gritting

Example:He gritted his teeth and pushed the wood through the grinder.

Definition:To rub roughly against a hard surface, producing fine particles or dust

Example:She gritted her teeth and dragged the nails down the board.

Definition:To rub roughly along the surface of something, causing it to become damaged or worn

Example:He gritted his teeth in frustration.

Definition:To hold or squeeze tightly, especially the teeth or fists