PLA isn't the best material for this. I printed 2 of these. I got around 15 full 2 hour uses out of each one.

Plastic screw for the WEED EATER model 317. Also known as a Lawn Trimmer. I printed the part 3 times. Adjusting the screw holes width from 4.5mm to 5.5mm and changed the direction of the threading from right to left, which seems to have done the trick. In the image with the 3 parts, you can see the yellow is the original part and the 2 white parts of the failed parts for the screw hole.

Printed with PLA with Support around the bottom edges.
Modeled in Fusion 360.

The Lawn trimmer was a hand be down and am very happy to share this replacement part for anyone else who may find themselves in the same situation of needing to replace the screw.