What Am I Riddles

Question: What has 3 feet but cannot walk?

Question: What fastens two people yet touches only one?

Question: What belongs to you but others use it more than you do?

Question: Poke your fingers in my eyes and I will open wide my jaws. Linen cloth, quills, or paper, my greedy lust devours them all.

What am I?

Question: I am taken from a mine, and shut up in a wooden case, from which I am never released, and yet I am used by almost everybody.

What am I?