gear-tooth

Kindly Dad, you've got a worn gear-tooth.

And he'd probably be in grave doubt as to its validity; he'd probably decide our programming slipped a gear-tooth.

And as it said this, a gear-tooth slipped in the glare of Jack's trouble-light, and a phase of the cycle repeated itself.

A lowboy with three cradles, two of them already holding missiles, waited to receive the third long cylinder clanking gear-tooth by gear-tooth down the conveyor from the magazine on B Deck.