What included angle should a drill have when drilling stainless steel?

A drill angle of 140° is recommended for drilling stainless steel. The reason for this specific angle is due to the hardness and toughness of stainless steel, which requires a more acute cutting edge to effectively penetrate the material.

A 140° included angle facilitates a sharper point that enables better chip removal and reduces the tendency for the drill bit to walk or skid on the surface of the stainless steel while starting the hole. This angle also helps minimize the friction generated during drilling, which is particularly important when working with materials that can work-harden or become difficult to cut as heat builds up.

Using a sharper point allows for more precise drilling and creates less wear on the cutting edges of the drill bit, prolonging its lifespan. Thus, when selecting a drill bit for stainless steel, the included angle of 140° strikes a balance between effective cutting and durability, making it the optimal choice for this material.