The word you are looking for is 'fingertight'. When tightening a bolt, you do it up until it's fingertight and then use a tool (Br Eng 'spanner', Am Eng 'wrench'*) to tighten it further. If you want to be precise about how much you tighten it, you use a torque wrench.
Incidentally, the collocation is 'nuts and bolts'; 'bolts and nuts' sounds stilted in most contexts.
PS* It's not quite as easy as this. Some tools (torque wrench, monkey-wrench and Mole wrench spring to mind) use the word 'wrench' in Br Eng. But the generic word is 'spanner'. In fact, an advertisement (a postal franking slogan) that proclaimed 'Newport, home of the Mole wrench' had to be changed - when people objected to a national carrier (which the GPO then was) advertising a commercial product by name - to 'Newport, home of the self-adjusting spanner'.