Hi all,

I was asked how the hinge of the Marble Cage was done, in particular the clearances etc.
I thought that it would be interesting to share this with the community: so here it is!

This hinge is not very usual (well, at least, I've never seen it elsewhere) probably because it's quite difficult to make it without 3D printing (interlocked parts) and also because it was born from my obsession of having identical and symmetric parts (obsession not so widely shared, unfortunately ).
It works in all materials I have tried: Stainless Steel, White Strong and Flexible and Transparent Detail.

Basically, this hinge is made of 4 torus (I guess I should say tori), two for each parts, but you can add more of them if you wish. On each part, the 2 tori are perpendicular and linked by a cylinder.

The diameter of the wire is 2 mm and the clearance is 0.5 mm. This means that the internal diameter of a torus is 3 mm and the external is 7 mm (5 mm for its axis)

Check this image, it should help to understand the dimensions and the position of each element (dimensions are in green, the rotation axis in red).


This video, show the hinge is action.

As usual, comments are welcome!

• Attachment: MC.jpg
  (Size: 95.00KB, Downloaded 446 time(s))

[Updated on: Thu, 09 September 2010 21:19 UTC]

You are welcome. I am happy if this can help.

Jeff, concerning the 0.5 mm, this is a minimal value that works well in this case, but be careful because it depends also on the size of the contact area.
Here is a picture to explain:

In the case of the torus, the surface in contact with the internal cylinder is very small.
But, if you replace the torus by a ring with a square section, this time the area could be significant, and, in this case, I suppose the minimum clearance c will probably depend on the height h of the ring (the larger h the larger c).
This is because the powder has to escape this small space.
So depending on the shape of the areas in contact you could have to increase the clearance to 0.75 mm or even 1 mm.
Good luck!

• Attachment: clearance.jpg
  (Size: 80.26KB, Downloaded 336 time(s))

[Updated on: Fri, 17 September 2010 08:47 UTC]