Hey! This thing is still a Work in Progress. Files, instructions, and other stuff might change!

The UnLimbited Arm v2.1 - Alfie Edition

by Team_UnLimbited, published

The UnLimbited Arm v2.1 - Alfie Edition by Team_UnLimbited Jul 14, 2016

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***17/07/2017 - Receiving feedback that the pins are too long to insert in cuff tensioner box easily. The Cuff minimum has been reset to 65mm to fix.

***14/03/2017 - Update v2.1 Rounded cuff edges, refined palm. Version / Measurement A B C / Hand scale% now stamped on underneath of cuff for reference.

Team UnLimibited are very proud to release version 2.0 of their UnLimbited arm design; named the Alfie Edition after it's first recipient.

The UnLimbited Arm 2.0 is fully parametric and customisable using Thingiverse Customiser to produce all the files correctly scaled based on a recipients real world measurements.

This is the next generation deviced based upon the popular 1.7 Isabella edition that was released last year as found here :- http://www.teamunlimbited.org/the-unlimbited-arm/

Please check out our Blog and Facebook page, be sure to like us and follow our work.
If you want to help us then please consider making a donation.

Blog :- http://www.teamunlimbited.org/

Facebook :- https://www.facebook.com/teamunlimbited/

Donation :- https://secure.squarespace.com/commerce/donate?donatePageId=55c484fae4b0a45eb98717b7

We would like to give a BIG thank you to the following people for their advice and help on this release.

Steve wood AKA Gyrobot for his ongoing support - http://www.gyrobot.co.uk/
Tony Buser from Thingiverse for his advice on customiser.
Jen Own from Enabling The Future for her continued effort to blog the activities of the e-NABLE community - http://www.enablingthefuture.org/

We also like to thank the e-NABLE community and Everyone else who has helped support us over the last year so we can keep giving the world a helping hand; or arm in this case !

For more information on e-NABLE visit http://www.enablingthefuture.org/
To get involved with the e-NABLE community please visit https://plus.google.com/communities/102497715636887179986

Print Settings


BQ hephestos 2 / Wanhao 4S






.2mm Layer height


35% Honeycomb


We print using Simplify3D,

The Palm Area and the Cuff need support when printing; NONE of the other parts do.

For the Palm we typically add 2/3 rows of support in the middle of the palm area to help with bridging.

For the cuff we use auto generated support.

ALL parts are printed in PLA to allow for easy thermo-forming.

We suggest the following additional print settings :-

3 Perimeter shells, 3 Top and 3 Bottom Layers.



The Unlimbited Arm V2.0 - Alfie Edition is the successor to the previous Isabella Edition arm released by Team UnLimbited last year.

Key Features :-

  • Arm is now 100% Parametric and can be scaled to ANY recipient size, with only constraint now being print plate size (were working on fixing that as well)

  • Using real world recipient measurements Thingiverse customiser will generate ALL required components pre-scaled to recipients size.

  • Massively simplified workflow to build an arm.

1 - Measure recipient
2 - Use Customiser
3 - Download components
4 - Print
5 - Assemble
6 - e-NABLE the Future !

Taking Recipient Measurements

In order to build and UnLimibited Arm the following measurements are required.

  • The length of the NON-AFFECTED hand as measured from the wrist to the end of the longest finger. Shown in the Diagram as measurement C.

  • The length of the NON-AFFECTED forarm as measured from the inside fold of the elbow to the wrist. Shown in the Diagram as measurement B.

  • The circumference of the AFFECTED upper arm, measured from the middle of the upper arm; Shown in the Diagram as measurement A. TAKE NOTE thats the AFFECTED arm you are building a device for not the NON-AFFECTED arm the other measurements are taken from.

Using Customizer

Now that you have the measurements for the device you need use customiser (from the button on the right of this page)

Enter the measurements into customiser using the drop down box and the slide bars and click Create Thing.

Once processes in "My Things" section you will be able to access and download all the files you need for your generated UnLimbited Arm.

N.B. If previewing the Phoenix hand elements of the arm you will not see these scale in the preview box, but trust us the end files will be re-scaled as per your measurements.


Assembly of the arm is the same process as that of the 1.7 Isabella edition, using thermo-forming. This has been previously covered in our 1.7 video and is provided below.

UnLimbited arm Tendon Stringing Instructions (10 Mins)

Why We Do This

Below is a video showing why we do this, using 3D printing to bring smiles to those with a limb difference.

Why others do it

Please see a video about a 10 year old boy called Henio from Poland his arm was produced by Krzysztof Grandys who created this arm using this thingiverse design and customiser.

Contact / Feedback

For any feedback or to contact us please use :- [email protected]

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Ive just seen this on amazing spaces sheds and it brought a tear to my eye! Everyday im amazed at what this technology can achieve, but this eclipses EVERYTHING ive seen! Well done to are a true hero.

I have read through a bunch of comments and appear to be the same situation in regards to printing for smaller children.

A - 152
B - 140
C - 102

Any suggestions on what to do there?

If the measurements are too small then wait until the child grows !

Amazing work. I will join this cause, and reach out as well :)

U guys are awesome!

Hi, I was wondering if you can provide advise. I'm thinking of getting 3D Printer model: Prusa I3 DIY DESKTOP PRINTER for making the unlimbitedArm. Would you recommend this 3d printer? thanks

This looks amazing I am so in awe of your dedication.
I have 2 da Vinci 1.0 and a soon to be crt 10
I will be honored to join your cause and I will offer this print around the U.K. For you as well
My email [email protected]
Would love to talk more

Hello, my software is Repetier-Host and it is giving error in some pieces like the palm of the hand, what I do?

but can i have the robot hand if i still have my limbs?

Hi, i was wondering if you could release a model without the need of thermoforming, we plan to do a lot of these and it would be easier if we had the stl models already bend.

The purpose of printing flat and then forming to shape is to reduce printing time (dramatically) and keep costs down. It is also extremely strong also. Forming the parts is not difficult, we have built many in batches also. the included jigs help with this.

We are being asked for help with a 15 year old double amputee. I love the look and design of the Unlimbited hand and the Customizer program is a great innovation. So respect to all those that worked on the development. Great job!

My first concern with our case is the measurements - since she is a double amputee, we'll have to estimate the Customizer parameters. It seems to me that we could base the lengths of the forearm, hand and cuff from her upper arm length. I'm wondering if the forearms could be made shorter than the norm, in order to be more stable and therefore easier to use. Does anyone have suggestions on this?

Tom - e-Nable Caribbean

You might want to use a child with a similar size to use as reference.

Hi there

I have a case A:13,5cm B: 15,5 cm C: 11,8 cm
When I enter customizer I am limited to enter A:16.00 cm B:15,5 cm C:13,5 cm
is it all right to do so or should I try something else?

Best regards
Serdar - Robotel

Which measurement is the problem. Forearm length?

I have exactly the same issue as baykush.
I need to make a prothesis arm for a 5 years old girl.
But in the Customiser Software, limits are too high for my needs.
Can you tell me how I can have STL files for my needed size :
. Hand Len : 115 mm (C)
. Forearm Len : 155 mm (B)
. Bicep Circum : 145 mm (A)
(In my case I can't set the hand and biceps len in the Customizer Software).

Best Regards
Greg - e-Nable France

Jul 30, 2017 - Modified Jul 30, 2017

If a kid in Cincinnati, OH needs one of these, I'd love to print one for them. Message me here or at mike at jesuspainter dot com if I don't see the thingiverse notification.

Hi, we print this hand for a 7 year old Portuguese boy. Our printer gets problems when it comes to the pins and the finger tips and always masses one or two up. So we want to separate the combined objects in single files so that we can print them separately. Is it possible? In Fusion 360 we were not able to do so. Thanks

Hey, I had the same problem with the fingers. My problem actually originated from having faults in the stl's. I downloaded a free program from Autodesk called Netfabb to fix the stl's. It also let's you change other things, and I believe you could separate the parts with it.

You've probably already fixed this problem, so I'm just putting this out here for anyone else :D

Hi all i'm trying to build this one for my son for the first time. can someone please confirm apart from all the 3d parts mentioned here, do I need to also buy Phoenix Hand by e-NABLE Assembly Materials Kit? or does this printed parts already included everything to build The UnLimbited Arm v2.1 - Alfie Edition? Thanks

Hi; This will supply you with all the stl's to print a full arm and hand. The only extra materials you will need are:

Dental elastics for fingers. We use Mauve!

100lb 0.55mm Dyneema (Uncoated) for the tendons.

3 m3 x 20mm hex bolts for the tensioner pins/box


Hi All, my son is a high-level quadriplegic, meaning no control of his wrists or hands. Has anyone ever combined the wrist driven models that accept hands with this elbow driven model? A product like that would give 100,000's of quads a way to bring back grip that did not involve risky expensive and often unsuccessful surgery. (We are actively trying to decide which of these undesirable options to pursue for him and then I came across this site.) I'll keep this short and happy to answer any questions. He CAN bend his elbows (as most high-level quads can). GREATLY appreciate anyone's help, advice, pointing me in the right direction, whatever comes to your mind.

Thanks - Dave Sternberg (jessesrecovery dotcom if you want to see who you'd be helping)

AFAIK i believe yes it grips based on elbow flexion, but I'm still working on my first one to make sure it can

Hello! trying to make this so I can see If my printer can reliably print these for charity, but one issue is that the STL for the fingers, especially the thumb one, has a gap in it, and I'm afraid of trying to print with this.

I have tried using prusacontrol and prusa slic3r and both seem to have the gap, along with making a new customization file leaves a gap too. any ideas?

I had the exact same problem, took me forever to figure out what was wrong. I fixed the stl's with Netfabb.

The fingers print fine without any support.

The forearm is too big to print, how do I split it into two parts?

I see from your video that you've recommended 20mm/ 4.0 oz, or 30mm/ 5.5 oz dental bands, and 0.55mm 100lb Dyneema braided fishing line.

Can you recommend specs for velcro straps and elbow pins? Anything else I'm missing, or is there a bill of materials somewhere already that I can refer to?

My machine uses .stl and i bet lots of others use different . as well so if you could add some that would be great!

i think what you mean is that your 3d printer uses stl files, right? because every printer uses gcode, thats basically the entire stl cut in layers and then converted to code that the printer understands, so there should be no problem with unlimbited just uploading stl files

Click the customiser button, and then specify measurements. It will then generate all the stl files necessary!!


First, CONGRATULATIONS! This design is perfect and my team and I are going to give one to a little fellow.
We are still printing and we came up with one question.
When printing the palm, you suggest to choose: "For the Palm we typically add 2/3 rows of support in the middle of the palm area to help with bridging.”
We have a Makerbot Replicator 2X, I am sorry, if my question is too stupid, but how we can define the number of rows of support on our machine settings?


it just depends on the slicer you use, some let you customize it and some dont, craftware is a very good slicer that lets you custom place the support and its for free

Hi there

we measured 130mm Bicep Circumference in a case and limit is 160 mm. can we change that?

I have thought about trying to print components or assemblies of children's prosthetics. Is there a good organization to contact for placing "orders," and would something like this qualify as a charitable donation for tax purposes?

You should contact e-NABLE. They 3D print and distribute prosthetic hands and arms. You can sign up with them to start printing and they will distribute your prints around the world. No idea about the donation bit.

Apr 26, 2017 - Modified Apr 26, 2017

Awesome Idea! design.

How long does it take to print all of the materials? Thanks!

Love. Inspirational. I have an idea. I'm not good enough at designing with software to pull something like this off, so maybe if your up to it? One of my best friends had a stroke at 22 paralyzing her entire left arm. I've been improving cone designs based off ones given to her in therapy that open her hand as it tries to clench shut. This resistance over the last few months has actually got her hand to stay slightly open for the first time in 8 years. I'm trying to wrap my head around how to make this hand support her hand that doesn't want to work so we can force it to get normal movement whether it wants to or not. She's getting married in the fall, and my goal is to get her hand open so she can wear her ring. This type of parlyzation is common for people that have had strokes. I'm convinced that if we can get her hand to mimic its old movements her brain will be able to mend the connections seeing as just resistance alone is starting to open it up. Any ideas?

It wont give me the file.what should I do?

We are building the arm for our MESA competition and we are having a problem with the forearm, jig, hand, and cuff. They all have different widths. Is there a way to fix this in the customizer?

thanks for you reply

Currently working with one of my students to print this for her. She is really excited about it, and so is the administration of my school. Just used the customization app and waiting for it to finish. Can't wait to help this person out!!!!

Good luck! we wish you well. Let us know how it goes!

Will do, the student picked out her color scheme yesterday, glow in the dark blue and florescent pink. The fingers are finishing up now.

i can not find the finghers,,, :(

v2.1 looks great! It would also appear that you've simplified and standardized the strap slots - excellent news.

i need to print an arm for a french girl
his hand len is 110 mm how can i rescale the files ,the less value of the customizer is 135,i use it?
thanks and sorry for my english!

The minimum is set to 135mm which equates to 100% scale. Any smaller and the pins would be too fragile. I would recommend deducting the difference from the forearm if possible.

Thanks- another problem- the mesh for the palm broke so we need to reprint it - we've already connected and strung the palm and everything is done, so we can't just print the palm file with the mesh attached because we can't replace the palm on our arm. Any suggestions for how to scale the mesh? We have the mesh as a file alone from the Phoenix hand? Or is there a way to 'cut away' the palm from the mesh and attach it?

To calculate the print scale, using the "Hand Len" measurement originally entered into Customizer:

(Hand Len / 135) * 100

We downloaded the files and printed all the parts, but the 3 pins that the tendons string into up at the top of the arm are not included in the file- can someone post the .stl for those pins? Where are you guys printing those 3 pins?

The tension pins are usually included with the cuff.

Hello, we are 3d makers from India and have tried printing this arm successfully. The only thing we are stuck with is the movement of the fingers. We are able to bend the finger from the center, but not from where the finger begins. This makes it difficult to size the objects. Look forward for your guidance on the same.

Sounds like your tolerances are off, check your printer calibration and measure your parts, they is enough space between the hand components for them to move freely.

Thanks for your reply. The fingers move properly with a manual action, but when we try to move the fingers using the strings only the upper half is able to bend and the lower half stays as it is. That is where we have the problem.

Hallo, how much cost the production of this arm if I had access to a 3-D printer. Can I rebuild this arm so that it works for people without an elbow????
Thanks for helping :)

Currently this arm is elbow powered, you could always re-develop it to work for users without an elbow and use a shoulder harness, this is something we have yet to investigate.

Hello, thanks for your fast answer.
Is it possible to communicate with you via social networks or e-mail.
We have a few question about printing this arm.
Lg Dominik Ballwein

Do you have any suggestions for printing the large parts using KISSlicer?

Nope, never used that but use the same basic settings for perimeters and infill etc.

I offered to print this for free for some one that need it, and one lady askme if i can print for her one, of coure i can...
I down load the file and is an scad file tha i dont know how to use it, please help me i know how to use the stl file but nothing about the s cad
Some one in Dybai will thank to you

Scroll down, read the instructions and click customiser !

Sep 19, 2016 - Modified Sep 19, 2016

hi when you used slicer the file are broken
look the circle
how fix it?

That is down to your slicer settings, I have seen that before with other parts. Reduce your extrusion width.

the stl are broken you can fix it?
look the circle missing one part on midle

The diameter of the bolt hole that you have specified is too large for the tension block. Please choose a smaller diameter.

Sep 6, 2016 - Modified Sep 6, 2016


I am printing one of these for a local 11 year old and I guess the hand is separate so looked and there are 2 versions of the Phoenix hand will both work with this arm?

Also the Arm is customizable using the app so that it's the right size but the hand seems not, is this correct or am I missing something here.



Nope if you use customiser you get ALL The parts including the hand scaled to the correct size.

All files needed are generated correct to scale, and contained within the zip after you've entered the measurements in customiser. This zip contains the recommended thermo palm Phoenix.

Aug 31, 2016 - Modified Aug 31, 2016

Hello Team

We have Prusa i3 with mirror size 20x20 cm.
From your experience, will it be sufficient to print the longest part (forearm) ? I don't know the length of this part for a 6 to 8 years kid.

If not, are you planning to create a code for a split forearm into 2 parts, that could be assembled and securely tightened ?

Looking into your Openscad code, it is not so easy for me to figure out where to cut the part.

Thanks your your wise comment.

It's on the to-do list !

This is amazing, thanks for taking the time and putting your efforts into this project.

Hi Im In Merida Mexico. Im a 3d printer and i will be glad to print one of this for free for some one that need it... my e mail is [email protected]

Do you have STEP file?

The version of our arm is fully parametric and generated purely from code in OpenSCAD, they are no STEP or IGES files.

for the infill settings, i dont see a honeycomb option. im using makerbot software, and they have.

Any infill should be fine TBH.

Recently completed and delivered version 1.7 arm to recipient; great design. Several questions related to version 2.0: (1) Are there any plans to have the v2 Customizer produce a scale factor (e.g., 95% or 0.95) for the files generated after the recipient's measurements have been entered; (2) Used the Customizer for a recipient all except one of whose measurements were below the minimums on the sliders. Could such a situation be considered to be 100% (1.00) scale?

This iteration of the design does not work from scaling but real world recipient measurements.

We do not advise making the device if the recipient requires it below 100% as typically they will be to young.

is there a specific type of filament that make the pieces bend. My makerbot has PLA filament!

PLA is the recommended material.

This is fantastic work, fellas. I'd be curious to see what the long term survivability is. I like the idea that you can replace a broken finger or elbow joint in a few hours.

Hmmmm. Wonder if you can get flesh colored filament?

We have used flesh colored filament, we have also had recipients who have returned after a year who only need bands replacing, or new elbow pins. So survivability is really good. Although re-printing a part is inexpensive and quick ;)

I love that you built the whole design into OpenSCAD. We tried that with Hand-o-matic but, at the time, the STL files converted into OpenSCAD were too large for Customizer to run. What did you model those parts (palm, fingers) in?

Some triangle reduction and secret sauce and all the phenix parts, including our thermo-mesh palm are converted directly from STL ;-)

Dear Sir,
the file you uploaded is a SCAD file, can i ask how to change into stl file? thanks:)
Sincerely Gabriel

Click the Customiser button, it will generate the STL's to the desired size.

Dear Sir,
the file you uploaded is a SCAD file, can i ask how to change into stl file? thanks:)
Sincerely Gabriel

Click the Customiser button, it will generate the STL's to the desired size.

First of all THANKS for your great work... I am planning on printing one for my wife. She has an elbow but very small forearm, I dont know if she will be able to lift the prosthesis. Is there a way to make the elbow hinges lock in a couple of different places so that the wearer can preposition the forearm with the other hand? May be if the hinges have teeth that lock every 10 or 20 degrees.

I have found the following, just as ideas:

something like the following, but since the material is plastic it might not need the lever

Please let me know what you think or if you have any solution.


You can use the mounting holes on the forearm to try to strap the device in place, short residuals are a very big challenge and indeed even professional prosthetic companies struggle with short residuals.

All I can suggest you do is try and you could post your findings onto the e-NABLE google plus community to see if anyone can help.

Community is here :- https://plus.google.com/communities/102497715636887179986

This thing that you make is incredible.... Had no words to describe how big are your hearts... I swear that I would be like you in future. You have a new idol.

Hi, how would convert the files to STL files and be able to print on a makerbot printer, >??? thank you

As per the instructions use the customiser to enter sizing data then click create, it will then generate the STL's

awesome thanks, just complete it. Now once i have it in makerbot, there is no need to scale anything right?

is the makerbot material able to bend as well

Hi Team
Can you provide 3D STEP or IGES assembly part files of The UnLimbited Arm v2.0 for us to study in Taiwan, We Team want to help for this. thanks..

The arm is fully parametric and scripted in OpenSCAD, they are no STEP or IGES files, you could however generate an arm as STL's then convert / redraw if thats what you require.

Such an incredible design and cause. Great work!

Out of curiosity - what is the white disk on the top of the hand for exactly?

The white disk (in the photo) is an eye. The 10 year old recipient requested a "Minions" themed arm.

Comments deleted.

I know that you are different teams working in parallel projects, but I have seen the issues reported with the lifespan of the elastic bands on the Phoenix hand, has any thought been given to using your brilliant arm components with the flexy hand 2?

This has been discussed and we know Gyrobot (the creator of the Flexy-Hand) very well - he advised on some of this release.

I'm sure one day we will release a modded forearm to fit a flexy-hand.
From our own experience the bands last quite well and a £2 bag will last a year(ish)

Using thermoforming is a stroke of genius. Thank you for releasing this excellent work to the public.

Do users have any problems with chafing? I wonder if some kind of padding attached with velcro would be appropriate.

We always advise users to wear a prosthetic sock or a cotton sock over their residual limb.

We also tend to line the arm sections with this for extra comfort - https://www.amazon.co.uk/Dr-Scholls-Moleskin-Plus-Padding/dp/B0013T825C

Extra padding can be used and medical grade padding is available online.

This is my first ever comment on Thingiverse, and I just wanted to say that this is the most inspiring thing I have seen in a long time!!!

Now I wish I bought a printer with a bigger printbed!

Keep up the great work!!!

Thanks :-)

Jul 19, 2016 - Modified Jul 19, 2016

Hi , im in the Montreal area, I have a few printers and could print and donate. to whom or where should I contact ?

and could you provide stl version please.

Jul 19, 2016 - Modified Jul 20, 2016
Team_UnLimbited - in reply to tibuck

Hi start with joining the community, you might find someone local to help !


To get the STL's use customiser, enter the size you need and it will then generate the STL's

Cool. Amazing work guys

Jul 19, 2016 - Modified Jul 19, 2016

This is the best that I have seen at #thingiverse.com

Thanks, we think so as well :-)

the customiser scale all files of the unlimbited arm to the input measurements?

Yes, all the parts are scaled to the measurements you provide, to give you a full arm.

Jul 18, 2016 - Modified Jul 18, 2016

Regarding the type of plastic used for the arm, I am not familiar with the thermoforming technique. Will ABS plastic mold this way under the effect of hot water? I'd appreciate any advice. Thanks, and I do really admire the work put behind this design!

Hi. Only PLA is recommended for this application because of it's relatively low forming temperature.

hi i need help with your new model. I saw the video of thermoformed but I have no tutorial that shows how the threads are tied hand and fits thank you very much

hola necesito ayuda con su modelo nuevo. vi el video del termoformado pero no tengo ningun tutorial que muestre como se atan los hilos y se ajusta la mano muchas gracias

Video tutorial for stringing the tendon lines is now available. https://www.youtube.com/watch?v=nIHpqqgybss

thnz so much
do you have tutorial for this model http://www.thingiverse.com/thing:1131463 ?
and thnz again

Arm v2

Sorry no, this is not our design.

Hi we are working on more instructions, to get more advice join the e-NABLE global community