Captive Washer for Hex Bolt, bed leveling

Tired of having to use two hands to adjust Z-axis leveling? This captive washer fixes that problem.
It actually fulfills two functions. First, it spreads the downward force of the leveling screws on the glass bed so that it doesn't break. And, it keeps the leveling screws from spinning as you adjust the knob.

For my implementation on a Tevo Tornado:
1. I printed in PETG, but ABS would work as well. You need to use a material that will remain dimensionally stable.
2. I replaced my printer's socket head screws with standard hex head screws.
3. I put a spot of instant glue between the mating surfaces of the washer and the printer build platform.
4. I used nylon washers between the adjustment knobs and the support frame to reduce friction.

Note that I have removed the factory build surface and replaced it with magnetic rubber to facilitate textured powder-coated spring steel build surface. The black build platform that you see in the photo is the printer's glass