Terminator Arm that WORKS!

by AntsinAfrica May 19, 2016
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Very Cool design, is there a way to separate the parts in the grouped sections, like the fingers , so I can print individual parts, thanks and great work Matt

if you use Slic3r you can separate parts with a single click

That's cool!
If it becomes "if you use slic3r you can design it with a single click" . . . then I'm in trouble!

Hi Matt

Thanks, Yes, there is a zip file with the individual parts called Terminator arm obj's that contains all the individual parts.
I thought I had the .stl zip file uploaded too, but I see it is not here. I will look into that if you need the stl's.

Fantastic design! I just bought your model on CGI Trader, and am glad to see you have the model for the arm control there too. Well worth the price! The smoothed versions of the files on CGI Trader are much nicer, and the PDF manual is very handy.

I'm currently printing in ABS at 90% scale, and will be vapor smoothing and nickel plating all parts to give a more "authentic" look and feel. I'll keep you posted.


what do you mean by "The smoothed versions of the files on CGI"? The aceton smoothing process is done after the print for my understanding, am I right?

I mean the more detailed ("smoother") files on CGITrader. Well worth spending money on - you'll get much better results compared to using the files available here. New CGITrader users get free credit, so it won't cost you the full $20 (IMO, it would be well worth $20 anyway). As for acetone smoothing, yes - that's done after printing.

Hi there,
The Wrist Assembly again has incorrect Parts.
You uploaded the File Wrist_Assembly_Fixed at some point, but its not there anymore (i still have backup of the file).
Can you look into this?


Hi Rodney

Wow! You are correct, I did replace the file a while ago, but it seems to have vanished and replaced with the old one??
Very odd!
I have re-uploaded the file (wrist assembly fixed) and I added the smoothed version of the wrist ball clamp.
Hopefully it stays this time.
Thanks for letting me know!

What's the default scale for this arm?

The scale of the arm without the base is 600mm or 23.6 inches high.with the base it is 670mm or 26.3 inches.
It's big because the small parts would be too small to print if it was smaller.
I plan on redesigning a Version 2 at some stage, which will be a smaller size,

Seriously cool project! Something that I'm in the process of printing right now. After printing the Index Finger, the parts seem a little tight to move as freely as they appear to do in the video. I'm printing in PLA not ABS, so I guess a bit of sanding will be needed. So far so good though, looking forward to following this guide through until completion!

Awesome! I'm really glad you like it.
Yeah, the parts will need sanding. This was my first big 3d printing project, so my tolerances were probably a little too tight.
Version 2 (if I ever find the time) should be much better in accuracy, strength and tolerances.
Good luck and give me a shout if you have any questions.
Send pics or links if you can, I would love to see the finished project.
Thanks for the cool comment and have a good one!

He hello! i have try it to print the finger stuff first, and it will not work good. the small part what need support is not good, i see in your film also that the support is to much filled between the small gaps, how do you get it out? i printed serveral time to try to take it out, and try all kind of settings as well. but the small parts will be not done. even when i use a blowerpipe to cool down the little things very quick.

please help, and maby you have the finger parts all lose, so not in combined set of finger pairs, so i can print the small things seperated :-)

Further i have to see that you did really a nice job !!! really cool project :-)

Thank you so much, but sorry for your troubles.
It is better to print each part on it's own. You can divide up the parts in cura.
I'm not sure about other slicing software, but in Cura, you right click and select (split object into parts).
The trick to printing the fingers is to make sure your overhang angle for support is between 65-90 degrees.
I sanded the parts smooth, but I did not struggle to remove the support.
I hope you have success. Also, sorry for the late response. Unfortunately my day job took up all my time.

What software is compatible with the files?

I uploaded obj and stl, so it should be compatible with most programs.

Hi! :) i print everything, that looks great but i cannot found tubing! Where do you takes it?

I'm not too sure. I'm in Africa, and things are different here.
I will have to make sure I use a common size worldwide on the next one.
Sorry for the late reply.

Hi, where do you find the spings?

HI. You can find them on Amazon or eBay.
If you're lucky, then you might find them at your local hardware or even a music shop?
Just look for 4mm tension springs about 15-20mm long. I cut mine to the correct length.
The springs must move freely over the shafts and inside the Pistons!
Here is a link to the Amazon springs -
I hope this helps.

Other question on the hardware...where do you takes the steel rod?

I say and full of mistakes nor does it make the error slicer have email could send you photo

Yes please, you can send photos to - antsinafrica@gmail.com
I was not able to download my own files, so something is wrong.

The parts appear all defragmented and the program I use and repeat

Do you mean low resolution and not smooth or rounded?
I grouped and uploaded the original un-smoothed parts here and the individual smoothed parts went to CG Trader.
The reason was so that you guys can modify it however you want, but also to lower file size.
If that's not the problem, then I really don't know? I will have a look.

Good evening all your files give the error

Hi. Sorry to hear that!
Can you please tell me what error you are receiving and what slicer software you use?
I will then be able to find out how to correct the problem.
Thanks in advance.

You're a f*ckin rockstar mate! I love this

Lol! Thanks! Comment of the year!
If you haven't seen it, then follow this link to see the video of the Arm control - https://Youtu.be/E_jsPH9SRjk
The final arm on the lit stand worked out really well!
It took so long to design the base and control, that I had to put the model up for sale on CG trader. But it's Cheap, I think? $10?...
I will also be uploading free electronic and mechanic versions of the control for those that are already broke from buying their printers. At a later stage, I will also design an update of the control that will enable full wrist movement.
Thanks for commenting and have a good one!

That video further proves my initial comment, you're a fcking ROCKSTAR! Focusing solely on the video alone... the fx and post work, as well as taking the time to timelapse and stop motion the assembly, demonstrates the thought, time, and effort you put into this. It was a real production and the end product was well worth all of the effort. The little added ant making a visit in the video. Fcking brilliant.

You don't get the credit you deserve. I will change that.

Wow! what can I say? Other than thank you, thank you, thank you!
I won't lie, I'm sitting in deepest darkest Africa, almost broke and despised by most around me. (you may have heard about the ban science movement here in SA? LOL!) So that statement gave me goosbumps! Like they really really like me...Har har har!
But seriously, this is just the start, I have 30 years of ideas waiting to exit my brain. Thanks to you, and the love on this site, you will get to see them all.
You gave me a nice idea! For being the first person to spot the ant, you win...umm?, something...? (looks around)
A mini terminator arm perhaps? In the future I will offer 1 model from my CG Trader collection, but there is not much up yet.
You have built some impressive stuff yourself, but is there anything you would like me to create?
Thanks again!

Hello, i am trying to print with PLA but no success, i started with the finger index and got a weak part and the small details got broken. Any help?

Hi there! Sure.
I suggest you start by breaking each finger group into individual parts and print each part separately.
I grouped them to avoid confusion. Cura allowes you to do this, but I don't know about other slicers?
There are only really three ways layer bonding can fail:
1- incorrect extruder temperature 2- incorrect speed, 3- excessive time between layers (if speed is high).
Or just inferior filament.... So it's a balance, but working with each part at a time improves your chances of success.
It minimizes time between layers, so the layers have a better chance of melting together.
I hope this helps.

Love your video mate, nice job!

Thanks! Very much appreciated!
Have a good one!

Hi there,
The Wrist Assembly has incorrect Parts.
In the Video you slide the wires through the MIddle of the 2 Parts that get screwed together on the PVC Tubing and in the .obj of the Wrist assembly there is no such slot. I dont know if this is wanted but i made a little schematic with my advanced paint skills to illustrate the problem (if it is indeed one).


Just wanted to tell.
I also have a Question regarding the Spring and the Aluminium Rod for the Fingers. In the Video you slide the Spring in the tube, then the rod and then you put the cap on it. How are the Rod and Spring holding together so the rod is moving up and down regarding the position of the Wire? I already Printed alot of the Finger Parts and modified the Mech a bit since i did not get it to work the way you designed it. It would be nice to know if i missed something there.

Best regards,
Rodney McKay

Hi Rodney

Yikes! Thank you so much for letting me know! I can't beleive I missed that!
I found the correct model and uploaded the files (wrist assembly fixed)

For your troubles, I have uploaded the mini version (120mm or 4.72" tall)
I made all the surfaces intersect, so it does not move, but it's cute.

As for the spring:
I crimped the spring slightly to grip the rod (the side where the string is tied). It occasionally pops out, so not ideal.
I used a piece of an old car ariel, but If I had alluminium rod, then I would have drilled a teeny tiny hole on the end and then fed the end of the spring through it with a touch of glue.
I am sad to hear you are having trouble with the fingers! The fingers segments and levers only fit properly one way.
It's a bit of a puzzle if you mix the fingers up. This may be the problem? I hope so, or I messed up somewhere!?
If this is not the problem, then please send me a snapshot or more info, and I will see what I can do.

Best regards
Anthony Williams

Hey there,
Would it be possible to include the Length and the Width of the Tubing needed?

Best regards,

Cool, no worries. I added a drawing with the piston dimensions to the images above. Just scroll to the end.
I also added a version 2 of the piston cap that has the same Inner Diameter as the piston base. Mine is different...
I think the drawing will explian it nicely.

 Thank you so much for this.  It must have been a lot of work.  I'm in process of printing now.  I remeber watching this movie as a kid and always wanted one.  I remember when T2 came out, they had a contest, (I think it was either Coke or Pepsi too long ago to remember), where you could win one.  Now, thanks to modern electronics and some ingenuity, it's possible to own one.  So, thank you again very much for making this.    

Hey cool! You are most welcome! It was kind of hectic to figure out, and the video just added to the complexity.
Please let me know if you find any problems. It was created at lightening speed... so ...?
If you like 80s stuff, then you will like the 80s V series Fighter ship replica I built. I will upload that soon.
You can see it, and others at : http://antsinafrica.co.za/

Hi. You can place STL files? The OBJ file is incompatible with the REPETIER-HOST.
Thank you.

Repetier "Object Not Manifold" Problem.

There you go, STL files uploaded. If you can't open a rar file, then I can upload individual files.
If you have any problems, let me know and I will do my best to help.
Have a good one!

I'm new to this, so I ask for advice.
I am respectful and patient, but if you do not want to share the STL files, just tell me, I do not get angry.
Also, if you can´t upload STL files, ¿can you tell how to convert your .OBJ files to .STL files?
Best Regards.

I'm so sorry! I dont mean to ignore you. I have been nailed down with work. :-(
I will gladly share the .STL files. I will upload them Tonight (SA time).
If you can't wait, then all I will be doing is loading each .obj file into cura and then clicking on
File / Save model, give it a name and make sure to add .STL at the end.
But as I said, if you dont want to mission, then I will upload them later.
All the best!

amazing! & very nice videos!!

Thanks for taking the time to watch and comment!
100 good karma points to everyone!

Great work! I was thinking about if you can make an eNable hand out of it?

Thanks! Great minds think alike, I was planning exactly that!
The finger design has a useful feature of mechanically locking in place when closed due to the leverage angles (death grip!)
So This would make it easy to carry heavy objects.
I will probably redesign it to be stronger and closer to a real hand and integrate the finger leverage design, but I also love the idea of a cheap usable prosthetic hand that looks like the movie prop...
So I will probably do both...
Stay tuned!

As a part of eNable Budapest I would be happy to print terminator arms/hands for kids who needs a 3D Printed arm/hand.
Waiting for your next awesome design :) !

Great work! Can you tell em more about your acetone brushing process? Last item I tried everything just got gloopy. What's the secret? Lots of acetone and cleaning the brush regularly?

Thanks! Sure, I use a very clean soft bristled brush with a wide head and work very quickly and lightly.
The trick is to coat the piece VERY quickly in ONE thin layer and then put it in the sun to dry for 5 mins.
No area should be covered twice unless the previous layer has dried properly. It WILL start melting quickly.
It's literally like - Grab part and brush, dip tip in acetone, brush brush brush, stick in the sun and leave. 1min or less.
You don't need much. You can wipe the brush on a paper towel to remove excess if the brush is picking up too much.
But the acetone should never run! Obviously this only works with ABS!
For best results - sand the part first to remove print lines, use a thin wide coverage brush & use clean acetone when brushing.
I hope this helps. If you get it right, it looks really good and seems to make the part stronger.
Have fun and good luck!

Thanks! Working hard on the sequel... "The control mechanism(s)"
Going to be awesome!

Nice work! The scale is a little large but hey that's what 3D printers are good for!

Thanks! Yeah, I like to imagine Arnie being much bigger than me, so I scaled it up about 30%
It probably makes it a bit easier to print and assemble too.

Everything about this is amazing.
The engineering the print, the video.
This is inspiring work, thanks for posting it.

Wow, Thanks! Your comment is inspiring!
Thanks to yours and the other comments, I will definitely be posting more.

Is the video posted the build video you mention or are you planning another video?

The build guide is done. Hope it helps!

I was planning a video on the control mechanism, but I will include a detailed build process somewhere in it.
My goal is to make entertaining, HQ, easy to understand videos about cool, easy to build projects, so suggestions are welcome.
Good things take time, so please be patient.
Coming sometime : Terminator arm control - atomic bomb flash drive holder - V fighter with doors that open ( from the 80s tv series) - super girl - little boy replica - adjustable iPad stand with built in horn style amplifier - etc - etc.

Hell of a video. Nice Work

Thanks a mill! Making the arm was the quick part... :-)