Introduction: Make Things Bend - Low-Tech Animation
Looking for a simple way to animate things? To make something move without the need for microcontrollers and servos, or unpaid interns hiding in a box all day, waiting for the right moment to move your contraption? Look no further! Look no further, because with a little string and some springs, we will make this thing wriggle!
(Also, check out the video if you are into that kind of thing).
Step 1: What's the Point?
Let me answer this question first, before I show you how simple it is.
The point of this is to make things move that do not require power, do not need to be protected from rain (like most electronics do) and that can be set up to work in a number of different ways. You can build something that will move part of your Halloween decoration as people walk by (i.e. step on a hidden pedal), or you can use servos to create "background" movement for a costume. You could even use this to make a (enjoyably crude) hand that grabs things and releases them.
Mainly, what I want to say is this: do not look at it as a wand. Nor as a cucumber. Look at it as a technique and what you can use it for in your upcoming projects.
Step 2: Tools & Materials
As always, there are different ways to go about this, and I will try to give as much detail on alternatives as maes sense. But as long as you have grasped the main concept, there are bound to be more ways than these to go about it.
- lathe - the tool of choice for making things round. You could also buy round stock and work with that to make your wand blank.
- miter saw - best suited for angled cuts. You can also use a handsaw, or, if you have the skills, a scroll saw. A table saw sled would be tricky since you need to cut at an angle, but it is not impossible to do that way.
- sander - to take off the sharp edges after cutting. I used a disc sander, but most sanders, even plain sandpaper, would work.
- drill press - you need a number of pretty straight cuts for this. You could probably get away with a handheld drill, but the drill press in combination with a vise offers the best precision.
- drill bits - you need two sizes here. One for a through-hole for your string, and one wide enough to accommodate your springs.
- forstner bits - also in two sizes. One to hollow out the handle, and one slightly smaller that should be as large as your thumb is wide
- rotary tool with mill bit - to re-shape a hole and make things smooth-ish.
- screw(s) - used to hold down string as the glue dries, and to keep the string from slipping out at a later stage.
- wood blank - to make the wand from. I used maple, but any kind of wood should do the trick as long as you can work it effectively. It will mostly get covered up anyway.
- scrap pieces - to support the blank on the miter saw.
- string - should be string and not too elastic.
- ca-glue - used to glue the string to the wood where needed. Other glues can work as well, but take exponentially longer.
- activator (optional) - If even ca-glue is too slow for you, you can use this spray to make it set literally in less than a second.
- springs - you need compression springs here, to keep the pieces apart. Their length is a bit of a tricky issue (there is a step on that), and they should have a diameter that you have a drill bit for. You will need your number of secments minus one in springs.
- felt - to cover up the mechanism. This is a matter of choice, and you can use other cloth or even other materials as well (see the step on covering it up).
- screw - I used one to keep the thread in place at the tip. You could also glue it in place or use a wooden plug.
- wooden ball -for the mechanism. You can also attack any piece of scrap to the string that will move freely inside the handle.
Step 3: Turning the Wand-Blank
For my wand, I used a maple cutoff which fortunately was long enough to give me the blank all in one. But since it will be cut apart anyway, you can either laminate smaller pieces together, or turn the handle and the actual wand section seperately. And since it will be covered up, you can use ugly or nondescript wood, and do not have to worry about sanding much.
The shape we are looking for has a thick handle, slightly longer than what you need to hold the wand by, and a section about twice as long that is roughly half as thick. The dimensions are not really set, though, so go with whatever looks best to you. Just keep in mind that the wand section has to be thicker than the diameter of your springs.
also, do not worry about getting the tip all pointy and pretty. Since it will get covered like the rest you can leave it flat and enjoy turning between centers till the very end.
If you do not have a lathe, there are a few other options. You could also use round stock to make the wand blank. Take a thicker one, drill a hole the size of the smaller one and glue it in.
Another option would be to sand the blank down to rough wand shape using something aggressive like the belt sander. I would recommend cutting away as much material as you can before that, though. A table saw or a bandsaw would work well for that. Just make sure that it is close to round in the end. This is important because the pieces will be rotated later, and any corners would stand out and making covering it trickier than necessary.
Step 4: Parting Off the Handle
This step is in preparation of the handle being hollowed out. Not only should you part of off to make that task easier, but you can, with luck, prepare a good connection for putting the hollow handle and the wand section back together later.
The idea is to pick the forstner bit you are going to hollow the handle out with and create a ledge on the wand with exactly that diameter using the parting tool. Then part the handle off beneath that ledge. It is better to go a little over, because you can still file away material later to make for a good fit.
Without lathe, you can implement this feature in your blank beforehand, especially if you are gluing together round stock. You can also just glue the pieces together, without the ledge.
Step 5: Cutting Up the Blank
Now we need to cut the blank up. The way you do it determines the way your tentacle/finger/thing is going to move. For this project, I did the following:
- I set my miter saw to a miter angle of 20°
- I rotated the pieces by (roughly) 120° after each cut
I also used auxilary fences - supportive scraps - to keep the axis of my wand in line with the actual fence. Otherwise, the thicker end would have caused some misalignment which, in retrospect, would not have made much of a difference. It would have made for unsafe cuts, though, so go and use that additional support.
Here is what these "settings" mean: I found it tricky to envision how this thing woud bend using the angles I chose, and I still do not have an easy way to do so. But maybe this helps you getting startes.
- The miter angle determines how far it will bend in that particular spot. You basically set the saw to half the angle you want. If you want a joint to go 90°, oyu set the saw to 45°. With my saw set to 20°, the end result per joint will be about 40°.
- The rotation is where things get complicated, and for two reasons. One is that is is a bit tricky to keep consistent. You could probably improve that using some kind of marks on the piece ot reference against. The other is that once you leave a flat plain, it gets that much harder to imagine in which direction the finger will bend. An easy method wround that would be to stay flat and make a wavy line just to get started.
Step 6: Sanding
This is simple and depending on how hard you want to be on your cover material later even optional. I used a disc sander to take off the sharp edge and any tearout on all the cuts. A piece of sandpaper would work quite well, too.
Step 7: Drilling
This operation (and the next) benefits greatly from the use of a drill press and a vise for precision or at least a semblance thereof. The objective is to drill down the center of each piece, first with a small drill suitable for a string-hole (I used 3mm or 1/8"). And since the cut faces are at an angle to each other, there is no way to rest it on the drill press table with easy.
I used the machine vise that came with my drill press, but you can also use a clamp to hold the pieces in place.
Step 8: On Hole Depth (also, Spring Length)
Now things get a little tricky - we need a ledge for the springs. To get that, we need a drill bit the size of the spring you have (or slightly larger). With that, we drill directly into the hole from the previous step. Use the vise (or a clamp) again, and center the hole as well as you can.
The thing is, with the faces being all at an angle, you will probably get some drift, but between the drill press and the vise, it should not be that bad.
But, I hear you ask, how deep should the hole be? Well, the easy answer is that it does not matter that much, because this project should be forgiving in that respect (unless they are way too short).
The long answer is that when you lay the pieces in their relaxed position (usually straight), the spring should be at ease. That means you need to place the center of the spring at the midpoint between the pieces, and drill as deep as the spring extends on both sides. If you found that hard to follow, check out the sketch attached.
Step 9: More Drilling
Also on the drill press, I hog out the inside of the handle using the predetermined forstner bit, drilling in from both sides. I also drill into the connecting piece between handle and wand with a smaller bit to get to the string hole, because I could not get the string hole all the way through.
Here you can also see how the ledge turned on the lathe is meant to work. I had to file it a bit to get it to fit properly, but it was a head start and saved me some headache in connecting the pieces.
Step 10: Assembly Required
Now comes the fun part - putting the pieces back together.
Here's the basic principle: the wooden pieces are rotated by 180° and connected with a piece of string that serves as a hinge. A string run through the whole wand can pull that joint together, while the spring will keep it apart.
To make that hinge, cut a piece of string about 2.5cm/1" long. Use ca-glue to glue about one half to the "highest" point of the starting piece. I used a screw to hold it to the wood, and activator to make things go faster. It might not be the cleanest way to glue, but it is definitely the quickest.
Then place the next piece tip to tip against the one with the thread, and glue the other end in place as shown. Leave a little gap between the pieces, though - we do not want too little slack, which translates as too much tension on the hinge when it is pulled together. Also, try not to soak the string with glue, because it will get pretty stiff pretty fast.
Step 11: The Central Thread
Once all the connections are made, add springs to every joint and run a string through the length of the wand. The best way to do that is this: thread through a piece, then through a spring. put the spring into the ledge on the first side. Then thread the string through the next piece and put the first spring in on both sides. Repeat.
To keep the string from slipping out of the wand again - it has been known to happen - use long screws to keep it in place.
Step 12: It's Alive!
And this is where you are almost done. The bare bones are finished, and they work as advertised. Pull the string, and the wand will become crooked or wriggle, even.
One thing you probably need to do is to keep the joints from opening up too wide. If they do, now only will the wand look broken, but also the spring might come out. To prevent that, I used more string. I glued the pieces to the wood similar to the hinges, but I did it in a way that they would still allow the pieces to remain in a straight line, as you can see in the last picture.
Step 13: Sewage (Not My Best Pun, I Know)
There are many ways you can go about covering this (see next step). I chose felt, even though my original idea was a little different. I wanted to use the darker green only and spray it with some kind of bleach that would leave yellow-ish spots behind. I did not find any substance that would do the trick, so I chose to dress it up as a cucumber. Well, that is what I did, effectively.
I sewed six strips together, three of each color. I then inverted this tube by wrapping one end with string and pulling it out through the rest. I did not measure anything for this but went by eye instead. it was a very narrow fit, but in the end, it worked out.
Step 14: Other Cover-Ups
If felt is not your cup of tea, fear not. There are other ways to dress this wand up. Here are some I considered but chose not to pursue:
- sticking with felt (or other kinds of fabric), you could "shingle" the wand by hot-gluing short strips to it starting from the bottom and working your way up. Every strip would cover the glue spots of those below, and it would allow the whole range of movement without bunching up.
- similar to above, you could cut out pieces to glue to the wand in a cone shape (similar to the pattern you would use to make a cone hat). They would also cover each other and allow for freedom of motion.
- Latex would work well to make this look like more of a finger or tentacle. I would create a mold either from wood or rolled up newspaper, dip it in latex or brush it on. Once you built up enough layers to make it sturdy enough, remove the core and place it over the wooden animathing.
- Another method would be not to hide the wooden pieces but to emphasize them. Embellish them using paint and decorative pieces glued to them to make them into a steampunk thing (works well with the springs), or carve them (using the rotary used in the enxt step) into the semblance of bones or other parts to make them look skeletal, zombie or maybe even robotic.
Step 15: One-Handed Operation
One important thing is still missing from this particular design. You need two hands to operate it, and that is not the best set-up for something that is supposed to work "like magic". You can, of course, combine this technique with motors, servos and any kind of variation thereof. But I wanted to go truly old-school, so here is what I did.
I used a wooden ball that I had on hand, threaded the string through the hole in it, and fastened it with a knot. If you do not have such a ball or bead available, you can use any piece of scrap that fits inside the handle. I would recommend cutting a small circle out of a piece of board and then drill a hole for the string.
This piece of wood has to be placed so that at rest, it sits close to the top of the opening we created, with enough room for the thumb to get above it and push it down. If the hole is not long enough to pull it all the way down to complete the desired motion, you need to lengthen that hole.
Step 16: Further Considerations
- Imagine a tentacle sitting on your front porch, coming out of the ground, apparently. Make a bigger version of this wand, use wax cloth instead of felt (to protect it from the rain) and make it so that when the string is pulled it will bend towards the walkway. But here comes the fun part - make a small ramp or something similar that people need to step on - not an obstacle, but something people will actually step on without much thought. Then, build a mechanism that makes the tentacle bend when someone steps on that. Yes, it could be a simple switch connected to a motor, but I imagine you could go low-tech there as well and work with a reverse pulley to turn a little movement into enough to animate the tentacle.
- Animating a tail for a costume seems like an obvious choice, but actually, I think there are better ways to make a tail that can go in all directions (and you can find them all here). Instead, when it comes to costumes, I would use this technique for tentacles (duh), snake hair or overly long claws. Small wings would work, too, although they are probably not very good at actually spreading feathers or something similar. If you do it right, combined a few pieces with different motors (or a gearbox) that continuously pulls and relaxes the string, you can get cool "background" motion for your piece.
- Consider a "helping hand". Something with fingers that grip in their "relaxed" state, i.e. when the string is not pulled. It could hold, say, a towel. And you could theme it as a zombie, a robot, a bird's claw, a knight or, again, something unspeakable. Now, if you pull the string with a foot pedal, for example, the fingers would straighten and the hand would release. Someone could then use the towel, then place it back and release the pedal.
- With a little improvisation, you could use the same technique to make your own Dune-style sandworm. And since I am old-school, I'll go with the classic design with three jaws. They do not even need to actually articulate - a single joint would work quite well. Unless you want the jaws to bend out slightly. And depending on your use case and which state should be the more common one - open or closed - you should design your worm accordingly.
- This one is actually based on a comment on the YouTube video (linked in step 2), and I think it is awesome. Build a mailbox that high-fives the mail guy when it gets mail.
I hope you can use this idea to make something, and if you do, share pictures!
Thanks for checking out this 'ible. Let me know what you think, and remember to be Inspired!