Bigger On the Inside

What you have already assembled is practically a TARDIS, so you don;t really need my help anymore, right?

Well, that is: if you are building a shoebox or something.  But even the TARDIS USB hub pictured above as something that most people will avoid at all costs: an angled roof.  Even though the maths are somewhat elementary, most people won't attempt it because they have forgotten how to make geometry work.

So this step in the build for Tardis 1.0 serves a double purpose: it will help your TARDIS to look more like the real thing, and it will be an example to your children when they ask you, "but Dad/Mom: when will I ever use this in real life?"

The great thing about this is that it's all triangles, and triangles all behave in a very orderly way.  Here's what we know:

------------------------- START MATHS -------------------------

Well, here's the picture:

The base of the roofline is "A", and the distance to the center of the plane of the roofline from the center of the base is 42 mm, or "B" in this diagram.  The rise from the endpoint of "B" to the peak of the roof is 10mm, or "C".  "B" and "C" form the legs of a right triangle, and the Hypotenuse of that triangle equals 43.174mm.  That means the side of the roof panel has two legs, one which is 42mm (half the baseline of the roof) and the other equals 43.174mm (the hypotenuse to the roof's peak).  Therefore: "D" equals 62.232 mm -- which, for the sake of the accuracy of our tools, we will round to 60.2mm.

------------------------- END MATHS -------------------------

So you need to draw and cut 4 triangles on your mat board with a base edge of 84mm, and two equal sides at 60.2mm.  While you may have escaped the math required to figure this out, you can't escape the math it will take to draw these triangles -- because if they are not precise, you will not get an even roof with the slope we are looking for.

What you need is your caliper, a ruler, and your pencil compass.

First, draw a line with your ruler abut 90mm long.  Then, with your caliper, measure a length 84mm long.  when your caliper measures 84mm, set your compass width to the caliper to ensure accuracy.

Now: set your compass on one end of the like and draw a half-circle which crosses you 90mm line.  That will be your 84mm length.  Now use the same method to set your compass to 60.2mm -- and be sure to be as accurate as possible as you will be unsatisfied with legs that are 60mm or 60.5mm long.  They won't fit right.  Once your compass is locked in, draw half-circles as in the diagram above, putting your center point of the compass on each end of your baseline.  The place where the circles intersect will be the peak of your roof, and will give you two line which each equal 60.2mm in length.

Repeat this 4 times so you get 4 equal triangles, and then cut them out so that you have identical pieces.

When you have 4 identical pieces, you can assemble the roof.  To do this, assemble the roof topside-down, and secure one section to the next using tape.  Assemble in a clockwise fashion, making sure you have good alignment on each piece from the base corner to the peak/center corner.  When you have attached 3 of the 4 edges, your roof should still lay flat on your assembly table; when you tape the 4th edge together, the roof should "pop up" to reveal the sloping roof line.  In the diagram below, I have colored each panel a different color so you can see how the edges connect, and what the last step of the assembly should look like.

It may appear a little uneven at this point because it's not actually very well supported, but that's OK.  Once you have the roofline taped in a satisfactory way -- something that looks like the baseline is even all around -- apply superglue to the edges and set the assembly aside to dry.  If you're a more-daring modeler, you should tape the edges on the outside, pop the roofline, and then glue the edges with hot glue generously to give the roof line a very solid support.