todd wrote:

Unfortunately, it has a moment of inertia (even assuming there are 2 of them
as the poster suggested) about 350 times less than the shelf.

Oh, certainly. I should have maybe qualified that statement.

That 1/2" angle iron gives about as much strength as a 1/2"x2" lip of
oak under the shelf.

i.e. not very much.

Yep.

Of course, if you put the 2" dimention vertically under the shelf, the
lip is about 16x stronger.

Of course, if the lip is made of tungsten carbide, it would be 30x stronger.

True. But I think my suggestion is more practical. grin

It's also directly proportional to the cube of the length. If the OP could
reduce the width just 6", the deflection would drop about 25%.

Yep.

It was kind of fun digging up my old statics references--I trained as an
engineer, but I've been doing software for the past 6 years.

Chris