Inserts for use in table saws are disclosed. One embodiment may include a mechanism to lock mechanically and affirmatively the insert in a blade opening in a table saw. The mechanism is designed so that a user can install and remove the insert without tools. The mechanism also can be designed so that the front of the insert pops up above the table when released from its locked position. The mechanism can be further designed so that the insert can be unlocked or released by a user pressing a button or tab.