I also say Sketchup. Unless this clip will be the only part. In that case, just go to MakeXYZ.com and find someone local who can make and print it and bring it to you to show you what you can do to improve it.

Note about Sketchup: One bug is the "tiny dimension" bug. To work around it, multiply all dimensions by 100 before starting, then when done, shrink it 100 times and export it (but don't save the shrinked version).