IMPORTANT SERVO HORN UPDATE
2017-08-31: As it turned out, the vendor on eBay selling the double-sided servo horns for the grippers is out of them. In response to this development, we have redesigned the gripper to allow it to be used with the standard single-sided horn that comes with the DS3218 servo. The new model has just been added to the list under the name rcr_gripper2.stl. We will complete the stress-testing of this new design by tomorrow end-of-business, Sep 1, 2017. Also the eBay vendor has promised to restock the double-sided horn in 2 weeks or less. One way or another, please rest assured the horn problem will be resolved.