I would say failure can delay the work but should not ruin the item.
The math is horrifically harsh if you do. If the player has just a 5% chance of failure, and you make him roll once a day on a 5 day piece of work...that is a 22.6% chance he will ruin it. No one would ever craft anything with those failure chances.
The math is horrifically harsh if you do. If the player has just a 5% chance of failure, and you make him roll once a day on a 5 day piece of work...that is a 22.6% chance he will ruin it. No one would ever craft anything with those failure chances.