Comes to mind FreeCAD, Qcad(there's a windows build) free version , VectorEngineer (the free version), cadstd lite (I think was so called)...
I can't put links here, at least, not several (yet). But probably are easy to find with Google.
Anyway, those above, if you want to go further of what the free versions (are free, not trial) offer, are in the rank of 30 to 50$, no huge deal...
But I don't know if any will exactly fit your needs. (I've done and sort of teached technical drawing, I think I know what you need, but..)
There was some effort in making a module/plugin for Blender, to use it for cad purposes, dunno how is that now...
Who knows! Even Google's Sketchup may be helpful in part of the proccess...