A barber is a professional who cuts and styles hair. To do his work effectively, a barber requires certain tools and equipment. Let's analyze each option to determine which one a barber would not need:

a) Comb:
A comb is an essential tool for a barber. It is used to detangle and section hair, making it easier to cut and style. The comb helps the barber achieve precision and control while working.

b) Scissors:
Scissors are an indispensable tool for a barber. They are used to trim and cut hair to the desired length and shape. Different types of scissors, such as shears and thinning scissors, are used for various cutting techniques.

c) Chair:
A chair is an important piece of equipment in a barber shop. It provides a comfortable and adjustable seat for clients during their haircut. The chair's design often includes a hydraulic lift for height adjustment, a reclining backrest, and footrests for convenience.

d) Potter's wheel:
A potter's wheel is not required for a barber's work. It is a device used by potters to shape clay into various pottery items, such as bowls, plates, and vases. The potter's wheel is not related to the cutting or styling of hair, so a barber would not need it.

In conclusion, the correct answer is option 'D' - Potter's wheel. A barber does not need a potter's wheel to perform his work of cutting and styling hair. The essential tools for a barber include a comb and scissors, while a chair is necessary for the comfort of the clients.