Manufacturing technology has the main role in the development of products. To secure the positions in competitive product development surface roughness is an important criterion. Surface roughness is a combination of finer irregularities over machined surfaces due to the inherent action of the production processes. Therefore surface roughness has received great influence on the proper functioning of machined parts which improves creep life, fatigue strength, corrosion resistance, and wear and abrasion resistance. This report highlighted hole-making processes and given main focus on the drilling operation. This work targeted to provide better surface finish and optimisation of machinability parameters for producing high quality of King Pin Bush. The combination of optimal machinability parameters which find out through RSM technique. RSM is one of the Designs of Experimental (DOE) techniques which is more promising analytical and statistical tool which provides the quadratic mathematical model for response parameters.