Hard surface modeling likely will require a series of bolt or screw heads to be strewn around the scene. You can probably find free models to use, or even a generator of some type to create them. Still, there is nothing like knowing the foundations of how to build bolt and screw heads from scratch. Building them well, with proper topology, quickly, is another story.
Luckily C4D users have the Make It Look Great (MILG) series from MotionWorks. In fact the 11th installment in the series looks at Hard Surface Modeling Tactics. MILG 11 is hosted by London-based 3D artist Toby Pitman, who has a deep understanding of modeling concepts and techniques.
A couple of sample excerpts from MILG 11 are how to quickly and efficiently create a hex bolt head, and a Phillips style screw head in C4D. The Philips screw head is something that is a challenge for 3D topology for sure.