Bench press,dumbell press and incline bench press is all you need if you want to bulk your chest.
i been doing machine work outs for a long time and i have not noticed any growth in the chest at that time as soon as i started doing the three i mentioned my chest seemed to be growing every workout!!!free weights work alot better then any machine work outs but thats not a secret.
on bench try to increase 1rm so do low reps heavy weight
on dumbell press try to do as much weight as possible in the 6-8 rep range
on incline press do somewhere around 6-8 also
just trowing my two cents in.