I wanted to make a spinner that had interchangeable arms. So I did. You can have a different body and arm color. The idea was that if you made them for kids, they could trade and upgrade the arms with new ones and have whatever color scheme they like.
Use pennies for the weights. Tip: Use a gram scale or a balance for your sets of pennies to make sure they are very close to the same weight in each arm to get proper balance. Or only use all pennies from the same year or something. The metal composition has changes many times over the years, so they have a pretty large variance in weight.
There's only 1 body design, but 3 different arms are included. The number in the filename like ".01mm" denotes the offset between the dovetail joint in the arm and on the body. I made 3 versions, should accommodate different printers while keeping the size of the holes for the bearings and pennies the correct size.
You may still have to scale body or arm a little to get a tight fit.