Working Principle of Lathe Machine

Working Principle of Lathe

• The tool moves parallel to the workpiece's cylindrical surface to form a cylindrical surface.
• The tool moves inclined to the axis to produce a taper surface, called taper turning.
• The work is held between two supports called centers, or by a chuck or face plate mounted on the machine spindle.
• The cutting tool is held and supported on a tool post.
• The job moves in rotation about the spindle axis, and the tool is fed against the revolving work.
• The tool movement can be either parallel to or at any inclination to the work axis.

Specifications of Lathe

• Height of centers, type of bed (straight, semi-gap, or gap), and center distance.
• Swing over bed, swing over cross slide, swing in gap, and gap in front of face plate.
• Spindle speeds range, spindle nose, spindle bore, and taper nose.
• Metric thread pitches, lead screw pitch, longitudinal feeds, and cross feeds.
• Cross slide travel, top slide travel, and tool section.
• Tailstock sleeve travel, taper in sleeve bore, and motor horsepower and RPM.
• Shipping dimensions including length, width, height, and weight.

Types of Lathes

• Engine Lathe or Center Lathe: most common type, widely used in workshops, and allows for variable spindle speed.
• Bench Lathe: small, mounted on a workbench, used for making small, precision, and light jobs.
• Speed Lathe: high-speed, hand-operated, used for wood turning, metal spinning, and other operations, with a spindle speed of 1200 to 3600 rpm.
• Tool Room Lathe: designed for accuracy, used for manufacturing precision components, dies, tools, jigs, etc.
• Special Purpose Lathes: custom-tailored for particular needs, used for heavy-duty jobs, and includes types like Gap Lathe, Instrument Lathe, Facing Lathe, Flow Turning Lathe, Heavy Duty Lathe, and more.
• Turret Lathe: an adaptation of the engine lathe, where the tail stock is replaced by a turret slide, and the tool post is replaced by a cross slide.
• Capstan Lathe: similar to turret lathe, but with a movable turret, used for fast production of small parts.
• Automatic Lathe: a lathe where the workpiece is automatically fed without operator intervention, requiring minimal attention after setup.
• CNC Lathe: a high-tech lathe with a computer numeric control system (CNC), allowing for automatic tool change, high accuracy, and fast production.

Lathe Operations

• Turning: to remove material from the outside diameter of a workpiece to obtain a finished surface.
• Facing: to produce a flat surface at the end of the workpiece or for making face grooves.
• Boring: to enlarge a hole or cylindrical cavity made by a previous process or to produce circular internal grooves.
• Drilling: to produce a hole on the workpiece.
• Reaming: to finish the drilled hole.
• Threading: to produce external or internal threads on the workpiece.
• Knurling: to produce a regularly shaped roughness on the workpiece.
• Parting: to cut the workpiece into two, similar to grooving.
• Chamfering: to bevel sharp machined edges, making assembly easier and improving aesthetics.
• Drilling: a process of creating a hole on the workpiece having a certain depth.