I am trying to come up with a way to design two flat aluminium parts to allow these to rotate in the same plane, but I seem to lack the proper words to find more information on this.
I'll illustrate what I mean with this practical example of a LEGO brick which does just that. (I figured this was the easiest way to show what I mean, since I have these at hand.) Here are two of these common hinge bricks on top of each other:
What is this type of flat hinge called?
Searches for 'flat hinges' lead to normal vertical hinges with a flat mounting profile. I wonder if I'm missing some really obvious terminology here.
Now consider making these out of aluminium, scaling them up to perhaps 500 mm in length, and perhaps making them even 'flatter' — maybe 40 mm thick? Each side of the object could have two or more protrusions which would interleave when the 'hinge' is assembled. Again, a bit like how these two stacked halves of this LEGO brick look:
The resulting item can be picked up, and would typically be hinged open and shut by someone holding both sides (unsupported by any surface) in a (near) horizontal position like the brick above. In closed state, the hinge would not be the only point of support (unlike this LEGO brick). The hinge should be strong enough to hold one side floating without breaking. The item does not need to support anything but itself — similar to picking up the above LEGO hinge, and pushing it open with a finger while holding one side in the other hand.
If I make an object of this type with an interleaving hinge design like the above, I figure I would have to add a separate pin to connect the two parts (the LEGO brick does this with a split pin as part of one halve of the hinge brick).
Are there particular materials best suited for such a pin?
How can I make the hinge operate smoothly? Would a little lubrication suffice?
How can I determine the (ballpark) surface size of the interleaving parts and the pin diameter to prevent flexing at the hinge?
Is there some resource I can consult which holds the key to answering these questions? Even just the right words to search with would help.
