Talon Hand 2.0 (now 2.7)
by profbink, published
This is a remix of Makerbot's snap pin robohand. Thanks go out to the designers of the "Complete Set of Mechanical Anatomically Driven Fingers", Ivan Owen of Mech Madness Designs http://mechmadnessdesigns.com/ ; Richard Van As of Robohand http://robohand.net/ ; Michael Curry, the designer of the Snap-Together Robohand ; and to all the collaborators at e-NABLE https://www.facebook.com/enableorganization
I've optimized the design to be more ergonomic/comfortable, and to use leather as an interface material. With 3 pieces of leather you can mount this prosthetic device to a person lacking fingers on one hand.
Two sets of fingers are included: One with snap pins and one for Chicago screws.
Here's a clip of my son Peregrine putting on his Talon 2.2:
And here's he is playing at home:
After upgrading to 2.7, and some 2.0mm monofilament cables:
For more information or to get involved, visit http://enablingthefuture.org/
Now available here is a wide unipalm and matching wide cable guide. Thanks for the great mod, Ivan Owen!
***Significant upgrade on Feb 5, 2015!! Please provide feedback on the new files, and contact me if you need old files. There is now a cable anchor that takes 10 set screws, two for each cable, to prevent cable slipping, and the cable guide now has a left and right version, and better guides the cables, so that monofilament can push as well as pull, therefore obviating the use of elastics. :D
You can print everything but the finger distals with no support.
Ivan Owen has published an excellent step-by-step tutorial, in 3 parts:
Thank you Ivan!!
I'm working on detailed written instructions for all my wrist-powered devices at:
The cable anchor for the Talon Hand uses set screws. I used heavy gauge nylon monofilament, which is available as fishing line or round trimmer/weed whacker line (like for landscaping) for the cables, and found that if I mount the anchor forward and close to the cable guide, the hand will open without elastics. The cables push and pull.
Here is the hardware list for a build at the scale of 100%, a good size for a 4-5 year old child.
wrist hinge: (2) 8-32 x 5/8" flat head hex screw; (2) 8-32 nylock nut
Anchor mount: (3) 3m x .5 x 8mm flat socket cap screw; (3) 3m x .5 cap nut
Cable anchor (5) set screws 6-32 x 1/4
Cable guide: (4) truss head sheet metal screws #4 x 5/8
Palm leather tacks: (16-20) truss head sheet metal screws #4 x 3/8
Leather to arm bars: (8) 6-32 x 3/8" flat socket cap screw
- a layer of 1" nylon webbing: (1) 6-32 x 7/16" flat socket cap screw
- 2 layers of 1" nylon webbing: (1) 6-32 x 1/2" flat socket cap screw
5 pieces, each ~a foot long 1.2mm or 0.05" round monofilament for the cables. Fingertip ends of the line are melted into balls with a lighter so that they catch in the tips.
I typically build this for Peregrine, my adult son, at a scale of 160%. He has an extra-large right hand. Obviously, the hardware should be larger for his build. Here's a list of hardware:
Talon Hand at scale of 160%:
10 Arm Bar Screws #10/24 x 3/8 or slightly shorter flat socket cap screw
2 Wrist Hinge 1/4" x 3/4" and nylock nuts
20 Palm Tacks #6-32 x 1/2"
10 Set Screws #10-24 x 5/16"
4 Cable Guide Screws
Cable anchor: 3 flat socket cap screws and dome/acorn nuts
Nylon or Poly webbing for strap(s) and/or palm reinforcement.
You should have three pieces of leather: One very thick, (6-7oz) for the "sole" of the palm, one medium thickness (4-5oz) for the upper of the palm and another medium thickness for the bracer/gauntlet.
You can make a closure with Velcro or double D-rings. OdyBars are for a child's device and uses a single strap on the third hole. There is a space so the strap is comfortable between the plastic and leather. ArmBars are for an adult's device and use two straps. Loop the straps in holes 1 and 3.
If you print small, the spaces between the parts will be smaller, so more finishing is usually needed. If you print the device small (100-130%) use PPsnap4small instead of ProxPhalSnap (better for 140-160%)
Now there is a zip file containing Ivan Owen's wide palm Talon Hand. Thanks again Ivan!