Precision Machined Metal Dice

Precision machined dice made from pure, solid metal. Just like my abs. Amber Rix's wildly successful Kickstarter project will reward backers with a choice of 3/4" dice in 7 different unmixed, undiluted material types: Aluminum; Stainless Steel; Brass; Copper; Titanium; Damascus Steel; and--Yahtzee!--Tungsten. All have undergone intensely fancy mathematical calculations to account for their varying weights and Centers of Mass, and to ensure they remain Vegas-standards legal. More on that for the brainiacs out there later.

First, though, a mention that Rix was seeking $3,000 in Kickstarter funding. As of printing, with nearly two weeks left in the project's run, she has amassed over $100,000. Geez, people sure do like their metals and their games of chance.

And second, a rundown of the dice's different metal options, their weights, and pledge requirements. Note that all metals will have a brushed finish.

• Aluminum. Each die weighs 0.65 oz. A $12 pledge returns a pair anodized in the buyer's choice of Blue, Black, Red, or Clear/Silver.
• Stainless Steel. Weight of 1.92 oz each. $19 for a pair.
• Brass. 2.05 oz each. $26 for a pair.
• Copper. 2.13 oz each. $33 for a pair.
• Titanium. 1.14 oz each. $45 for a pair.
• Damascus Steel. Weight not listed. Rix was only able to acquire this pricey, sparsely supplied metal--traditionally used for swords and daggers--for inclusion in her project after backers' astronomical support of it started rolling in. A single Damascus die is $90, and a pair $170.
• Tungsten. 4.47 oz each. $98 for a single die. $196 for a pair.

Additional funding levels return master sets of precision machined dice, as well as candy assortments of Rix's metals. For $490, you'll get a Game Sample pack with a pair of all 7 kinds of dice she's fabricating. Get your pledge in before the project's close date of January 10, 2013. Anticipated delivery of the metal cubes is March 2013.

So you really want the math?

Fine, let's see how paraphrasing this goes.

Since each die is a single, solid, rigid body, it has a geometric center, or Centroid, that defines its Center of Mass. When considering rolling a die its rotational dynamics come into play, which depend not on its Center of Mass but its rotational inertia, or Moment of Inertia. The Moment of Inertia measures the resistance of an object to rotational acceleration about an axis. Should density or mass vary in distance from the rotational axis, the Moment of Inertia defines the resistance of that object to rotational acceleration.

Rix wanted to minimize the rotational Moment of Inertia of her metals so that, when rolled, her dice would stop at statistically even probabilities for each of the six possible outcomes. She was able to accomplish this using parasolid modeling to calculate the Moment of Inertia, and to instantly make structural modifications that would reduce the differential between the Centroid, the Center of Mass, and the Moment of Inertia of a perfect cube.

Each different metal die's face features (its 1 through 6 dots) have different drill depths to compensate for the mass of the material removed from the opposite face. This allows Rix to use parasolid modeling to match geometric Centroids to their corresponding centers of mass.

November 2013 Update: Rix's machined dice are now available for direct purchase through the CRL Products online store in materials ranging from aluminum to brass to copper. Follow the link below.