This paper describes a programme of practice research that combines historical technology (small charcoal-fired furnaces) with contemporary digital making methodologies (digital CNC milling). The intention was to create small spherical granules of precious metal suitable for granulation, an ancient metalworking technique. The authors begin by providing an overview of granulation’s historical background and the different traditional methods used to create granules. They give an account of the equipment used in the physical experiments and describe the rationale behind specific design decisions. In particular, they reflect on the nature and properties of producing a reducing atmosphere inside the firing chamber of the furnace, and the relevance of this to the granulation process. They detail the digital making methodologies that were used to create setters made from graphite to encourage the formation of perfectly spherical granules, and how these relate to recent developments of the technique by contemporary makers. The project is a case study that demonstrates how practical reflexive experimentation can broaden our understanding of unrecorded but crucial skills such as fire management and the impact that practicing such skills in conjunction with digital methods of making can offer new insights into past technologies.