Question

Give reason why
Machin part are oil occasionally

Answer 1

to prevent them from rust

Answer 2

Lubricants such as Grease, Oil, and compressed air(also a lubricant) are used in heavy machineries to reduce the friction produced in parts of them. In other words, the friction acting on parts of machines produces heat, due to which they may got damaged or may have reduce in maintenance.
This also prevents them from rust.

Hope it helped you!!