dpb wrote:
buck wrote:
OK here's one for you mechanical engineers out there........... I want to
screw two (2) screw eyebolts into an overhead 2x4 rafter. ...
"Would these two screw eyebolts
hold up to 400 pounds (share 200 pounds each)? ...
The eyebolts that would be used are 3/8" diameter and 3 1/2" - 4" long.
...

I don't have any doubt about the bolt itself, and it would likely hold
200 lb in tension on a 3/8" lag bolt (that's essentially an eyebolt),
but I'd first be concerned of the span of the 2x4 rafter (or lower
truss chord). I'd not trust it as a mounting technique if I were
hanging from it or underneath a suspended load, though.


I agree the bolt should be fine but I would thru-bolt with a washer and
nut on top or one of the ideas dpb gave. But not with a 2x4 rafter!

What is the distance the rafter is spanning?
what is the slope of the roof?
is the rafter realy a ceiling joist that is part of a truss?
Is it a finished ceiling (drywall)?
Could you put a beam perpindicular to spread the load over several
rafters?
Could you sister a larger rafter like a 2x6 or 2x8 to the 2x4?