Need Help Correcting drawing.

 

Hi, I'm not sure if this is the right place to ask my question. I contacted support, but the answer I received was too complex for my skill level. A customer sent me a drawing of a part they want to order, but the drawing isn't 100% accurate. I need to correct the drawing so I can mill the contour. I want to place a ring over a circle, which seems simple, but I'm looking for a better method than the one provided by support. Can you help? Dont mind the grooves, im focust on the ring. I included the supports version.