New revision of our pendulum pell. It uses plastic plugs for the top cap. The center rod is forged on the bottom, allowing a larger hole to be drilled and a screw together key chain to suspend the ring.
The plastic cap works much better than the candle cap I was using, though it does go a little cock-eyed if there is any alignment mistakes anywhere else.
Made a whole box for instructor’s gifts at Fiore Fest. I burned a hole in couple while welding the parts together, but I’m getting good at patching them with filler rod.
It took me two evenings, with most of the effort in the setup. I made 5, but could easily double that number without significantly increasing my effort.
Grauenwolf's Study of Western Martial Arts 
I am interested in the materials that you are using. Specifically the source for the Sphere
or ball aspect of this Pell. What size ball is it and where do you source them. Would love to make one for myself.
My current design uses a 3″ ball from Industrial Metal Supply. The pipe is 1″ I.D. and likewise 3″ long. The rod is 1/4″, with one end forged flat.