Some friends gave me a table, but not the nuts for assembly. I belatedly realized I needed it built STAT to host a family dinner, and after two failed trips out to try to get the right size hex nuts (thread size was my downfall), I made these stand ins.

My version was a bit garbage and stringy as you can see in my picture, lol, but I needed them fast, and they've done the job.

Use a 1/2 inch wrench and they'll fit 5/16 inch diameter screws of whatever thread width you need-- just screw them directly into the plastic. I included a bit wider opening on one end to help with alignment.