Some components do not have an appropriate ready-made hole. For “old-school” through-hole components like these, the actual chip is only a small fraction of the size of the package. That means that you can actually drill through the outer part (where there’s just plastic and the copper leadframe) with a “regular” steel drill bit. (For smaller packages, or if you need a hole closer to the center, you risk hitting the chip– and we recommend that you avoid it. Not only is it harder to drill through, but it carries a risk of spreading toxic dust.) You can start by pressing the chips into firm foam (e.g., black antistatic foam) to protect the leads while you drill. We used a 1/16″ drill bit, but found it pretty dull after drilling through just two packages. Presumably, this is because of the high silica content in the black epoxy encapsulant (which also gives the package high thermal conductivity). After drilling, you can deburr the hole (if necessary) with a larger-diameter drill bit. And, remember to clean the chip thoroughly to remove any excess dust that may be present.
On the back side, bend the leads of the pins back so that they are less “pokey” and so that they don’t catch on long hair. The wire hangers can be made of any appropriate wire– we used 1/32″ diameter stainless steel wire, but titanium would be a better choice, and precious metals can be used as well.