Spineless II: Poor man’s ball joints.

Today I’m going to show you how the spinal prop ball joints where made:

Aria

Materials/Tools:

  1. Threaded balls.
  2. Polycaprolactone, a.k.a. friendly plastic.
  3. Access to a lathe, or a friend that has one for a small turning job.
  4. 3 lip chamfer tool (and power drill/lathe)
  5. Clamp.
  6. Scissors.
  7. Pliers.
  8. Ball’s appropriate allen key.
  9. (optional) Plastic dye.

First of all, you must understand what you want to do. You want to encase the ball in some material wich allows it to swivel freely, more or less something with this profile:

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Ideally, that would have the thickness of the support, but that presents a bit of a problem when the ball is already odd sized:

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I don’t have a 5.4mm drill bit for the anvils to encase the ball. Also, this kind of arrangement won’t provide any ball centering, so it IS going to be off to one side or another.

The solution? make a flange on the anvils so they fit snuggly in the hole of the support:

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That, of course, comes with it’s own set of problems, first of all, the odd sized holes:

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Again, I don’t have a 5.6/5.7 drill bit at hand (I usually only have x.9 bits to use prior reaming an even sized hole). You could always modify the thickness of the support so it gives you a better hole size, but any variation will mess up that fit. Nothing that a bit of ingenuity can’t solve.

For now you can build the anvils, taking care of drillng the holes for the ball slightly smaller than the contact points (I could have used 5.5 mm in this case, but went with 5mm because I didn’t want to take any chances). Also, since you’re at it, drill and tap one of the anvils so you can screw the ball in there, and doesn’t move on further operations.

They should look like this:

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Now comes the trick. Using a chamfer tool to eat away the corners, slowly fit both anvils until you can’t rotate the support around them (so their spacing when resting against the ball, matches your support thicknes, in my case, 4mm)

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And they will look more or less like this:

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Also, altough the drawings show a smooth bore, you must provide a means for the ball brace to stay in place, otherwise it will slip out of the support.
I just drilled a hole from the free end of the support and 2mm onto the cylinder’s body itself:

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And now it’s time to assemble some ball joints!

First, melt some friendly plastic (I dyed mine black for aesthetic purposes only, be warned, it’s a mess, use gloves!) then loosely press fit it in the hole you are going to use:

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Trim the excess:

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Now, before everyting cools, submerge both the support with the plastic and the ball holder anvil in very hot water to ensure that the plastic doesn’t cool quickly and flows around everything:

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(I couldn’t hold both and the camera at the same time ^^U )

Now, do both these steps QUICKLY!

Assemble the support with the hot plastic and the COLD (room temp.) anvil:

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Then press fit all, use the clamp to ensure everything stays in it’s place:

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Note how the plastic oozes from the hole, that’s good, it means it probably filled everything as supposed to.

Wait for it to cool a bit, then, grabbing only the support…

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Pull the cold anvil from it:

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If you look carefully, you can see the metal from the ball, as there is almost no material left between it and the oozing plastic from the cold anvil:

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Using the pliers, just rip off the leftover. If you didn’t wait long enough, the soft plastic will deform and mess up the joint. If so, just melt everything up and start again, friendly plastic doesn’t mind it:

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Assuming all went well, unscrew the ball with the allen key, but DO NOT, I repeat, DO NOT, wiggle the ball yet. Unless you waited a lot, the plastic in contact with the ball is still soft and will grab the ball and deform if you move anything. Leave it to one side to cool down and repeat the process. I was able to do three joints with a very hot glass of water, (didn’t had a thermometer to monitorize water temperature).

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If you applied enough pressure, that bit of flash should come off easily:

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Now you only need to break-in the joint. Move the axle to one extreme and then all around the range of the joint. That will loose it enough to move smoothly but still have very little play:

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And that’s it! now you wave fully functional ball joints for normal temperature conditions. I suppose you could thread the exit hole from the support and thread a nozzle from a 3D printer to inject ABS plastic. But that’s delving into high temperatures and performances I don’t need at the moment.

And now, let’s watch it one more time in this glorious shot:

I bet you didn’t mind the vertical video. XD!

Also, remember I said you needed to provide some sort of anchorage for the ball brace to hang into? Here’s what happens if you don’t:

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POP!

The art of packaging (VI): Dishware

So, we had to send some disc shaped boards full of sensitive leds. Using conventional bubble wrap bags was out of the question because the boards have protruding faston connectors, and the manager was pondering a solution for a while. This, then, was my moment to shine bright like a pulsar (you thought diamond, did you?).

Some time ago, I tried to push for a simple box packaging that would hold the boards in place using nothing but the rack-like foams I cut with the Guitar Hero. My manager allowed me to do one proof of concept:

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What happened next, was 33% faith, 33% self confidence and 34% luck:

So, I showed the manager and the sales rep the box with three boards in it. (spacers have been hot glued). They were unsure about it, so, with the box opening pointing towards them, I started to shake the box vigorously side to side and up and down, and the boards didn’t even nottice. But still they weren’t convinced, so, without a second thought, I let the box point downward (wide open) and started to shake it vertically like there was no tomorrow. Yup, that sold the idea to them without further questioning.

The luck part? Well, once I got back to my table with the box, the boards had slided a bit, so had I shaked it some more, they might have fallen off. ^^U!

But they didn’t, so, I won.

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Now add some foam on top so the boards can’t move at all (even if you didn’t add it, the boards can’t move enough to slide off their mounts)

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And off they go!

Spineless

Unlike Alanis Morisette, my model does not abide to any man. (ahem, ahem) still, the name was fitting.

So, apart from the winged mechanism, this is what I have been up to:

Aria

Fully articulated spine “reinforcement” (wich didn’t reinforce a thing, it’s just a fashion accesory) for a Steampunk Fair. (Eurosteamcon 2015)

Apart from the M3 balls and the axles, everything was machined or cut @ home. 28.5 hours of machining in it. I even developed a technique to make room temperature ball joints at home.

See it in it’s full range of movement, it’s hipnotic!

A very collaborative model allowed the pieces to be adhered directly to her skin:

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A different angle:

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Unfortunately, I ended up with a schedule so tight I just had time to machine, no photos of the process or step by step or anything. Altough it’s basic machining and reaming. The interesting bit, (the ball joints) will have it’s own post.

Here’s how cool it looked:

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Another shot with my secondary model:

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Also, one with both the spinal prop and the fairy wing mechanism:

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The art of packaging (V): Babel II

Just because you can, you should:

Babel 2

I just had 5 minutes to stack and dismantle everything (and I had even more pieces I was unable to put on top) so the tower leaned a bit just as I had finished. As I was going to grab my bicycle blinking light to put it on top as if it was a skyscraper, the tower fell on me, so I didn’t had time to take a photo, but luckily, my manager did.

Yeah, I still have too much fun at work. XD!