Hi All.  Since we've been talking about 3-D printing and using
a CAD software to produce the part, I have a word of caution about
CAD software.  Here is how the software works.

When you make a part from a CAD system the drawing can be saved in
several formats.  This is called interchange.  Go find the command,
go to the menu at the top of the CAD drawing screen and look for "File".
Next click "Export" which allows you to select the format.

In order for the drawing file to be used by 3-D printer the drawing
file needs to be saved in the .stl format, which is Lithography.stl,
according to several articles on the 3-D printing.

Not all online CAD software will export this .stl format, e.g., Free
CAD and Smart CAD.  I downloaded these programs and did not see this
file format.  My Acad 2009 has this STL format.

Go do a search on their webpage and type .stl and you will see an
article about 3-D printing.

Lee Walker

 [ STL (STereoLithography) is a format native to the stereolithography
 [ CAD software created by 3D Systems.  Ref. http://www.3dsystems.com/ 
 [ https://en.wikipedia.org/wiki/STL_(file_format) 
 [ FreeCAD http://www.freecadweb.org/  AutoCAD http://www.autodesk.com/ 
 [ http://www.autodesk.com/products/autocad/free-trial 
 [ http://www.quickparts.3dsystems.com/rapid-parts-prototypes-c/?gclid=CPbfk9vgnNICFUMdgQodvKgOLA1 
 [ -- Robbie