Unlike ductile metals cutting mechanism, the interfaces between fiber and matrix as a transitional layer experience mismatched deformation in machining process. In general, the most frequent operation performed on composite materials is drilling with a twist drill to generate a hole owing to their versatility and low production cost. However, delamination is one of the most common defects in drilling laminated fiber-reinforced composites and can cause a significant reduction in the load-carrying capacity of a structure. At the periphery, using such special drills as saw drill, candlestick drill and core drill, reducible to causing delamination damage than the twist drill. Experimental results indicated that the diameter ratio and feed rate have statistical and physical significance on the thrust force obtained with a core-candlestick drill.