Summary

***Added 'better bell crank' and 'links only' stl's.

Based on Persona's really cool instructable:
http://www.instructables.com/id/Mechanical-Claw-Ring/

Something about this design really mesmerized me (watch the GIF on the instructable). So I imported it to Skecthup and used it as a template, tweaking in ways I thought the 3-d print would need it.

Instructions

Update: I added 2 stl's--a stronger bell crank, and one for the links only because they are delicate. My printer likes the new crank better, and the links file is in case one breaks.

All the pins for the links are made from 3mm filament with the ends melted a bit and then squished flat against a glass.

The round piece is to hold the bell crank in place, just glue it on (but check for fit first).

The pieces that print up between the jaws are printed upside down, they are meant to be flipped over and glued in place to hold the fulcrum of the claw pieces (see picture where the claw pieces attach to the main body).

Mine printed okay at .35 layers (.5 nozzle), with 20% fill, except that a couple pieces needed some light sanding to fit well with the other pieces.

With a 1mm brim, the link pieces print out stronger I think, I strongly recommend this.

Oh, one last thing. At first the mechanism was sticky and felt like it was hanging up. I doused the whole thing in cooking oil, and worked it through the joints, then washed all the oil off with dish soap and water, and it's great--works smoothly, and it's not oily.

Claw with bell crank