On 9/1/2015 3:46 PM, Vic Smith wrote:
On Tue, 01 Sep 2015 14:39:22 -0700, Don Y
wrote:

Hi,

We have a "double wide" (17'?) *insulated* garage door. As such, the
internal structure of the door is largely hidden.

Across the length of each of the "panels", a metal "stiffener" is
attached. Essentially, like a metal 1x3 fastened "edge on" for
greatest rigidity.

All of the fasteners to the door itself are large, but short, "sheet
metal screws". There seem to be certain places in the door where
"internal members" are present -- beyond just the sheet metal "skin".
So, only screws installed in these locations can actually carry any load.

These seem to work their way loose over time. Making the INEVITABLE
mistake of trying to lift (or lower) the door by grabbing onto one of
these stiffeners invariably ends up loosening screws that attach it
to the door panel.

As they are sheet metal screws *and* the interior of the door is
inaccessible, there's no real way to tighten them; you end up
having to move to the next larger screw size.

[There's a limit as to how far you can go with this!]

Short of putting carriage bolts *through* the door (the exterior is
"smooth"), what other approaches can I take to secure the stiffeners,
hinges and other hardware to the door panels?

You can use Loc-tite. Might help. But you should install a handle
and stop using the stiffeners - or an electric garage door opener.

I suspect loctite would offer too little assistance. The screws are
~1/4" diameter with very coarse threads. They make 1/4-20 bolts look
"fine"!

The stiffeners are rarely used -- they are just the obvious temptation
when the opener is disengaged (perhaps once a year?). And, even ignoring
the stiffeners, there is still the problem of the screws holding the hinges
working themselves loose.

As there are only fixed places on the panels that are reinforced (i.e.,
capable of carrying any focused load), a handle would have to be mounted
vertically:

-+
|
|
-+

instead of horizontally:

+----+
| |

and, only in one of the five places where the panels are reinforced
(two edges, center -- which is where the opener carries the load -- and
midway between center and edges)