wrote in message
ups.com...
If they all happen in one area, it's likely that there's something
inside stopping the screws from going in any further.

Actually no, I can see the screws going thru the metal. I only need
about 1/16 - 1/8" to get the dimple, but they spin out before then.
They are 1-1/4" screws; I'll try shorter ones..

Thanks.


If you looked at a cross section of the metal beams, are the corners
perfectly square, or do they sort of fold back a bit toward the interior
(probably not explaining that well....sorry)?