How can I get my son to hold his bottle?

My 7month old son refuses to hold his bottle of milk. I try and he screams the house down, I have left it a few weeks not to stress him out and he just repeats the screaming. Any tips? Also now he's got 2 teeth and more coming through I'd like to wean him onto a beaker, (which he also screams blue murder at) can anyone help?!