Jim Thompson wrote:
Does this type of "hook/latch" exist?

http://www.analog-innovations.com/SED/BarStockClamp.pdf

I want to push a piece of bar stock into it and have it latch in
place.

Light load... maybe 2-3 pounds.

...Jim Thompson

It looks sort of like a fence gate latch. But it'll probably
be easier to make one out of an L bracket, than to find one.

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||_____O_ - epoxy a nail near the end
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Drawn without the upper plate in your diagram. If that plate
is necessary, just use 2 L brackets, cut and drill:

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||'-----
||_____O_ - epoxy a nail near the end
'--------

And simplest, an L with a hex headed bolt:

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'------O-
L
T

The one above is how I hang my 36' extension ladder. The head
of the bolt is enough to ensure it _cannot_ slide off accidently.
You have to lift it up a bit, then you can move it away from
the wall.

Ed