This study proposes a novel methodology for predicting specific cutting coefficients in a hybrid polyester composite reinforced with rubber and fiberglass. Composite materials, notably fiber-reinforced polymers, are widely used in various industries, including yachting, automotive, and aviation. Glass fiber-reinforced polyester is a common example. To reduce costs and improve impact resistance, waste tire rubber particles are often added to these composites. Experimental investigations were conducted to evaluate the effects of cutting parameters, including feed rate and depth of cut, on the specific cutting coefficient. Results indicate that incorporating rubber particles into the composite matrix significantly lowers the specific cutting coefficient compared to composites reinforced exclusively with fiberglass. This reduction is attributed to the rubber's inherent ability to absorb and dissipate energy during the cutting process. Additionally, the study demonstrates a general trend of decreasing specific cutting resistance with increasing feed rates, primarily due to the formation of larger shear zones and enhanced heat dissipation. However, excessive feed rates can adversely affect tool life and surface quality. The findings of this research offer valuable insights for optimising machining operations involving hybrid polyester composites and contribute to advancements in composite materials processing technology.