This chapter delves into the pivotal role played by technicians at the National Astronomical Observatory in dismantling, maintaining, and repairing instruments. Its aim is to underscore the convergence of materiality and the consolidation of knowledge, shedding light on the significance of their contributions, which have hitherto been neglected. By delving into their biographies, this study uncovers their indispensable yet often overlooked involvement in managing instruments at the frontier of their capabilities.