Picture of Thumb Prosthesis
This is a high durability, high functionality low cost prosthesis for those missing the distal phalange of the thumb. This creative method can be extended to replace the distal or distal and middle phalange of any finger. The process detailed below is the greatest technological advance in prosthetics since the introduction of modern plastics, and will spark a revolution in the prosthetics industry.
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Step 1: Models

Picture of Models
I have included two models (free of restriction, share with all of humanity). You can use either model, the claw model is of more utility and can apply greater force than than a natural nail. You can also generate your own models from scratch OR (the most realistic and best fitting) generate a 3D scanned model from a whole digit scan and applying a mirror function to the model.

Step 2: Measurements

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Compare digits to find the specific metrics for scaling your model.

Step 3: Measurements

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Measure residual digit.1.jpg
Measure the residual digit (Residuum). Accurate multiple measurements will allow for a greater custom fit.

Step 4: Measurements

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Accuracy in measurement is paramount as this prosthesis relies on mechanical fit rather than flexible suction (restricts blood flow and thus wear time) fit.

Step 5: Scale Model

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Adjust model to fit residuum metrics acquired above. This is accomplished with modeling software and scaling for length and diameter. Also one should scale areas radially along the vertical axis.

Step 6: Print

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PRINT. This prosthesis is most durable when printed in nylon. I suggest that one always use a human friendly plastic for anything contacting the skin. Taulman Nylon 645 is the best material that I found as it has superior strength and quality as well as meeting the EU's REACH standards for non toxicity. Currently there are no suitable FDA approved printing plastics, however that will soon change.

Step 7: Comparison

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Compare the printed prosthesis with existing whole digit.
pythonus8 months ago

you should make it in a position as if you were grabbing something, also there is a rubbish filament that could give you better grip . Just thoughts on how could you improve it , But nice work !

Makinwine1 year ago
While I am fortunate to not have a need I am absolutely thrilled and impressed in the way that you took control of such a tragedy and have the resolve to not only make it better for yourself but for anyone and everyone. My hat is off to you
kyinrunner1 year ago
I lost to the 1st joint of my left index finger, is there anyway to do this without access to the technology?
Xibalbawax (author)  kyinrunner1 year ago
Check my finger prosthesis at thingiverse, you can use this to make a model for your injury and then send it for printing
Xibalbawax (author)  kyinrunner1 year ago
Yes there is. The mechanical finger ring at offers a dynamic prosthetic device for your particular injury, however it has a much large cost. I have a new dynamic prosthetic designs that may work but it is not yet perfected. With this current design it is absolutely possible to make a prosthesis for replacing the distal phalange. You can create a design for your self and have it printed a 3D printing service like Shapeways, i.materialize or Sculpteo. I will endeavour to post another instructable regarding the creation of a finger prosthesis. I lost the first and second phalanges of my right index finger. In the process of designing a suitable finger prosthesis I have also found solutions for those missing the first phalange. I am wholly willing to help you with this, if you are willing to be a test subject and provide some feedback. Please be patient as this is a project under development.
nerd74731 year ago
so you were in the army; by your tattoo
wylekat1 year ago
You could turn the claw one into a stylus with some conductive threads and such...
Xibalbawax (author)  wylekat1 year ago
exactly, conductive paint perhaps
agis681 year ago
The grow of our intelligence has begun when we start use our thumbs. good job!
Xibalbawax (author)  agis681 year ago
Thanks, you are absolutely right the thumb is hugely important and perhaps one of the greatest features that defines humans.
What heat, speed, and other settings did you use to print taulman 645 on the replicator? I have the same material and a replicator 2.

I found this while looking for ideas on movement assistance, that is, fitting up parts that aid a weakened limb, not replace part of a damaged one. Awesome work by the way.

Xibalbawax (author)  PaulMakesThings1 year ago
I used heat of 250 and print speed of 50mm feed 50mm. I tried all the variable but what seems most critical to a good print is the humidity of the material. Temp between 245-260 all worked well. I try to make sure that i print on low humidity days which are often in NM, that is until I get some sort of dryer.
That makes sense, because I got some nice prints when I first tried and then it stopped working, bubbling and steaming. I live in Wisconsin right by the lake so there's plenty of humidity in the summer. I'll try drying it in an oven and see if it works out better.
jarikcbol1 year ago
I think the claw prosthesis would be less creepy if it was plain white or something. being skin colored, it just looks like some weird mutation.
Xibalbawax (author)  jarikcbol1 year ago
It works great for operating remotes for tv and cable
Xibalbawax (author)  jarikcbol1 year ago
the nylon I used for this is naturally clear to white. It absolutely looks like a mutation and it is better than my original thumb for several applications.
chaotick1 year ago
Brilliant! I don't know anyone that would need this - but such a cool demo of 3d printing!
Xibalbawax (author)  chaotick1 year ago
samalert1 year ago
This is one of the wow use of 3d printing. When things like these are invented it makes you feel good in heart. This was a lovely project !
Xibalbawax (author)  samalert1 year ago
very cool!!, the claw thumb is a little freaky though. ... good how All around.
Xibalbawax (author)  incognito02881 year ago
freaky but functional
This is a truly life changing creation my friend and the benifits of the costing are fantastic. Well done indeed!!!
Xibalbawax (author)  BigBadgers20011 year ago
I surfed the web for months looking at various prostheses and there were none out there. I acquired a standard PVC cosmetic thumb and was quite disappointed, not to mention feeling light in the wallet with the $300.00 deductable.
elizruge1 year ago
Wow. made yourself a thumb!?! i can't even figure out how to paint a rock (just found THAT out ten minutes ago). I am beyond impressed. Sorry I didn't read it all (duh, can't even paint rocks) but again, wow. Kudos.
Xibalbawax (author)  elizruge1 year ago
I had to make one, there are no functional highly durable finger prostheses for those who actually use their hands for working.
Excellent job!!! And elizruge, your comment was amusing! :)
oops...ment to say.good job.
Bravo ur someone that probally agrees that this new healthcare isn't good
Xibalbawax (author)  TheMrCOOLguy21 year ago
you got that right
I love it my g pa has this issue
A snowblower accedent
Xibalbawax (author)  TheMrCOOLguy21 year ago
Your G pa would probably benefit from one of these prostheses
billbillt1 year ago
This is a great idea...
Xibalbawax (author)  billbillt1 year ago
kariswg11 year ago
how about just making a cast of your good thumb, or the thumb of someone with hands the same size a yours? Seems easier than 3D printing. Just an idea.
Xibalbawax (author)  kariswg11 year ago
you are correct about it being easier to cast and physically model a prosthetic. However once the intial model is made it becomes easier and less time consuming to scale this model to fit multiple persons and to make multiple copies. By the way I am a trained sculptor and do very much enjoy the creation of physical objects through non digital methods.