Half diameter in section view

Hello,

I'm student and I have to create drawings exactly like originals. But problem is that I don't know how to create dimension - half diameter with dimension tool.

I enclosed screenshots of bad dimension (diameter.JPG) and almost good looking half diameter (half-diameter-thickness.JPG). In the second one I used Note tool but I need constant thickness of line (0,35 mm) and I couldn't figure it out.

Btw I created 2D drawing from 3D model.

So how to create this dimension?

Sorry for my english.

Matt

SolidworksDrawings And Detailing