What I'm trying to do is create a robotic hand. I created the mesh and added the bones for the fingers (following CG Cookies' tutorial on rigging fingers), but didn't add a bone for the "arm" part of the mesh.

I've tried adding the bone (the arm bone is named Bone.020), created a vertex group with the same name, then weight painted the part it should move, but that didn't work. I have tried parenting the finger bones to the arm bone, but that didn't work. I don't know what else to do. Any help is greatly appreciated.

[![Object Data panel][3]][3]
View of the Object Data panel

[![Bone panel][4]][4]
View of the Bone panel

[![Bone Constraints panel][5]][5]
View of the Bone Constraints panel

[![Fingers are working properly][6]][6]
Showing the fingers are working properly

[![Rotating the arm does nothing][7]][7]
The problem - Rotating the arm doesn't pivot where the "elbow" would be

[![Example of weight paint that works with thumb][8]][8]
Example of weight paint that works with thumb

[![The weight paint area for the arm][9]][9]
The weight paint area for the arm and palm

[![Armature modifier][10]][10]
Armature modifier in the modifiers panel


  [3]: https://i.sstatic.net/ucOsD.jpg
  [4]: https://i.sstatic.net/oGNOh.jpg
  [5]: https://i.sstatic.net/mKg80.jpg
  [6]: https://i.sstatic.net/5Nf7I.jpg
  [7]: https://i.sstatic.net/68TKM.jpg
  [8]: https://i.sstatic.net/PpddU.jpg
  [9]: https://i.sstatic.net/OdsFC.jpg
  [10]: https://i.sstatic.net/N5a5Z.jpg