How to create a datum symmetric midplane between 2 lines

[[Kr...]]

Hello,

 

I am attempting to inspecting an injection molded part. I am struggling with recreating the datum B feature as is designated on the print. 

 

It is a width between two walls that have draft. The drawing calls out datum B as shown below, at a distance from datum A. this gives a concrete width to the feature.

here is a model view of the lines I would like to use to define datum B:

 

I would think creating a symmetry plane between these two lines would be a simple task, but I have not found any function for performing this task. Is there a work around or some way to accomplish this? since the lines lie in the same plane, I would expect the symmetry plane to be perfectly perpendicular to A.

 

Thanks

[[Ch...]]

Dear Kristian, 

it is not possible to create a symmetry plane from lines.
You can create a symmetry plane from planes either - note for the GD&T application the actual data should oppose each other. But the surface are quite small and far from each other so may be the symmetry plane might be instable without further boundary conditions.
Another possibility is to create lines onto that section, from those lines a symmetry line can be created.

[[Ji...]]

Assuming datum B is your secondary datum, create a section 1 mm from datum A.  From this section, create 2 lines.  From these 2 lines, create a symmetric line.  From this symmetric line, create two endpoints.  Then create a perpendicular plane using the two symmetric line endpoints and datum plane A.  This result will be a centerplane perpendicular to datum A as desired.