Just after the birth of our first son we were given in amongst a heap of kids stuff was an old Tupperware Shape'O' Ball with just one handle.
I made a copy of the existing handle in Free Cad and printed it up in translucent PLA on my home scratch built 3d printer.
After designing and building my own 3d printer essentially out of junk I had lying around. Old scanner and a couple of Buble jet printers https://hackaday.io/project/4082-home-made-3d-printer I figgured having a printer was useless unless I had some way of generating the files to print. So imersing myself in the world of cad programs and a minor brain explosion and a distinct dislike for online tools.( I live in a rural town, the best internet we can muster is served up on a couple of barbed wire lines strung betwen the gum trees ) I come accross Free Cad and figgured how hard can ths be...........
The need for the Handle for the Ball was a good motivator to sit down and have a go.
To start with I took the remianing handle and took some measurements and made a bit of sketch on paper and set out to duplicate what I saw.
Bubling along with my first attempt at using a 3d CAD tool I started out with the biggest bit first a circle that defined the outer edge of the handle. The rest is "blending" adding and subtracting a series of circles (or segments of circles) and rectanfgles to build up the shape.
While I got the critical dimensions pretty well right I struggled to get the cut outs for the handle section quiet right. The end result was a vairiation in the thickness of the handle as it curved from the hook to the flat face. This was due to using different origins for the cutouts and the outer circle. While this is quiet obvious in the drawings in reality it makes no difference to the opperation and is barely noticable.