Could anyone modify an stl file for me?

If you have Slic3r & Reptier, you can follow these steps

  1. Slic3r:
    A. Open STL
    B. Rotate STL
    C. Cut STL (you need to do it two times)
    D. Stretch that require portion (as it is not having complex geometry, it shall work)
    E. Save individual parts as STL
  2. Start Repetier host
    A load all three component
    B. Place them. I use to edit X/Y/Z manually in terms of 3 decimal accuracy
    C. Save it as STL

And if require, repair it using netfab.

I just edited NASA wrench and shortened the handle and added a PIN in similar way.

There is a web site that converts an STL into Openscad. Check on http://www.thingiverse.com/thing:62666. The result is not really user friendly, but this can help in some cases.

If you have not yet been able to complete this task, I will be happy to make the modification you need and send the updated version back to you, just message me on gchat!

If you still need it done, let me know. My CAD software can handle that in .stl and a good bit more. So no problem in adding to that arm.

ill help but if you want ill tell you what to do in freecad to do it. good start to figuring out how to do thing like this.

Thats all done, thanks again for all the help