Artistic visions for prosthetic design XXII - Red Hand 2017/I - communicative hand design fitting onto standard Alpha gel liner / Ossur pin with flexible yet reliable comfortable attachment [boosting appearance hand/ boosting wearability in 3D hands]

#userdrivendesign #bettercyborg #3dprint

The development of an office/presentation hand that is both extremely light and effective as communication tool - rather than the hitherto entrenched exasperated display of ill fated gadgetism with too much dead weight - requires a few tricks. So it is understandable that industry, research and the "open prosthetics" scene has not picked up on it.

So far, "bionic" hand gadgetism has banked upon the fact that still images, photos, posters and derived advertising materials are stunning, and their actual proficiency tests are never longer than some 10 minutes. No bare arm stump survives a 3d printed socket as such though for any serious 8 or 10 hours, and suspension remains problematic, particularly for the self made / open prosthetics scene. That aside, prosthetic hands can still very safely be classified into those that may be used for social or very light use (alliterated as "work", "sports") and those that are really used in a way I find normal but that prosthetists will say is "extreme" (i.e., proper work, or proper sports, as in "real" life usage).

Of course, it is also clear why people keep proposing their same old paradigms over and over: they do not have any different. There does not magically occur any different. There is a reason why they still propagate the Russian arm design. There is no other alternative easy to just grasp and copy, and no one paved a new way. It is paving a new way that seems to be so hard.

And things do not change by themselves, don't ever believe that.

Only after I had introduced, personally, a few key users and the general public to the "red hand" back in 2009, did we see new occurrences of red or otherwise non-biologically colored hands, mostly without reference to my original.

Color, however, is only one aspect of introducing progression, evolution, advancement to prosthetic hands, grippers, arms.

We still have not seen any actually non-hand shaped grippers being "cool" or "promoted" under the new "bionic hype", which remains weird, seeing as if "transhumanism" and "Cyborg" movements both pretend to promote alternate or non-anthropomorphic appearances as equally acceptable. I mean, that is what they say: non-anthropomorphic (as in "having wings") is what they want to get accepted. But do they? Aren't they really some mentally understaffed individuals that just want like their Modafinil legalized for wide daily use but that otherwise are just as conventional and old fashioned as can ever be? The ways they seem to go about "modernizing" aspects of arm amputation certainly makes one believe so. And so for yet to be uncovered but relevant reasons, they keep hacking on that same old anthropomorphic hand with unprecedented stubbornness. As far as I am concerned, they should start that exercise (that of embracing Cyborg or transhumanism concepts with non-anthropomorphic bodies being cool or at the very least acceptable) with accepting my hosed arm as is, just too see with how much non-anthropological shape acceptance we can get from the self proclaimed futurists already today - ... which is probably still a long road to travel until we get there. Then after they may have accepted that, maybe in the year 2090 or so (wild guess), another 150 years will probably go by until they actually understand, and accept, the brutal genius of prosthetic body powered hooks. Today it is the choice of the extremely intelligent - not of the intellectual, not of the reactionary conventionalists, no, but of the actually extremely intelligent.

So, maybe by the year 2200 humanity will have caught up, hopefully.

Until then, I am sure you agree that we all have more than plenty of time. I mean, we literally bathe in time before anyone would be forced to actually act on the requirement to "step up" or "modernize".

That leaves the actual pushing forward of prosthetic arm developments and concept to us, the users. That is not at all new either.

As I do not plan to wait until 2020, I now introduce "the cheap mechanical pin lock". See the following images.

Red Hand 2017/I


The hand has both a socket and a hole : ) As you can see.

3D print wise, nothing fancy yet, PLA, 10% infill, all red, single print with a Makerbot.

The arm with liner (and attached pin) can be pushed in comfortably. Snugly, even. I made it so ; ) No 3D scan. Just good old engineering. To know what one is doing ; ) (disclaimer: I have alginat, cast materials, and a 3D scanner, just saying) (but no need for a socket) (not what you were thinking, I know) (I KNOW #rollingeyes).

The big hole of the hand and the pin hole meet : ) so the pin will protrude.

I actually planned for that.

The pin is supposed to do that.

Didn't I tell you so? The pin protrudes.

The insert for the big hand hole? Yeah. That has a cut out that secures the pin.

Just shove it in.

It works absolutely beautifully.

That hand does not go anywhere now any more.

And it looks fabulous as is - before I even started with tinkering with more detailed surface aspects that I plan to add or so.

It cannot fall off as it is totally secured into place : )

The pin does not have to go in all the way to lock.

That is as pins usually work. And this one totally works even though it is the first prototype that I made, like, ever. Yoo hoo.

The hand plus lock and socket, totally, weighs 184 grams. That is why it is so extremely nice, also for typing.

Research and development aspects

I designed a first socket that would fit my "stump plus liner" (didn't even need to use the 3D scanner for that) and then I reduced it to a very short socket as to allow for wiggle and swinging, to approximate Becky Pilditch and Holly Franklin's "gestural hand series" (LINK) who first came up with that and who also provided first research and testing into a sensible impedance.

Correctly cite this development for your paper:

  • Becky Pilditch and Holly Franklin (2010) Super Prosthetics Project - Gestural Hand Series
  • Wolf Schweitzer (2017) Red Hand 2017/I


  • With this I can wear a regular comfortable liner and, design wise, plug it into any of my 3D fun I am having.
  • This concept is able to boost 3D printed hands into the realm of the comfortably wearable.Realistic or at least a relaxing to watch dynamic - rather than static - appeal requires lax joints and lax connectors.
  • Comfortable wearing of a prosthetic limb requires a closely fitting suspension.
  • Pin locks are standardized items and with that approach you may be able to also standardize connecting sockets to hands.
  • Always remember that you want to break components down into a modular setup to increase sales- get your prosthetist or 3D scanning guy or so to provide a socket, and have that interface with the hand.

First usage aspects

Remember this is a first alpha version. Designed, printed and slapped on. No practice, and revision cycles only starting now.

Explaining stuff

Reading a book, holding pages

Reading books is totally cool as well. With just a few more modifications this is a very promising "hang out hand".




Next steps

Sure, I gas everyone's head full about how important suspension is also for 3D printed hands and everyone tells me, well hell it is a problem but we cannot solve it, until the very moment I go and just do it. So from this moment on, you CAN officially mount 3D printed hands and arms on pin bearing liners. Just allow yourself to do that. Super comfortable this is.

With this here, I addressed an aspect I had in mind since writing the appearance test / SHAP review article and also when reading about the ZHAW project.You want perfect suspension on the stump particularly when the user is sweating - as in: sports, activities, warm countries.

With a 3D printer available and other technologies, this now can be built and demonstrated by me as there is no better and more convincing way than to "just do it". I have a number of other funny ideas to put on the road, so bear with me ; ) Now it cannot be undone : ) Cool, right.

But there are unsettling aspects here. Why does it always have to come that far? Why do industries, open prosthetics engineers and academics always let it come that far that at the end of the day, an arm amputee paves the way into the future? Don't you have like  pride in you? Why aren't you better than that? Don't wait for me to do your work! Do it yourself and do it better than me! And do it before I manage to get around to it! Please.

The next thing you all may want to build is a body powered hand that looks really really good. Just telling you that that is what you want to build. And it connects to standard ball cables and 1/2-20 threads or so and it will be published on Thingiverse or so, with STLs for everyone to play with : ) And the standard for body powered adaptive / precision grip hands has been set to extremely high with the Becker hand, and with the Monestier hand. Both are marvelous and extremely refined designs to start with.

Cite this article:
Wolf Schweitzer: Technical Below Elbow Amputee Issues - Artistic visions for prosthetic design XXII - Red Hand 2017/I - communicative hand design fitting onto standard Alpha gel liner / Ossur pin with flexible yet reliable comfortable attachment [boosting appearance hand/ boosting wearability in 3D hands]; published 19/02/2017, 15:00; URL:

BibTeX: @MISC{schweitzer_wolf_1604183729, author = {Wolf Schweitzer}, title = {{Technical Below Elbow Amputee Issues - Artistic visions for prosthetic design XXII - Red Hand 2017/I - communicative hand design fitting onto standard Alpha gel liner / Ossur pin with flexible yet reliable comfortable attachment [boosting appearance hand/ boosting wearability in 3D hands]}}, month = {February},year = {2017}, url = {}}