If you want to enter the world of CNC with many inexpensive options, the only thing you can do is engrave. The main limitation for most of them is their ability to withstand cutting forces, even on softer materials like plastic and plywood. But engraving on aluminum or even steel is well within the power of these devices with such attachments. Maintain a reasonable depth of cut and you can mark almost anything. CNC is a great thing to learn right now - help your kids improve or improve their skills. This set of bits will help you with that.