I won a wooden porch swing in a contest, not one I'd have bought but still I figured I'd put it in the backyard so I went out & picked up 3 4x4's & some cement. I'd set the 2 posts about 6' apart (it's a 4' swing) & was going to lag bolt the last 4x4 across the top of the 2 posts. My wife comes out & says "Is that going to be strong enough?" Well I say "Of course it is!" & she goes back in the house. Now though I'm wondering & I hate that. So what kind of load can you put on a treated pine 4x4?