I have about decided to start over and construct this from scratch, by measuring from one of the other sketches, and constraining this as I go.

I've learned enough from the discussion to think that I might be able to do this.

So I have some questions:

I have a horizontal and vertical line set crossing at some point. Unfortunately, it appears that this is in the ZY plane, rather than the XY plane.

How do I change the planes?

I have set symmetrical constraints on the center points of the circles, and the line at 90 degrees to them, so they are constrained symmetrically, and

I have set the distance between them to the proper values.

Secondly, I have established point on object constraints for the center points of the 4 circles.

1. What kind of constraint do I need to put on the 4 of them, so if one is changed, they are ALL 4 changed?

2. I have a left hand arc built. I want to mirror it to the other end of the sketch (the right side,) and flip it and lock it in the same relationship to the

center point of the small arcs, and set so that if the left arc radius is set, it will change the right arc radius., but such that it matches what what has been done so far.

How do I do that? I find no easy way to select an object, and flip it along the vertical axis, like I can in most drawing programs.