s_21_sonderteile

Pilot-drilling values

This standard establishes the hole diameter for thread rolling screws in accordance with DIN 7500 (part 1). The hole diameters have emerged from practical trials carried out by manufacturers and users. These are regarded as guidelines and are assigned to various materials and thread reaches. It is also advisable to examine the fixed hole diameters for the various types of thread rolling screws (whose rolling area is defined in the standard only by a maximum length) by conducting your own trials, particularly in mass production. Processes that lead to a strengthening of the hole wall during the creation of the hole (e.g. punching) can require hole diameters that exceed those of the guidelines specified in the standard. The outer crust means that these can also apply for cast holes. The standard does not take account of holes with special forms (triangular, octagonal, etc.).