jsburger wrote:America's Funniest Video's seeks out those videos. They are not shown because there is a problem, but, because they are "funny".
In a house that old, if they are 2x4's they are a full 2" by 4", not what we have today. The ceiling is tongue and groove oak. That distributes the waight on any rafter over many more.
Of course AFV seeks out these types of video but think for a moment. If it happens often enough to be caught on tape as often as AFV shows one of these swings pulling out, how often is it happening when nobody is video taping it?
Also AFV doesn't show any video where people are seriously injuryed so how many accidents have happened where people were seriously injury like the lady I saw. Imagine falling down like that, think what it could do to your spine alone.
I have seen more than one 2x4 rafter break with just one carpenter standing on it during house construction. Who knows where a knot is and boring into a 2x4 for the lag screw is going to weaken the lumber. Also as someone else mentioned perhaps there is insect or termite damage.
Since swings usually sit toward one end or another on a porch it should be relativity easy to pull enough of oak T&G loose to run some stretchers across the rafters and then used lag bolts with sizeable washers to anchor the swing.
Personally to me building an "A" frame similar to the type used for swing sets and using 4x4's or heavier timber to hang the swing from would be easy and cheap. Then there is no danger, the house is not damaged, the swing can be moved if desired.