Watermills, known locally as chhoskor, are the traditional method used to grind grains in many parts of the Himalayan region, including in Arunachal Pradesh. The indigenous Shertukpen tribe of West Kameng district in Arunachal Pradesh has a long history of using stone tools for grinding purposes with the help of watermills. The people of the area have consequently become skilled manufacturers of watermills for grinding purposes. This paper examines the process, steps and techniques involved in manufacturing watermills and documents the rich cultural heritage of the Shertukpen populace. To collect first-hand information and to understand the processing techniques, a simple chaine operatoire (operational chain) was applied to comprehend the entire process of manufacturing the region’s traditional chhoskor. ‘Chaine operatoire’ refers to the sequences involved in manufacturing an artifact or tool. The study found that the traditional craft of manufacturing watermills is disappearing. Documentation and other preservation methods are therefore essential if this endangered cultural practice is to be sustained and preserved.