Introduction: Mechanical Hand

Picture of Mechanical Hand

My most successful project to date. And I have learned that it is fun to have another hand! Not to mention that its great in costumes and gives a great deal more mileage than any other costume props I have made. In total I believe this project took less than 20 hours (once parts were assembled) and cost under $40 (the springs were expensive!).

I have now begun a more advanced version of the hand which will be larger, have more accurately scaled dimensions, better aesthetics, and, best of all, digit movement from side to side as well as both front and back. It may be quite some time before completion though. 

Before you start, let me note that I made a left hand because I am right handed and wanted the ability to retain dexterity for everyday tasks while I was wearing the hand.

Also, credit where it is due, I designed this hand after viewing the most superb hand built by Aternox over at DeviantArt, and it seems I am not the only one, as a quick poke around DA shows.

This project is becoming more common so look around the web for variants and different styles. Another of my favorites (besides Aternox's) is beautifully made by IAteSatan also over at DA.

EDIT: A short video of the hand in motion can be seen here. I apologize for the poor quality - when I have some time I will try to record and upload a higher quality video.

Step 1: Materials

Substitutions and modifications to the measurements are encouraged! Also all of these measurements are approximate in nature and suited to the hand I built, but your scale may be quite different.

- 3/4" thick x 5" x 5" board for palm
- 3/8" thick x 3" x 2' board for wrist
- 3/4" thick dowel - 2' long gives plenty of spare, but most are sold in longer lengths

- 5 keyrings
- 5 wires of 1 foot each*
- Small eyehooks (40 minimum)
- Springs with a collective length of 1' unstreched - keep in mind that you are pulling against these so get an appropriately low strength
- 14 small (<3/4" wide) hinges and their screws (often included) (hereafter referred to as "small screws")
- Flat top screws (25 minimum) of short (3/4" max) length (hereafter reffered to as "large screws")
- 6 Round top screws
- 6 Washers to fit onto round top screws

- 1 unloved glove
- Canvas or leather for wrist strap
- Buckle or fastener of your choice for wrist strap
- Thread and needle
- Decorative pieces as you like
- Wood stain of your choice or, if you want to preserve the color of the wood, linseed oil gives beautiful results

*A note on the wire - This part is under stress, will likely break, and will need to be replaced. I have tried single strand copper, braided picture wire, and discarded nickel plated guitar string. Of these the guitar string has worked by far the best. I have not yet had to replace any of the guitar string. Single strand copper went very fast. Picture wire had a moderate lifespan. String, especially nylon string (low friction), may be another good choice but I have not tested it as It did not fit the aesthetic I was aiming for as well.

Step 2: Preparing the Wood

Picture of Preparing the Wood

I have drawn up schematics for steps 3 and 4 in order to guide you through the installation of the hardware. Before we get to that, however, we need to get the wood ready for the following steps.

Cutting the Wood

1. The Palm: The schematic provides the basic shape I used. Feel free to adjust this to your own desired shape. I used jigsaw to rough cut the shape and hand sanded it with a rough grit sandpaper (60) to do the finer shaping.

2. The Wrist: For me, the wrist was simply a 2' rectangle of wood cut to that length so that the end of the rectangle reached up to my mid forearm when the beginning of the palm of the mechanical hand extended about 6" from my own. Keep in mind if you change this length that there will be significant overlap of the wrist with the palm.

3. The Fingers: Take your 3/4" dowel and cut it into 14 1" long pieces. To form the ends of the fingers, choose five of these and sand these until the ends are rounded off as shown in the schematic.

Finishing the Wood (Maybe)
This is your first of two chances to add a wood stain or finish to the pieces you have cut. At this point you can choose your color and stain away. I used a Miniwax "Early American" stain. Allow the stain to dry before proceeding.

Alternatively, if you would feel more comfortable staining after you have predrilled holes for your hardware (safer in case of mistakes in drilling, but slower in terms of the procedure), then go through the next two steps (3 & 4) predrilling all the holes for the hardware, but not installing the hardware itself. If you make a mistake while drilling a finger joint, just throw it away and cut a new one. Then, after you have predrilled everything, stain the wood, allow it to dry, and install the hardware.

Step 3: Hardware: Bottom of Hand

Picture of Hardware: Bottom of Hand

We arrive at the fun part!
We start with the bottom of the hand because it is here we will attach the hinges to hold the fingers together. The schematics on this page will do a much better job describing where to place parts than I will do with words. As such please follow them for the locations of the hardware. You can view a sample finger joint side view down below the image to the left. For this step, ignore the hardware on this sample joint that is marked "not represented here". The hardware you will be installing in this step is as follows:

- One hinge between each finger joint and between each finger and the palm. The only screws shown on the above image are the small screws that go with the hinges. Be sure that the rotating pin of the hinge pokes out below the bottom of the finger or palm section it is attached to. Otherwise, the pin assembly will push the hinge outwards from its screws, thus making the screws less firmly attached and creating a gap in the joint when closed.

- One centered eyehook per finger joint as well as one eyehook on the palm at termination of each finger  and 5 in a line at the back of the hand (as shown). The wire will run through these eyehooks. As such, all the eyehooks should have their holes aligned so that the wire can pass through except for the eyehook at the end of each finger which should be perpendicular to the rest (so that the wire can tie off to it).

Step 4: Hardware: Top of Hand

Picture of Hardware: Top of Hand

We continue by installing the hardware on the top of the hand. Saving the springs for last and the attaching the wrist for second to last, we start out with:

- The "large" screws (larger than the hinge screws). These go into the end of each finger joint, with the head facing in towards the palm. These act as stoppers so that the spring does not pull the finger joint too far back and tilt the fingers past what would be the knuckle on a human. As such, do not screw these all of the way in: instead screw them in until the head protrudes enough that when you push the joint back against it, it is in a straight line with the palm.

- The eyehooks! On the top these act as spring mounting points. These go two to a joint (except for one on the last joint of the finger) and one on the palm at the termination of a finger. Alternately, if you do not have space to attach two eyehooks to a joint, or the distance between eyehooks would be too short for your springs, you can go one eyehook to a finger joint (as I ultimately did) and attach springs to either side of it. Screw these hooks in so that the holes are open perpendicular to the direction of the finger.

Now you can go for the wrist. Simply center the wrist board and screw it in with five of the large screws - four in a square and one in the center, as shown.

Lastly, lets add the springs. Cut your springs to length so that when you extend them to the gap they will cover, they will have just a little bit of tension. Its better to err on the side of too little tension (more spring) here because you can always cut down the length later to increase tension. Bend the end loops down perpendicular to the direction of the other loops to form the loops at either end. Use pliers to attach the loops to the eyehooks in the top finger joints. If there is no opening in the spring's loop, use the pliers to bend up the eyehook until there is enough of an opening to slip the spring's loop onto it, then bend it back into shape.

Step 5: The Glove and Wiring

Picture of The Glove and Wiring

The Glove
The glove for the hand is simple, but slightly time consuming to prepare. First of all, you must sew on or otherwise attach keyrings to the finger holes of a fingerless glove (or make a fingerless glove out of a ratty glove by cutting off the finger ends). Ultimately I used wire to attach the keyring, but it forms barbs that poke the user and I would not advise it as an ideal solution. You must also keep in mind two things. First, the keyrings will have a wire pulling on them at one point - reinforce this point to avoid problems in future. Second, the threads may fray the cloth of the glove. Sew in an extra patch of fabric around the edge if you have the time to prevent this fraying from becoming a problem.

After the keyrings are attached to the glove, the glove must be attached to the wrist. To do this, put a washer on the inside of the glove and drill it down with a short, round top screw into the wood of the bottom of the wrist. Do this at one other point on the inside of the glove so that you have two attachment points.

The Wiring
Now its time to make the hand work. For each finger, knot one end of your wire on the keyring and run the other end up through the eyehooks as shown in the pictures. When you reach the end of the finger, knot your wire so that it tugs the keyring out towards the finger just a little bit. Guitar string, while durable, will not make very nice knots. If you are using guitar string, you may have a metal cylinder with a hole through it at one end of the string. Push this onto one of the ends of the keyring and use this as your knot at the bottom of the hand. Unfortunately, I have not yet found a way to knot guitar string prettily at the top of a finger, but a slip knot serves for functionality. Repeat your wiring for each of the five fingers and your hand should be mostly operational.

Step 6: The Strap and Decorating

Picture of The Strap and Decorating

The Strap
The strap is really an area for your own creative mind. I originally had a canvas strap with two on one side and two loops on the other as a fastener  However, this was difficult to fasten and the hooks occasionally scratched the user's skin. Because of this, I replaced the fasteners with an old buckle I got by asking around. Any fastener of your choice will work for this, but given my experience, I would advise that you find one that is quick and simple to fasten and unfasten with one hand and will not cause pain to the user.

To attach the strap to the wood, cut a rectangle of canvas the width of the wrist and a length equal to your strap's width plus two washer diameters. Then, placing your strap under the middle of the rectangle of canvas, screw down four round top screws with washers into the four corners of the rectangle of canvas. Please refer to the above picture to illustrate this direction.

Once you have your strap and buckle in place, your hand is ready to go. Before you go romping about the city impressing people with your newfound limb extension, consider decorating the hand with metal bids, sprockets, screws, wire, ans such. Steampunk is largely about aesthetics, so do not skimp on this step if you want to create a beautiful product.

Step 7: You're Done: Give Yourself a Hand

Picture of You're Done: Give Yourself a Hand

Or give yourself a pat on the back. A high five? A handshake? Really, the possibilities are endless. Go forth and have fun. With this handy accessory, passersby will by handing out their complements freely.

Oh well, I've had as much of that as I can handle. I hope to see some beautifully elegant hands out there. Please leave a comment and a link to some pictures of your own hand-related creations. Thanks for reading!


Basp (author)2017-04-16

I love this! I'm looking to create one of my own, but I'm wondering about which strings to get and how strong they are. What is the wire diameter of the strings you've used, and would you still recommend that thickness?

Manick Yoj (author)Basp2017-04-16

I used nickel-wound guitar strings from the E-D strings. I don't recall the exact gauge, but from looking at comparable examples, I think it would be about a 14 gauge wire. The diameter can vary pretty widely, but a thicker, flexible wire will be less likely to wear and break (though a thick wire will be difficult to tie off at the ends). If you can change the geometry of the hand so that the angles that the wire has to bend are less extreme, that will also increase its lifespan.

Basp (author)Manick Yoj2017-04-16

It looks like, for some reason, autocorrect insisted on changing "springs" to "strings" for me. I actually meant the gauge of the wire of the springs. But this is great information as well!

Manick Yoj (author)Basp2017-04-16

Hmm, I'm afraid I don't recall what gauge the springs were - it's been some time. In terms of diameter, they were in the ballpark of .25" and I would estimate that they were about 20-24 gauge, but that's a guess.

endou (author)2014-03-28

i did it!!!!! it is awesome!!! thanks mate, it is really cool

Manick Yoj (author)endou2017-04-16

Great! Glad it worked out. If you wanted to post photos of your build here, I'm sure I and others would appreciate it!

hahns (author)2012-12-12

Great work!
One thing I'd suggest is to re-route the wiring for the thumb to the other side (near the heel of the palm) and rehinge the joint so that it can function better as a thumb.

karossii (author)hahns2012-12-12

That was my first thought as well; by angling it over and down to the base of the palm beneath the pinky, then wrapping it to the back of the 'arm' stick, it could both articulate more like a real thumb, and be activated by a more natural (inward, not downward) thumb action.

Manick Yoj (author)karossii2012-12-12

This is true - I am working on making a more sophisticated opposable thumb on my current model but its still mostly in ideas/sketches.

If I rearranged the hinging of the thumb I could run the wire as you have described however, there is a great deal of friction on severe wire angles (as i found from an original wiring layout), so tilting the wire back from near the pinky to the glove would be very hard to activate.

b-irwin (author)Manick Yoj2013-04-08

What kind of gloves are they? That style of glove looks really good but i can't seem to find them anywhere.

Manick Yoj (author)b-irwin2017-04-16

They're old canvas gardening gloves with the finger tips cut off. You should be able to find similar at gardening or home improvement stores.

joostm8 (author)2012-12-13

This is just awesome,this hand would be perfect if you wanted to make a "Handyman" costume (Bioshock infinite)

Manick Yoj (author)joostm82017-04-16

Admittedly, when Bioshock Infinite came out, I was pretty surprised how close the design was to some projects like this I'd been working on. I was pretty taken with the handyman design too.

Manick Yoj (author)joostm82012-12-14

I am really looking forward to that game. Never played bioshock 2, but I did love the first and I am pumped for infinite. I've considered a costume of that bent. Lots and lots of work certainly, but it would be very fun to build.

joostm8 (author)Manick Yoj2012-12-15

I can assure you bioshock 2 is a really good game, and I'm hoping infinite's going to be even better.

bctour7 (author)2014-08-28

I think the best wire to use for this application is piano wire. You can get it in lots of different sizes and even the thinnest is going to be stronger than you could break using it like this. Pretty reasonable cost too.

Mark 42 (author)bctour72016-01-21

Piano Wire = Music Wire = Steel Guitar String
But some are coated with a winding of very thin wire (to increase the mas w/o adding a lot more tension).
Dental floss might work - it's very tough to break (makes excellent kite string)

Manick Yoj (author)Mark 422017-04-16

The guitar wire I ended up using was from the lower stings of a guitar (because it's a lot harder for me to break those strings) and did have additional winding around it that helped protect it from wear. Piano wire or music wire may work as might floss. No comment. If you try it and it works, please leave a reply here for others!

vmmartins made it! (author)2016-01-29

Awesome project, just finished mine ;) for the wires, I used steel cable, 1 mm thick. It can't be twisted to lock it in place but I found that I could use some thin copper wire and solder to get the job done.

Manick Yoj (author)vmmartins2017-01-21

This looks great! Good luck with it and thanks for posting the photos here!

charlesl8 (author)2017-01-17

And is it possible to put a mold or plastic on the hand over all of it?

Manick Yoj (author)charlesl82017-01-21

You could put a mold over the pieces but it would have to be comprised of multiple pieces or else the fingers will be unable to articulate. Think of how medieval gauntlets overlap - it'll probably be something like that

Also, the eyehooks protrude pretty far from the fingers in my design - you want to find a lower profile way to rout the wires or the mold will be very wide for its length and make the hand look excessively fat and stubby.

charlesl8 (author)2017-01-16

Is it possible to make the arm shorter for costume purposes?i still need it to move the fingers and such

Manick Yoj (author)charlesl82017-01-21

Certainly you could make it shorter - there's nothing that changes the mechanism because of the length. However, having the forearm brace (the cloth that you strap on) far away from the glove means that pulling the fingers is easier because the arm is held in place more rigidly.

Freeshivokadoo (author)2017-01-16

How hard would it be to make a whole arm????

You may have some trouble effectively articulating the elbow and fingers both, and there's also a question of where on your body you would mount the upper arm of the mechanical arm.

If you do it though, let me know - I'll be interested to see how you dealt with both.

Jacobcanale (author)2017-01-09

How big should the springs be? 1 inch or 1 cm?

Manick Yoj (author)Jacobcanale2017-01-09

I recommend that the springs have about 1 foot of collective length - you'll have to cut them to size and bend the last coil in order to fit them to the hand, so there's no specific dimension, but each will likely end up in the ballpark of 3/4 of an inch unstretched.

Jacobcanale (author)Manick Yoj2017-01-09

Couldn't fine any 3/4 ones, so I bought 1 inch ones, you think that'll be good? Also, I'm planning to move the thumb more to where it would be on a human hand, should that cause problems?

Manick Yoj (author)Jacobcanale2017-01-18

It probably won't cause major problems, but you'll probably want to think about how you're routing the wire to that finger: the more the wire bends at any one point, the quicker it will wear. Try to avoid bends completely if possible, or if you can't, try to route the wire through a few eyehooks so that no one bend is as drastic.

Freeshivokadoo (author)2017-01-16

How well does the thumb move

Generationmatthew62 (author)2016-08-21

do you know how to post instructables

ودودا (author)2016-01-21


En Dabuwya (author)2013-06-22

How difficult would it be to scale this up to control a mechanical hand larger than your own?

Manick Yoj (author)En Dabuwya2013-06-23

Quite simple within a limited scale I would imagine - the pull-rings on the glove for mine were quite close to the base of my fingers and could still pull the mechanical fingers all the way in. If you moved the pull-rings farther out along your hand, you should be able to get a great deal more distance out of it. If you want to go bigger than that, you may need a mechanical system like a lever or simple pulley (and if you're building a hand big enough to need that, it may even fit).

I will use your plan for the costume but alter it with the number of fingers to three if people ask I'll tell'm "there's a man named manick yoj and he is the person I give the credit to

mwilliam2 (author)2014-08-13

i made this myself, i based it off of your idea but not completly, i made each individual finger from a plank of wood and i also made the thumb apposable like our actual thumbs, im very happy with how it turned out but i plan on improving it. Thank You for the idea!

sir_ghattas (author)2014-06-02

This is awesome, I've wanted to do one for a long time,I haven't looked much and you may have addressed this already, but a cheap alternative to expensive springs is to get them from clicking pens, they may not work as well but they're essentially free, just a thought. But again, awesome instructable, loved it!

mdoe825 (author)2014-02-20

just what we need for our odyssey of the mind skit. the best - Islands High School going to world 2014

pickleman1234567890 (author)2014-02-17


RedE-6 (author)2014-01-23

A great instructable! well done! I have made one of these myself with a slightly different design: - I suggest you move the thumb to a more sideways position, like a humans, study your own! - You could also connect the thumb string to the first finger string, as it is hard to manoeuvre your thumb to pull the string. - Plus, instead of the 'expensive' springs you could use elastic, as its much cheaper and loads easier to assemble!

j-vega (author)2013-10-28


YeGreatOne99 (author)2013-06-20

this would make an awesome buttscratcher

ajkcool (author)2013-04-20

looks like part of the handyman from bioshock infinite

kschmidt2 (author)ajkcool2013-05-06

Good to see I'm not the only one who immediately thought that

kschmidt2 (author)2013-05-06


ajkcool (author)2013-04-20

this looks like something from the handyman on bioshock infinite

Slay. (author)2013-02-19

Epic ible. together with another ible on giant costume making, planning to make giant robot costume with working heads up display!

Enkil (author)2013-01-16

If you do not mind, we have translated this manual in the Russian language and posted on its website.
A reference to the original course set
Thank you, gorgeous work!

Manick Yoj (author)Enkil2013-01-16

Haha, that is fine, though surprising. Thank you for the translation!

About This Instructable




More by Manick Yoj:Inking Pictures into CorksVertical Axis Wind TurbineKnitted Mustache (Built using Holly2's Instructable)
Add instructable to: