Keilim 22:2-3

Keilim 22:2

If one leg is removed from a three-legged table, the table is rendered insusceptible to ritual impurity. If a second leg is removed, it remains insusceptible. If the third is removed, it is rendered susceptible to ritual impurity once the owner has decided to use it. Rabbi Yosi says that it doesn’t require the owner’s intention. The same rules apply to a sideboard.

Keilim 22:3

If one of the two legs of a bench is removed, the bench is rendered insusceptible to ritual impurity. If the second leg is removed, it remains insusceptible. However, if the legless bench is one handbreadth tall (about three inches), it is susceptible. If one leg of a footstool is removed, it remains susceptible to impurity; the same is true of a chair that is used as a stool for an armchair.