In the past, HSS drills were used with a tip angle of 118 ° for the production of thermowells.  In order to achieve a possible uniform wall thickness, the tip was ball-shaped or spherical in shape.  The current state of production technology enables the use of special deep hole drills, which allow a nearly flat bottom to the bore.  For this reason, modern thermowells (eg DIN 43772) with a flat tip shape can be made.