The collet chucks is the most accurate chuck and is used for high-precision work. Spring collets are available to hold round, square and hexagonal shaped workpieces.c. Lathe dogs:When work is machined between centers, it is generally driven by a lathe dog. The lathe dog has an opening to receive the work and setscrew to fasten the dog to work. The tail of the dig fits into a slot on drive plate and provides drive to the workpiece.The standard bent-tail lathe dog is the most commonly used dog for round work pieces. These dogs are available with square or headless setscrews, which are safer, since there is no protruding head.
Operations on Engine Lathe: Turning:Turningis the process whereby a single point cutting tool is parallel to the surface.it can be done manually on automatically on a lathe. When turning, a piece of material is rotated and acutting toolis traversed along 2 axes of motion to produce precise diameters and depths. The workpiece is rotated while tool is moved longitudinally with the help of carriage to shear off the metal.Facing:Facing is part of the turning process. It involves moving the cutting tool at right angles to the axis of rotation of the rotating workpiece.This can be performed by the operation of the cross-slide, if one is fitted, as distinct from the longitudinal feed (turning).Taper Turning:Taper turning on a lathe is done by the help of compound slide. Work is rotated while the feed is fed by the help of a compound slide.Parting: This process is used to create deep grooves which will remove a completed or part-complete component from its parent.Grooving:It is like parting, except that grooves are cut to a specific depth by a form tool instead of severing a completed/part-complete component from the stock. Grooving can be performed on internal and external surfaces, as well as on the face of the part.Knurling:The cutting of a serrated pattern onto the surface of a part to use as a hand grip using a special purpose knurling tool.Threading:Both standard and non-standard screw threads can be turned on a lathe using an appropriate cutting tool. Threading generally is referred to as single point cutting.
Drill MachineA drill machine is a fixed type of machine that is used for drilling holes in various metals or fastening various metals together with the use of fasteners.Parts of drill machine:Base:The base is usually made of cast iron, provides stability for the machine and rigid mountings for thecolumn. The base is usually provided with the holes so that it may be bolted to a bench. The slots orribs in the base to be fastened to the base.Column:The column is an accurate cylindrical post that fits into the base. The table, which is fitted to the column, may be adjusted to any point between the base and head. The drill press head is mounted near the top of column.