To move easily

To lift easily

To lower easily

To raise easily

Testing parallelism

Testing straightness

Testing concentricity

Testing eccentricity

White cast iron

Tool steel

High carbon steel

Stress free cast iron or steel

1:2:4

2:1:4

4:2:1

4:1:2

Keep sag with permissible limit

To measure the length of object

To test straightness of the object

To test the level of the object