The differences between these two types of nuts include height and application range.

1. Height: The height of type 1 hexagonal nut is 0.8d, while the height of type 2 hexagonal nut is 1.0d.

2. Scope of application: Type 1 hexagonal nuts are the most widely used and are mostly used for the connection of general light-load mechanical equipment and components, and do not require particularly high tightening strength. Type 2 hexagonal nuts are thicker and are mostly used in situations that require frequent assembly and disassembly.