This is when a punter plays consistently for profit without surpassing a set limit and without risking much. A grinder or a rounder is the kind of player who will play a limit beneath his ability to be sure that some or all of his income is recovered even if he is in a position to risk more.

Another meaning to this term is when you work up on your bankroll on a lower limit after you encounter financial hurdles on a higher one. This is where people say that the punter is grinding through his limits.