Update 1 : New Palm Added with Changed Plug.
This is a prosthetic hand design, "Gripper Palm Remixed V.G3D" which uses Torsion Spring.
You can make use of Gripper palm with Spring for your own Use.
Gripper Thumb Terminal Device Originally made by Skip has been Remixed and worked out to improve functionality. As in the original design, O-ring is used which was failing when multiple actuations were made and it did not return to its original position as well.
We tried using multiple O-rings but it did not have enough strength to withstand.
So I along with my team decided to remix the functionality part. The design is great and more natural looking so it makes recipient easily adapt to it.
We modified the Thumb and the Palm, where we made space for using Torsion Stainless Steel Spring ( Wire:2mm diameter, Inner Diameter: 7mm) locally fabricated, also we used a piece of Mild Steel rod (4mm Diameter) to keep the spring at the place. This provided us with much better actuation and grabbing force.
Plug is also modified, Skip had made a separate plug that attaches to the gripper palm. In this Palm, he has used bolt thread that is standard for the region and can be attached to the prosthesis but we needed the palm to be used with 3D Printed forearm so attaching it to Forearm was increasing the Total Hand Length so to cater this we incorporated the Plug within the palm. We blended the plug with the palm and made it a single part.
See this video for details
Now using this Gripper Palm we can attach it to the modified forearm from the Unlimbited arm and made a Remixed version of the Unlimbited arm to be used for recipients with Below elbow Amputations.
I will share the forearm and cuff design soon so you can make the Remix version too. But till now you should use this Gripper Palm and give feedback on this.
For more information, you can visit
Spring Type: Torsion
Material: Stainless Steel Wire
Wire Diameter: 1.9 ~ 2.0 mm
Spring Inner Diameter: 6.8mm
It can be either printed on ABS or PET-G.
FOR ABS you should prepare bed very well and use Brim 15lines. Make sure you have closed enclosure to avoid cracks on the print.
Heated Bed is 100
FOR Pet-G use Brim lines 15 and use PEI surface and gluestick.
Heated Bed is 80
Skin Paint is used to make it more appealing