The handle on my Logitech green screen snapped, so I made myself a replacement. The hole for the shaft on the screen itself is 6mm, so you could easily replace the printed version here with a metal rod if you have an ~6mm rod, but I don't have one to hand so I thought I'd try it fully printed and it works nicely.

Printing is pretty straightforward: the shaft has a flat spot for better bed adhesion, but using a brim isn't a bad idea, and the handle itself should be oriented with the largest surface area down.

After printing double check the fit on the shaft with the hole, and with the holes in the handle, and if everything fits well put the handle on the screen and feed the shaft through it. For me the fitment was tight enough on its own, but if the shaft is too loose add a little glue to either side for security's sake.

The shaft itself is a bit flexible regardless of the filament you use, but in place there's little enough exposed on either end that any flex is a non-issue and it seems to work just as well as the original.