Microsoft Surface is now a known quantity. It’s sold out on pre-order and has been tested to the hilt by tech pundits across the U.S (including this one). The Surface is an exceptional Windows tablet that, with its Touch Cover, can masquerade as a touch-screen Ultrabook. We know so much, but not everything. Here are nine behind-the-scenes secrets about the new Microsoft product, which I learned from those who built it.

1. It Really Was a Secret

Microsoft’s Surface team worked in secret at the company’s Studio B building in Redmond, Washington. Word has it that many at Microsoft had no idea what this team was doing. When I took a special tour of the building and all the rooms where Surface was designed and tested, we typically passed through two locked barriers and always under the watchful eye of some very stern-looking security guards. Those working on and testing the product were not allowed to take it outside. Though hundreds tested Surface, it was always in “locked offices, with the curtain down.”

The outside world was certainly in the dark. As Surface lead Panos Panay put it ”We had the great advantage of nobody was looking.” In other words, we were all looking at Apple, a company known for secrecy and always expected to deliver some fresh innovation to our doorstep. Microsoft innovates, but rarely gets credit for it. Yet it’s never been this secretive, and certainly no one expected a Microsoft tablet. So we weren’t paying attention. Panos said that during the Surface development cycle, they had “zero industrial espionage incidents.”

Even so, the June 18 announcement date came about because Microsoft realized they were getting to a point where it would be virtually impossible to maintain secrecy and chose to tell the story before someone else did.

2. The First Surface Was Cardboard

The Surface Tablet concept was conceived, in part, with the idea of “opening a book,” sort of like the long defunct Courier (though no one at Microsoft ever mentioned that dead project). I actually touched the first cardboard mockup, which was held together with Scotch tape and is surprisingly close to the final design. From that early stage, Microsoft’s small team of Surface designers spent months refining the Surface concept and progressed through “boxes” full of 3D-models, most of which were built with a Polyjet 3D printer. ID Studio’s Designers told me they “iterated until there wasn’t any 'ink' left in the 3D printer.”

3. Surface Almost Had a Lucite Keyboard

Microsoft Surface is a tablet, but it’s also one with a very close relationship to its snap-in keyboard. The product ships with a urethane-covered one ($599 bundle model) and a real keypad option ($129). That keyboard was almost a shiny Lucite panel, but studies on how users find home keys quickly proved that idea wouldn’t work. The resulting polyurethane is, Microsoft promises, “no shrink and super durable.”

4. Microsoft Had to Invent

Microsoft was so demanding about the size, shape, look, feel and tolerances of the magnesium-clad Surface tablet, that designers said they had to invent some new machinery to build it. The Windows RT-based product is designed in the U.S., but like most tech these days, it’s built in China. As a result, team members made more than half a dozen trips to China over the last year.

5. Surface Is 3D

Microsoft relied heavily on 3D printing to model virtually every part in the Surface tablet. All those parts are the created in the real world on hundreds of Computer Numerated Control machines. These are essentially computer-controlled vertical millers (kind of like Dremels). Studio B has a handful of them, but there are hundreds in Chenzou, China, where Surface is manufactured. Unlike human-controlled milling, these babies are precise to 0.5 microns.

6. Touch Cover Keys Labels Are Not Printed White

The 3mm-thick Touch Covers are almost as stuffed full of technology as the Surface tablet itself. Each Touch Cover is built in layers, with a carbon-fiber base, a thin layer of pressure sensors (that respond to grams-per-inch of pressure), a layer of white material and then the polyurethane cover. Microsoft showed me how a laser carves through the black cover to reach the white layer and label all the keys. Microsoft also spent a year figuring out how to develop a keyboard that would shut off when you folded it against the back of the Surface tablet. They settled on something they called “Flux Fountain,” which creates a mechanical interference and turns the keyboard off at just the right point in the rotation to the back.

7. Surface Display’s Resolution Is Lower Than the iPad by Design

Microsoft Surface Tablet’s screen is 42% larger than the iPad’s, but it has far fewer pixels. The company’s display expert, however, told me that the JND (or just noticeable difference) between the screens is far lower than one might assume. Since Microsoft focused on squeezing the LCD, touch sensor and Gorilla Glass 2 cover closer together, so the spaces between the three drop to 0.5mm (as opposed to 1 mm in competing devices), the refraction is far, far less on the Surface display. In the lab-based demo I saw, this appeared to be true. However, as I said in my review, the Surface display does not look appreciable better than Apple’s iPad Retina screen.

8. Surface Is Custom

There are over 200 custom parts in Microsoft’s Surface Tablet and it’s all squeezed together to remove pretty much all the space and air that might otherwise exist. For example, when Microsoft went looking for hinges for the signature, built-in kickstand, it ended up building new ones from scratch. The three hinges have built-in dampers that keep the stand from snapping against the back of the Surface. This picture shows a semi-translucent, large scale model of one of them.

9. You’ll See Surface’s 22-Degree Chamfer Everywhere

Microsoft is pretty proud of the sharply tilted edge you see on the Surface. It’s exactly 20 degrees and, if you visit a Microsoft store, you’ll see that same 22-dgree angle repeated over and over again.

BONUS: Surface RT Review