ASME Y14.31-2008 pdf – Undimensioned Drawings.
5.2 Gild Lines
When used, grid lines shall be added and validated for accuracy before the drawing Is started The pattern of perpendicular lines shall be equally spaced at a nominal distance apart. Pnienisi grid line spacing is 5.000 in. (127 mm) or 10.000 in. (254 mm), Drawings with grid lines shall indicate directly or by reference the dimensions of the grid with a note such as (;R1D LIFS 10(H) IN. (254 MM) ON CENThR. The pattern of grid lines may be parallel to the drawing borders or rotated at an appropriate angle to suit the presentation of the item (see Figs. Sand 13). When grid lines are rotated, dimensional accurac points are required independent of the grid for validation and verification. Portions of grid lines may be removed in areas where they Interfere with the clarity or presentation of pictorial views. An area of approximately I in. (25.4 mm) diameter at the grid intersection points shall be retained.
5.3 DImensional Accuracy PoInts
Dimensional accuracy points may be constructed as shown In Fig. 14. Dimensional accuracy points are frequently identified by term.s such as, trammel points. grid check points, and material validation points. 11w type and size of dimensional accuracy points shall be consistent throughout the drawing and shall be placed in a rectangular pattern surrounding the item. A minimum set of four dimensional accuracy points shall be placed within the drawing border. Dimensional accuracy points shall be validated for accuracy. The horizontal and vertical dimensions between dimensional accuracy points shall be controlled directly or by reference. When controlled directly. extend arrows horizontally and vertically with dimensions indicating the distance to the adjacent dimensional accuracy points in the pattern (see Fig. 15). When the drawing exceeds the capabilities of the validation and verification process, a minimum set of six dinwnslonal accuracy points shall Lw provided (see Fig. 16). The center dimensional accuracy point shall be constructed as shown in Fig. 14. The dimensional accuracy points shall be equally spaced hor. izontally and equally spaced vertically.
5.4 RegistratIon Marks
Registration marks arc used in place of a grid system on drawings depicting artwork type items. A minimum of three registration marks shall be placed in a right triangular pattern surrounding the artwork pattern (see Figs. 6 and 17).
6.1 Split Views on Same Sheet
When views of the item are split on the same sheet, there shall be a minimum image overlap of 3 in. (76 mm) from the designated common reference (see Fig. iN).
6.2 Split Views on Multiple Sheets
When views of the item are split over multiple hcets, the views shall have a minimum image overbp of 3 in. (76 mm) from the designated common reference. Sheets may be positioned one above the other or side-by-side when designated common references arc used. When two or more sheets are joined in this manner, a sheet arrangement diagram shall be provided on the first sheet to indicate the relative positions of the sheets and as an aid in selecting the sheet on which desired information is located (see Fig. 19).
7.1 GraphIcal Tolerances
All features of the item shown in the graphical representation shall be drawn to a tolerance of ±0.010 in. (0.25 mm) of the actual size and location.
7.2 Item Tolerances
7.2.1 For contour definition drawings. templates. and comparator drawings. the lines defining an undimensioned item shall be considered as being the true profile. Tolerances shall be applied to measurements taken from the center of each line.
7.2.2 For wire harness drawings, the lines defining the center line of the wire harness shall be considered the true location and length. Plus or minus tolerances shall be specified on the drawing indicating the tolerance for the length of th wire harness.
7.2.3 For printed circuit boards, the lines defining the conductors shall be considered the true location. Tolerances are based on the components grid pattern per IPC-2221.