Multiple Identical Features (nX) — One Note, Every Match

A numeral followed by X before a dimension — `6X ⌀8` — states how many identical features that callout governs: one note, six holes, one tolerance authority.

Definition

Repetitive features or dimensions are specified by an X used with a numeral indicating the number of places required: 6X ⌀8 THRU states the callout applies to six identical features. The notation multiplies the entire callout it prefixes — size, tolerance, and any geometric control attached — so all six holes carry one tolerance authority rather than six separate ones. No space is used between the number of occurrences and the X; a space is used between the X and the dimension.

Series, patterns, and spacing

Features repeated in a series or pattern take the feature count with the size: 4X ⌀6. Equal spacing takes the space count with the spacing dimension: 5X 20 means four intervals of 20 between five features. When it is difficult to distinguish between the dimension and the number of spaces, one space may be dimensioned and identified as reference. The distinction matters because the two counts are different claims: one says how many features, the other how many gaps.

The basic-dimension frame exception

Where X is used with a basic dimension, it may be placed either inside or outside the basic dimension frame — the one place the notation tolerates variation, since the box already marks the value as exact. Patterns located by position follow the same grammar — 2X M20 X 2.5 in the standard's own datum examples — with the pattern's location tolerance applied once to the whole pattern, not per hole. The spacing rules in full:

• No space between the number of occurrences and the X: 6X, never 6 X
• One space between the X and the dimension: 6X ⌀8
• With a basic dimension, the X may sit inside or outside the frame
• Between coordinate dimensions, X means by and takes one space on each side: 40 X 30
• When feature count and space count are hard to tell apart, one space may be dimensioned and identified as reference

The trap: X meaning “by”

The same letter does other jobs on the same drawings. Between coordinate dimensions, X means by — 40 X 30 is forty by thirty — and in that usage it shall be preceded and followed by one character space. Thread notes carry their own X (M20 X 2.5 is a thread pitch, not two features). When the number-of-places and by usages appear on the same drawing, the standard's note is to take care that each usage is clear — the drawing reads nX as multiplication, and everything else as words.