You want to select the proper bit for your downhole drilling projects.
The size of a bit and hammer is determined by application and job specification. It is best to choose a size of hammer that is designed for the intended hole size. A good hammer-to-bit ratio will result in better energy transfer. Better energy transfer results in faster penetration rate and less stress to the drilling components — in other words, it results in better reliability and an overall lower cost-per-foot.