Drilling is one of the most important and fundamental machining operations. A high level of accuracy is required in drilling operations, especially with the advent of automation. Since a drill bit has a very complicated structure and plunges inside the work material during drilling, the drill deflection cannot be measured practically. However, it can be evaluated through the finite element method. An appropriate universal model for twist drills has been developed using 20-node isoparametric elements. The model is based on the basic parameters of the drill bit and automatic mesh generation is possible for any size of drill. Using this model the drill bit has been statically analyzed and the drill deformations, namely radial, angular and axial, were arrived at. The results are discussed in this paper. Further the drill bit has been analyzed for its optimum geometry. The optimum values of helix angle, chisel angle, point angle and drill margin have been suggested. The effect of feed rate and work material hardness on the three drill deformations has also been analyzed and presented in this paper.
