An Instructable wanted to know whether Autodesk 123D can create precise parts:
http://www.instructables.com/community/123D-Design-tutorial-for-technical-parts-with-accu/
It is possible, and the description here is the one that the author gave as an example (see the first few seconds of the video).
It may well be, that AutoDesk 123D has evolved in the couple of years since the Instructible was written.
The approach taken here, is to lay it out using sketches and then extrude the result. This seems pretty quick and easy for most parts. I'm sure that there are many other (better?) ways of achieving the same result.
Having given up on AutoDesk 123D myself for the same reason, I took another look and realised that it can produce the goods using this sort of technique. It will save the result in several file formats suitable for 3D Printing.
