základ, základní princip; matice a šrouby

The computer takes care of the nuts and bolts of the composition, the component Dr Mathews calls its predetermined part. (BNC)

That meant that they could not stand the Central Office youths involved in the nuts and bolts of the campaign. (BNC)

Jay comes from a different end of the spectrum to Dave Ambrose, but the two both like to talk nuts and bolts. (BNC)