PT XYZ plans to produce coconut shell briquettes. Currently, PT XYZ already has a hammer mill machine that will be used in the production process. A hammer mill machine is a machine that serves to smooth the material. Before carrying out mass production, a simulation is carried out first. The manufacture of briquettes found obstacles in the process of grinding and screening. Coconut shell charcoal that has been milled and entered is partially retained and cannot be released to proceed to the next process. The grinding result is larger than the screen size, which is 1 to 2 mm. In the manufacture of briquettes, it is expected that the grinding results are less or equal to 0.4 mm. Based on the identification of the problem, the alternative solution chosen by the researcher is to redesign the hammer mill machine, especially on the blade and screen sections. The design is done using the reverse engineering method. There are five steps in designing using this method. In the study, it was found that the second design was a suitable design to be developed because it was better than the existing state. The mill results were obtained with an average of 0.0343 mm and a grinding time of 186.807 seconds. The fineness values and the grinding process time were obtained through simulations using the EDEM 2022.1 software.