Contents
What do you need to know about dimensioning?
6 Dimensioning 1 Numerals. It may seem a bit basic, but a few exercises with the shapes of numbers comes before dimensioning. 2 Dimension Lines. The dimension line is a fine, dark, solid line with arrowheads on each end. 3 Extension Lines. 4 Dimension numerals. 5 Notes.
When to call out dimensions in a drawing?
When calling out dimensions that are over 12”, make sure ALL of dimensions are called out in total inches or feet inches throughout the entire drawing. Either 4’-5” or 53”, they both mean the same thing but if there is a mix of dimensioning it can become easy to look at 4’-8” and see 48”.
When do you use a progressive dimensioning system?
Progressive Dimensioning This method is adopted when dimension has to be established from a particular datum. The overall dimensions are placed outside the smaller dimensions this dimension is showed by the common reference line.
What do the arrowheads on a dimension line mean?
The dimension line is a fine, dark, solid line with arrowheads on each end. It indicates direction and extent of a dimension. In machine sketches and drawings, in which fractions and decimals are used for dimensions, the dimension line is usually broken near the middle to provide open space for the dimension numerals.
Is the final digit of a measurement significant?
In a correctly reported measurement, the final digit is significant but not certain. Insignificant digits are not reported. With either ruler, it would not be possible to report the length at 2.553 cm as there is no possible way that the thousandths digit could be estimated.
When to use arrowheads to dimension a space?
When dimensions will not fit in a space in the usual way, other methods are used to dimension clearly, when those crowded conditions exist. Arrowheads are placed at each end of dimension lines, on leader lines, etc. Correctly made, arrows are about 1/8” to 3/16” in length, and are about three times as long as they are wide.