An efficient database design for recording complex contact/configurator form
You have three questions here.

Storing multiple rows (of components) per form submission. This will happen in any process flow of a manufacturer. It is possible and you shall normalize by adding more rows per form (even for a component).

Secondly, each screw / component having its own set of (duplicate) fields can be handled simply by making those components refer to the existing data itself just by adding another sub-item id as required.

And for your main question of "how should I design my db tables", it is better if you could present a design and your expected bottle necks / issues / hurdles / etc. for which we shall suggest solutions.