Knurled nut

Knurled nuts are commonly used in any application where the fasteners will be removed regularly but not needed for structural support.

The advantages of using a knurled fastener in this situation are: it improves the ease of removal, deters the possibly over-tightening/stripping, and does not require any tools to manipulate the fastener.

However, there are knurled nuts available that have a slot cut into them for the use of a Phillips head screwdriver.

This expands the versatility of the nut and provides the option to use tools.

Nuts with the Phillips slot are common in applications where vibration is a concern.