One morning, I woke up and tried to turn on the shower, only to find that the tiny plastic part connecting the handle to the water valve shaft had broken, and the entire knob was spinning in vain. "Damn it," I thought, "let's model it in CAD!"

After measuring it with a caliper and printing the test piece, the new knob started to print. Before noon, my shower was fixed! :triumph:

I'm providing the Onshape document link here so that you can adjust the dimensions to suit your specific situation. This needs to fit a 7/16-inch shaft and have a 3/16-inch overall key.

(I suggest printing only the interface part for testing first, and then printing the entire knob later.)

https://cad.onshape.com/documents/4dcff09d37e1da6aec3aa424/w/961981268e70566f78a0ede3/e/33827ca64e7487a8c7e45258?configuration=List_nBtJwzT4eWfHbr%3DDefault&renderMode=0&uiState=6776d0dd5e874333434df0b1

I wish you a pleasant experience using it!