mower string conversion

I wanted to convert my 21" mower from a steel blade to a string trimmer. This way if I hit a rock or stump, it will not harm the engine.
This replaces the blade and it fits on a 3/4" shaft.
You'll need to get thick string to insert in the holes.
There are (6) sets of holes to put strings in.
Printed the first one in TPU. 33 hours to print it.