Spineless II: Poor man’s ball joints.

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



  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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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:


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.


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)



And off they go!



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:


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, everything was machined or built @ 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:


Another shot with my secondary model:


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



This is the end
Hold your breath and count to ten
Feel the earth move and then
Hear my heart burst again


For this is the end
I’ve drowned and dreamt this moment
So overdue I owe them
Swept away, I’m stolen


Let the sky fall
When it crumbles
We will stand tall
Face it all together


Let the sky fall
When it crumbles
We will stand tall
Face it all together
At skyfall
That skyfall


Skyfall is where we start
A thousand miles and poles apart
Where worlds collide and days are dark
You may have my number, you can take my name
But you’ll never have my heart


Let the sky fall (let the sky fall)
When it crumbles (when it crumbles)
We will stand tall (we will stand tall)
Face it all together


Let the sky fall (let the sky fall)
When it crumbles (when it crumbles)
We will stand tall (we will stand tall)
Face it all together
At skyfall

This is the end…

Or…is it not?

A story ends…a new stage begins…

I will soon be moved off from production to become a SMD machinist. I’ll be heading towards controlling not one but three SMT assembly lines. I have no fear in me from long workdays and odd hours, but I keep wondering what will happen to me. Will anything from the old me remain when the training is over and I’m on my own?

As said, I have no fear, but I do contemplate the fact that I might burn up quickly. I’m not sure my bosses take that into account.

I haven’t chosen the song lightly either. When it says we will “face it all together”, it’s because as long as I’m able, I am going to keep a journal, both in video and text, of what it is to become a machinist, what do you do, what do you learn, and if I burn up, you’ll see my fall.

On the other hand, I wonder if my new boss fully understands what he’s got with me. He hasn’t done any interviews, as I have been just hand picked. He barely knows me, just that I like machines, machining, electronics and stuff…but that I also don’t see my bosses as superiors but as equals.

If I see something wrong, I say so. I will always spoke my mind. I will also work more like a robot than a human (I don’t drink coffee, I don’t smoke, so I don’t loose time in nonsense. I like efficiency above everything else, and I don’t waste my time at work, or if I do it, it is in a fully approved way by the A.S. Enrichment Center).

It is interesting because I am going to apropriately meet him in a road trip across the country to get the machines. I don’t know if sitting in a car for 10 hours with your future boss is the best way of being introduced to someone.

Also, he doesn’t know that this is a reverse job interview. He doesn’t have to like me as a worker, I have to like him as a boss, otherwise I’ll pass the offer along to the next coworker who is adequate for the job. I’m not sure either where this self assurance comes. I know the job must meet some basics like let me play around, document things, carry my bag-o-tools, mount my own boards, use the tools for my personal projects, etc…plus some extras I plan to add to better fit the job timetable to my needs. Basically I don’t especially need more money (altough I could use it for something, sure.) and I don’t need being stressed, yelled, forced to overtime and work outside a normal job envelope. And since I don’t need that, I feel free to say no if all that doesn’t come with a set of bonuses and benefits as big as a mountain, apart from the money, I mean.

Of course there are still posts to be written (and some drafts to be published too) about the laser, the CNC router and if I ever finish the 3D printer, that too.

Because of too much KSP, I just feel like going too fast in a reentry…

Even more busy!

But I can show you the prototype:


Details from the hardpoints for the wings:



Here’s how it works:

Basically, the first disc acts as hardpoint for the brass screw. The second disc gets actuated by the piston and moves the first wing (the one wich travels further). After 45º, the third disc is engaged by the second and starts traveling sinchronously, lifting the second wing to the midpoint. Finally, after 45º (for a total of 90º) the third wing (fourth disc) is engaged, and everything travels a further 30º.
As you can see, everything rolls on ball bearings, even the engaging pivot has two per disc. Mostly because I can. XD
The other wing pivot is just a mirror image from this.

And here it’s moving under power: (@3.5Kg pressure) The wing doesn’t actually move all the way up because the cable was too long, but it’s adjustable so there should be no problem in there, just some fiddling around with lengths.

Some stats:

Machining of the discs, base design, and ball bearing whire pusher took 26 hours of mill and lathe. (includes some pneumatic adaptors).


If your new air compressor only has quick links, you don’t want to mess with them, and also, can’t find an adaptor for BA to push fittings, what do you do?

Lathe an existing one!


And talking about remachining…we don’t want no stinking flow restriction, do we?


Those are gas filters for cars, but I use them as inline filters for the laser.