# How to make a circle spin from the edges

I have an issue where I need to make a large wire through a bearing spin in 3" diameter circles, and have a weight hanging from the bottom of the wire. Essentially, I need a hole that moves in a trajectory such that the center of that hole makes a 3" circle path. To make the 3" diameter circles, I was just thinking of having a spinning disk driven by a motor and an arm, and have a circle offset 1.5" from the center. The problem with this is that the motor shaft would be secured in the center of the rotating disk, and there would not be enough room for the weight at the bottom of the wire to spin without interfering with this shaft. One of my ideas was to design some fixture similar to the one shown in this video: https://www.youtube.com/watch?v=VTkULChFXkk. I would have four motors driving holes in the corners of a plate driving the rotation, and put my bushing through the center. Another idea I had was to do something like the following image, where I have 3 or more servos on the edges of a center gear that has the 1.5" offset hole. Would this be secure enough? How would assembly work with this, as I am not too familiar with gears. Would I be able to put the three servos down and then put the center gear down in the middle? enter image description here

• The other post wasn't deleted? I am just trying to work out some other ideas for how to make this work. Unless you are referring to someone else posting something and deleting it. Jan 27 at 14:49
• Sorry. I was rash there. Your two accounts weren't linked and the other question got buried super fast. Jan 27 at 14:50
• the motion can be circular without passing the cable through a circular plate ... web search pantograph ... drive it at the end with a 6 inch wheel ... the cable is attached at middle Jan 28 at 2:58