Here's a follow-up, for the record:

I went through a few (expensive) boxes of fasteners before finding something
I trusted.

Regular wing-toggles were no good. For one thing, they require a huge hole
relative to the size of the bolt. For another, you can't install the anchor
independently from the bolt and the fixture -- and I didn't want to wrestle
with getting a dozen toggles into their holes while holding the wall cleat
in the air.

The EZ-Toggles were a disappointment. They can only handle a wall thickness
of up to 5/8", and when they're going through 5/8" drywall _and_ a steel
stud flange, the toggle didn't always pop open inside the wall. That's a
pain, since it can't be fixed without taking everything off the wall. Some
of the walls in question also had two layers of 5/8" drywall, so these
wouldn't work anyway. Last, the bolt that goes into the anchor is pretty
skinny.

Fat sheet metal screws -- the self-drilling kind -- were no good. They had
hardly any pullout resistance. Maybe the self-piercing kind would have
worked better.

Finally: Toggler brand toggles (http://www.toggler.com/toggle.html). These
were good. They're easy to install, since the anchor is installed on its
own, without the bolt. For a 1/2" hole in the wall, I got to use a large,
reassuring 1/4-20 bolt. The anchor itself is substantial, and has actual
threads, so it's more like a nut than any other anchor. I found them locally
(Ottawa, Canada) at Fastenal (http://www.fastenal.com). I think HD carries
them in the States.

-Chris.

"Chris Solar" csolar AT magma DOT com wrote in message
...
The largest section of shelving is 65" wide, 37" tall, and 9" deep. It has
three rows of books (183 linear inches of bookshelf), so almost 300 pounds
for a fully-loaded unit based on my measurements. It's hanging up near the
top of a 9' ceiling,