Mechanical tools

  Lathe accessories -4 jaw and 3 jaw chuck . corridor of a 4 jaw chuck and 3 jaw chuck .features of a 4 jaw chuck and 3 jaw chuck   4 jaw chuck The four jaw chuck is also called as independent chuck, since each jaw can be acclimated singly; work can be trued to within0.001"or0.02 mm delicacy using this chuck.   This type of chuck is much more heavily constructed than the tone- centering chuck, and has much lesser than holding power. Each jaw is moved singly by a square thread screw. The jaws are reversible for holding large periphery jobs. The independent 4 jaw chuck has four jaws, each working singly of the others in its own niche in the chuck body and actuated by its own separate square threaded screw. By suitable adaptation of the jaws, a workpiece can be set to run either true or eccentric as needed.   To set the job for the alternate time, it can be trued with the help of a dial test index.   The check on the workpiece should be carried out n...

  Feed mechanism of lathe . the parts of the feeding mechanism . functional features of the feeding mechanism Feed mechanism The feed mechanism of a lathe enables automatic feeding for the tool longitudinally and transversely as needed. By automatic feeding the finish on the work will be better, the feeding of the tool will be at a uniform by continuous rate and it takes less time to finish the operation while manual labour is avoided. The feed mechanism comprises Spindle gear Tumbler gear unit Fixed stud gear Change gear unit Quick change gear box Feed shaft/lead screw Apron mechanism The proportionate tool movement for each revolution of work is achieved through all the above units of the feed mechanism. Spindle gear The spindle gear is fitted to the main spindle, and it is outside the headstock casting. It revolves along with the main spindle. Tumber gear unit The tumbler gear unit itself is of three gears, having the same number of teeth and  it contacts the  spindle ...

  Lathe cutting tools-tool angles and their functions . functions of angles and clearance given on the cutting tools . the angles of a lathe cutting tool . the characteristics of a rake angle . the characteristics of  a clearance angle The tool acts like a wedge during turning. The wedge shaped cutting edge penetrates into the work and removes the metal. This necessitates the grinding of a tool cutting edge to a wedge shape. When we sharpen a pencil with a pen knife by trial and error, we find that the knife must be presented to the wood at a definite angle, if success is to be achieved. If, in the place of a wooden pencil, a piece of soft metal such as brass is cut, it will be found that the cutting edge gets crumbled. For tha blade to cut the brass successfully, the cutting edge must be ground to a less acute angle. Angles ground on a lathe cutting tool All the angles may not be located or found in every tool. As an example a roughing tool is chosen. The angles and clearance...

  Types of cutting tools for lathe . the different shapes of cutting tools used for lathe operations . the characteristics and uses of different shapes of lathe tools. Cutting tool -classification - single point cutting tools - multi-point cutting tools Form tools. Single point cutting tools have one cutting edge which performs the cutting action. Most of the lathe cutting tools are single point cutting tools. Single point cutting tools used on lathes may be grouped into: -side-cutting tools -end -cutting tools Side cutting edge tools have their cutting edges formed on the side of the cutting tool, and are used on lathes for most of the operations. They are again classified as right hand tools and left hand tools. A right hand tool operates from the tailstock and towards the headstock, and a left hand tool operates from the headstock end towards the tailstock. The cutting edges is formed accordingly. End -cutting tools have their cutting edge at the front end of the tools and are u...

  Cutting tool materials . qualities of good cutting tool material . characteristics of cold hardness, red hardness and toughness . the factors to be remembered when selecting tool material . the different tool materials . the characteristics of different tool materials Cutting tool materials Tool materials should be : -harder and stronger than the material being cut -tough to resist shock loads -resistant to abrasion thus contributing to long tool life. Cutting tool material should possess the following qualities. - cold hardness -red hardness -toughness It is the amount of hardness possessed by a material at normal temparature. Hardness is the property by which it can cut/scratch other metals. When hardness increase, brittleness also increases, and a material, which has tooo much of cold hardness, is not suitable for the manufature of cutting tool. Red hardness It is the ability of a tool material to retain most of its cold hardness properly even at very high temparature. While m...

  Lathe parts-Tailstock and Main spindle . the parts of a tailstock . uses of tailstock . functioning of a tailstock . functions of the main spindle . features of main spindle Tailstock It is sliding unit on the bed ways of the lathe bed. It is situated on the right hand side of the lathe. It is made in two parts namely tha base and the body. The base bottom is machined accurately and has 'V' grooves corresponding to the bed-ways. It can slide over the bed and can be clamped at any position on the bed by means of the clamping unit. The body of the tailstock is assembled to the base. Gradutions are marked on the rear end of the base and a zero line is marked on the body. When both zero lines coincide the Axis of the tailstock is in line with the axis of headstock. The body and base are out of cast iron. The parts of a tailstock are -base(a) -body (b) -spindle (c) -spindle locking lever(d) -operating screw rod(e) -operating nut(f) -tailstock hand wheel (g) -key (h) -clamping nut(...

Lathe parts- carriage and tool post . the function of a carriage . the parts of a carriage . commonly used types of tool post . features of different types of tool posts Carriage is the feature of a lathe that provides the method of holding and moving the cutting tool. It can be locked at any desired position on the lathe bed. It consists of two major parts namely, apron and saddle. Apron The apron is botled to thee  front of the saddle. It contains mechanisms for moving and controlling the carriage. The main parts of an apron are: -traversing handweel -feed lever -feed selector -lead screw engagement lever Saddle It is a 'H' shaped casting having 'V' guide grooves at the bottom face, corresponding to the lathe bed-ways for mounting on the lathe bed and for sliding. Parts of a saddle Cross -slide The cross -slide is  mounted on the top of the saddle, and it provides cross movement for the tool. This is fitted at right angles to  the bed and is moved by means of a screwe...