Interesting Alan! Would you mind sharing a picture of one of your robbing screens? I'm thinking about trying to make some this year, and I'm shopping around for ideas. I have some prefab ones, but they are pricey to buy, and as you mentioned, a really nice piece of equipment to have around.
Haha! My screens are REALLY complicated! (Not!).
I bought a roll of replacement Stainless Steel window screen from Home Depot for about $4. A pair of scissors and a box of thumbtacks finished off the requirements. (1 roll of screen can do dozens of hives).
That's all I've used since then, screen and thumbtacks. Very cheap, very easy - and works. Even works for moving hives.
Here's a Pic of one of my early attempts ( I used staples on this one).
I've opened the entrances more now - based on what they need, as viewed by conjestion. I'll try to get a more current picture for you tomorrow.
Also, I've switched to #8 hardware cloth now. Didn't have it available when I had my 1st emergency situation, so I grabbed what was available.