Hole pattern

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A hole pattern describes the arrangement of the holes for the screw connections of a pair of flanges .

General

The drilling patterns of two parts, which later z. B. be screwed, must match within a certain tolerance , otherwise the holes will not be on top of each other and assembly of the screws is not possible. Often, templates with drill bushings are made for production , which avoid time-consuming scribing.

Pipe flanges

The drilling pattern for pipe flanges is exactly characterized by the following parameters:

  • Diameter of the holes
  • Diameter of the hole circle of the holes
  • Number of holes on the bolt circle (this value can always be divided by 4!) << With standardized flanges according to DIN or ANSI
  • Position of the holes on the bolt circle (keyword: avoiding the so-called 12 o'clock position of the screws when installing the flange connection)

The hole pattern is determined by the nominal width and the nominal pressure rating of the flange connection and thus by the associated pipeline .