About Model T42

The Model T42 is a more dexterous alternative to the Model T. It consists of two underactuated fingers with compliant flexure joints, each driven by an independent Dynamixel actuator.

Flexure joints are made through Dieless Deposition Manufacturing (DDM), utilizing Smooth-on polyurethane. Tendon-driven, flexure-based joints allow for adaptive behavior and robustness against collisions.

The estimated fabrication cost is $400-700:

  • 3D printed parts (~$250-300 depending on vendor)
  • urethane materials (~$50)
  • Dynamixel actuators (~$400)
  • fasteners (~$50)

Lael U. Odhner, Raymond R. Ma, and Aaron M. Dollar
"Open-Loop Precision Grasping with Underactuated Hands Inspired by a Human Manipulation Strategy," IEEE Transactions on Automation Science and Engineering, 2013 (in press)



  • Actuators: Dynamixel RX-28 (x2)
  • Base height: 55-80 mm
  • Base width: 100 mm
  • Weight: 350 g


Build - Model T42


  • Ver 0.3.2 (11/28/13) [.rar] [.zip]

  • Ver 0.3 (6/2/13) [.rar] [.zip]
  • In Progress: Ver 0.4 (Tactile sensor integration)