Does a hard working employee make a good supervisor?

No to be a supervisor you must be a leader , in life some people are followers and others are leaders.Some hardworking people work well only under good leadership and would not cope as a supervisor.

not necessary

No.
Hard working staff, in any industry, are the mainstay of that industry.
However, they need to see the big picture, from the perspective of the worker and the company.
They have to be able to empower the worker to carry out the wishes and targets of the company.
Not everyone is cut-out to be a supervisor.

As supervisor is a leadership position, where the individual is expected to manage others, being a hardworking individual does not guarantee success in this position. 

The qualities required are : Being fair, understanding, logical, mature, ability to deal with difficult situation sensibly, setting an example for his team, punctual, organised, ability to delegate duties to the right person,  encourage team spirit, so that all the individuals under him work toward a common goal.  Of course, the supervisor should be hardworking to set an example for his subordinates to follow.

i disagree.
The reason is that hardworking, punctuality, dedication are the personal characteristics of an employee.
The degree of improvement is in the hand of the employee himself/or herself.
While in case of supervising, the performance of supervisor is associated with the performance of the subordinates.
His Jobs is not only to get out work optimally but also to keep them on track.
Which is a really hard Job.