Lathe and Turning Services

Parts of a Lathe

Lathes were first used around 1300 BC but without parts like the headstock and tailstock.  

They may have even been used in Mycenaean cities going back to the 13th or 14th centuries B.C.  

The first major innovations in lathes happened in 1751 when Jacques de Vaucanson invented a all-metal slide lathe, and when mechanized power was available to drive the shaft of the lathe and allow for faster, more accurate work.  

In the 1950’s CNC or computerized numerical control was added to lathe machines to allow for even more optimized work.

Parts of a lathe are:

The lathe bed is the main body of the machine, with all main components mounted on it.

Beds are usually made of cast iron, for its high compressive strength.

Chucks hold the workpiece, fastened on the spindle as they both rotate.

Four and three jaw chucks are used, according to machine requirements.

The holding device is called the headstock, placed at the left side of the bed.

Holding the tools in an accurate position is accomplished by the tool post, fastened on the carriage.

Lead screw, also known as power screw, is located at the bottom side of the bed and is used to move the carriage during thread cutting operations.

Located between the head and tailstock is the carriage.

It moves on guideways and holds and glides the toolpost horizontally and vertically.

Legs support the lathe and help prevent vibration.

Hanging over the front side of the lathe bed is the apron.

It provides power and hand feed capability to the carriage and cross-slide.

The movement of the carriage and tailstock is confined by the guideways.

Spindles hold and rotate the chuck.

On the right hand side of the bed is the tailstock, which locks the workpiece while drilling operations are performed.

It also supports the job when required.

The compound rest fixes the single point cutting tools.

A hand wheel is used to move the tailstock backward and forward.

Movement of the carriage along the lathe is managed by the feed rod.

Machine operations of a lathe

• Drilling
• Reaming
• Boring
• Counterboring
• Taper boring
• Tapping
• Undercutting
• Internal Thread cutting
• Parting-off

Turning is used to remove excess material and resize the material.

Straight turning uses a tool parallel to the lathe axis, producing a cylinder.

Rough turning is used to quickly remove material 2-4mm deep.

Turning produces a step from one diameter to another, working on this step is called shoulder turning.

Eccentric turning uses two separate axes of rotation, with the first axis offset to the second.

Taper turning produces a uniform cone from one diameter to another.

Reducing the length of the workpiece by moving a tool along the height of the center of the workpiece is facing, it produces a flat surface on the end of the piece.

Chamfering creates a bevelled surface at the edge of the workpiece, often used on bolt and shaft ends.

It helps to avoid damage to the sharp edges, and in the case of bolts helps fit nuts and screw them in place easily.

Knurling creates a diamond pattern on the workpiece, providing an improved grip for handheld items.

This operation is performed on the lowest speed settings on the lathe.

Threading like on screws is created by the thread cutting process.

Rotating the workpiece between two centers and moving a v shaped tool along it creates the helical grooves.

Filling is a finishing operation performed after turning, to remove burrs, feed marks, and sharp corners and remove a small amount of metal to bring the workpiece to size.

Polishing with emery cloth after filling creates a smooth, bright surface.

For filling the lathe is run at high speeds of 1500-1800m per min.

Grooving reduces the diameter of the workpiece over a narrow surface.

Shoulders or ends of threads are often used for grooving, as they leave a small margin.

Spinning forms a thin sheet of metal by pressing a headstock spindle against a quickly revolving workpiece.

Coiled springs can also be made by using a mandrel revolved on a chuck or between centers.  

The wire is fed through a small hole on the steel bar winding the spring as the lathe advances.

Turning a convex, concave or irregular shape is known as forming.

It can be accomplished by using forming tools, combining cross and longitudinal feeds, and tracing or copying a template.

Forming is not intended to remove most of the material and is used mainly for finishing.

Straight and circular tools are used for wider and circular surfaces respectively.

Drilling produces a cylindrical hole in a workpiece, by rotating a tool on the cutter side.

Reaming finishes and sizes a hole which has been already drilled or bored, and the reamer tool used has multi-plate cutting edges.

Boring enlarges a hole that has been already punched, drilled or forged.

The workpiece is revolved in a chuck or faceplate and the tools in the tool post are fed into the work.

Enlarging the end of the hole through a certain distance is counterboring.

Shoulder work in external turning is similar to counterboring.

Taper boring uses a boring tool to make a hole that includes a taper.

Cutting internal threads of a small diameter is tapping.

Undercutting is similar to grooving performed inside a hole.

It creates a groove or a large hole at a fixed distance from the end of a hole.

Lathes with special attachments can also perform grinding or milling operations.

Milling removes metal by feeding the work against a cutter with multiple cutting edges.

Grinding removes material by using a rotating abrasive wheel known as a grinding wheel.

Article Refrences:

https://www.theengineerspost.com/lathe-machine-operations

https://en.wikipedia.org/wiki/Lathe

https://engramritkumar.com/lathe-machine/