in view of the large types of surfaces that are generated. The actual type of tool used depends upon the surface of job being generated as well as the workpiece. A variety of tools used for normal generation of external surfaces are shown in Figure. Similar tools will be available for generating the internal surfaces as well. The choice of a particular tool depends upon the actual surface to be generated as shown in Figure.

Tool used for external surface

Tool used for internal surface

The tools have the primary cutting edge by means of which the direction of the movement of the tool for removing the metal is indicated. The direction is termed right or left depending upon the movement direction. The tool is termed right when it cuts during the movement towards the headstock. It is derived by the fact that when the right palm is placed on the tool, the direction of the thumb indicates the direction of tool motion similarly, the left - hand tool cuts during its motion in the direction of tailstock.

The variations in the type of tools are indicative of the variety of applications for which these tools are used. The large variety is needed because of the large number of surfaces to be generated. For example, by the side - cutting edge angle of the tool, it is possible to know the application of pockets for which the tool could be used. Similarly, some tools would be required for facing applications while others are used for boring.

Form tools are generally used for machining short profiles. Figure shows two types of typical from tools that are generally used. The circular form tool shown in Figure is held in a holder mounted on the cross slide. The center of the tool should be mounted slightly above the center of the workpiece in order to get a clearance angle such that the tool will not rub the work. The circular form tool has a long life as it can be continuously sharpened over 270 ° of the tool as shown in Figure. The straight or flat - form tool shown in Figure is the simplest type. It is sharpened by grinding top face that reduces the strength of the tool.

Circular form tool

Straight form tool

As of now, a majority of the tools are used of the cemented carbide type with indexable insert type. It, therefore, becomes necessary to understand the Iso coding systems for these to be able to easily make the selection. The ISO coding system (as per ISO 1832 - 1991) for tungsten carbide inserts and external tuning tools is shown in extracted form in Figures.

ISO coding system for turning

ISO coding system for external turning

The actual selection of the tools for a particular application has to carefully match the geometry. Generally, the manufacturer's catalog provides such application information. For example, the use of PDINR type tools for the external turning requires that the maximum contour angle be 30 ° as shown in Figure. It also shows the other type of features that can be machined by the tool. Figure shows the capability of internal turning tools to produce the contour bores. Similar capability charts can be found in the manufacturer's catalogs for the range of cutting tools available.

Contour capacity of external turning

Contour capacity of internal turning