My wife had one of the spring loaded golf ball retrievers. They are pretty clever, but the weak point is where the head is connected to the handle. Of course, it broke. I saved the telescoping handle and decided to make my own head with a stronger mount. I wanted it to be uncomplicated, easy to print, and functional. This seems to accomplish all three. The large opening is used to scoop the ball. The cavity is quite a bit larger than the ball, so the ball stays in quite well. There is a little lip on the inside of the ball opening to help retain the ball. The other end is a smaller opening to drain water or mud.

The hole for mounting fits snug on my handle (approx. 9.7mm). If yours is a different size, you might have to enlarge or reduce. I've included the Sketchup file so you can change as necessary.

Once printed, just slide onto your handle and drill a hole in the handle by drilling through the small hole in the mount. I used a 2-56 machine screw to mount.