Excuse my lack of knowledge - best to assume I'm an idiot when answering.
I have a barn conversion and have beams within the walls of the rooms. I want to attach two 10cm square wall plates on two opposite sides within the beams. These need to hold some weight with confidence and I'm wondering if I can simply screw them into the beams or whether I should use a bolt running right through to the other side and secure it on the other side in the next room? How structurally sound are wooden beams generally if a screw is all the way through - are they likely to slip with time? Any thoughts really appreciated.