However, you could use some descriptive phrases to refer to a group of screws, such as:
* A box of screws
* A handful of screws
* A pile of screws
* A collection of screws
* A set of screws
You could also use more creative phrases like:
* A constellation of screws (if they're scattered around)
* A regiment of screws (if they're all the same size and type)
* A swarm of screws (if they're moving around)
Ultimately, the best collective noun will depend on the context and what you want to emphasize.