Explain the instruments used in the alignment test on the lathe.

What is the need for an alignment test for a machine tool?

In plan and elevation, the tool must travel in a straight line parallel to the work piece’s axis of rotation.

The axis connecting the centers of the headstock and tailstock must be parallel to the tool travel.

The cross slide, and hence the tool, must travel on a line perpendicular to the workpiece’s axis of rotation.

The following are the instruments;

  • Test Mandrels:-

Hardened, precisely ground, and stress-relieved cylindrical rods are used to monitor the actual running of spindles, relative movement of surfaces, and so on.

They are composed of high-quality alloy steels that have been heat-treated for optimal stability and wear resistance. The mandrel’s surface is precisely honed and lapped to a fine polish.

To improve wear resistance, the surface may be coated with hard chromium. The mandrel’s length ranges from 50 to 500 Hun.

The diameter of the mandrel is often kept low to decrease its weight and prevent the supported length from sagging owing to its own weight.

Larger diameter mandrels can be hollowed out to save weight, but this should not come at the expense of the mandrel’s rigidity.

  • Dial Gauges:-

In most cases, dial gauges with magnetic supports and a measurement precision of 0.01 mm are enough. To conduct the testing the dial gauges must be mounted on a strong frame with enough bearing surface to prevent displacement caused by jerks, vibrations, and so on.

The plunger pressure should be just enough to give a positive result without producing any deflection of the test mandrel or the machine element it is contacting.

  • Straight Edges and Squares:-

Straight edges and squares for the testing should ideally be made of cast iron or steel. They must be of sturdy design, properly ribbed, and free of internal tensions in order to perform accurately.

They should have a big enough bearing surface and a tight tolerance with a squareness of the order of 0.01 mm.

  • Spirit Levels:-

Precision is required for spirit levels used to assess the flatness of surfaces. Levels with a sensitivity of 0.03 – 0.06 mm per meter are frequently recommended.

The base’s length should be as long as feasible, ideally not less than 200 mm. There are two sorts of spirit levels: (1) horizontal spirit levels and (2) frame levels.

The frame level is a square-sided frame with spirit levels attached to the base. To fit against, one of the block’s vertical sides is machined in the shape of a v.

The block square is used to assess the flatness of beds and columns in horizontal and vertical planes. A regular spirit level and a try square can be utilized in the absence of a block square.

  • Autocollimator:-

Optical square autocollimators can serve as very sensitive IDS, horizontal, vertical, or inclined planes.

Live your life to the fullest with a lot of madness because once you lose your childish nature your life will be over.


“Travel as much as you can with your friends and family to enjoy the journey of life, if you want to know yourself more, travel solo” – kp

Once you stop exploring, you are dead alive


Helping Hands.

About the author


You can download our apps and books for free..
Search - Incognito Inventions

View all posts

Leave a Reply

Your email address will not be published. Required fields are marked *