Father Singh was a skilled artisan, specializing in the creation of delicate and highly functional prostheses. The Society of Jesus commissioned him to design a pair of braces for Emilio Sandoz, whose hands were too damaged for surgical repair. The braces, fitted over Sandoz’s hands and extending toward his elbows, were both visually delicate and mechanically complex, intended to strengthen and assist Sandoz’s fingers, which only retained limited function. These braces were also noted for their lifelike artificial skin, which masked the mechanical components beneath and were designed to be activated by the wrist flexors, using electrical signals generated in the muscles of Sandoz’s forearms.

Despite their intricate design, these braces proved cumbersome and painful for Sandoz. Over time, it became clear that adjustments were necessary, though Sandoz initially endured the discomfort without complaint. Father Singh’s work was later supplemented by Paola Marino, a Milanese bioengineer, after it was determined Singh couldn’t correct the defects in the original braces. Singh’s involvement in Sandoz’s recovery, though ultimately supplemented by others, played a crucial role in the early stages of Sandoz’s rehabilitation.

Singh’s work also benefitted others, including Felipe Reyes, who lost his hands in a letter bomb attack. Reyes praised Singh’s brilliance and admitted that the craftsman’s prostheses had significantly improved his own quality of life after the injury.