ALPHABET OF LINES Flashcards
Line types and conventions for mechanical drawings are covered in ___________.
ANSI Standard Y14.2M
This is what we call the lines used in drafting. Wherein each segment, line, point, thickness has an equivalent meaning.
Alphabet of Lines
ANSI stands for?
American National Standards Institute
There are 4 different and distinct thicknesses of lines in orthographic projection
Very Thick, Thick, Medium, and Thin
Types of lines in order of preference:
– Visible (object/feature) lines
– Hidden (dashed) lines
– Cutting plane lines
– Center lines
– Break lines
– Dimension lines
– Extension lines/Leader lines
– Section lines/Cross-hatch lines
- are continuous lines used to represent the _______ edges and contours (features) of an object
- most important lines, they must stand out from all other secondary lines on the drawing
- Line weight – thick
Visible Lines / Feature (object) lines
- are short-narrow dashed lines. They represent the ______ features of an object.
- should always begin and end with a dash, except when a dash would form a continuation of a visible line.
- Line weight – medium thick
Hidden Lines
- used to indicate the termination of a dimension
- must not touch the feature from which it extends, but should start approximately (2 – 3 mm) from the being dimensioned
- They can also show the ________ of a surface to a theoretical intersection point
- When ________ ________ cross other extension lines, hidden lines, leader lines, or centerlines, they are usually not broken.
- For circular features, centerlines are used as dimension lines
- should not cross dimension lines
- Do NOT use object lines as _______ ________
Extension Lines
- used to show the extent and the direction of dimensions.
- terminate with an arrowhead on mechanical engineering drawings; a slash, or a dot in architecture.
- If possible, ________ _______ are aligned and grouped for uniform appearance.
Dimension Lines
- continuous straight line that extends at an angle from a note, a dimension, or other reference to a feature
- An arrowhead touches the feature at that end of _______
- At the note end, a horizontal bar (6 mm) long terminates the _______ approximately (3 mm) away from mid-height of the note’s lettering, either at the beginning or end of the first line
- should not be bent to underline the note or dimension. Unless
unavoidable, _______ should not be bent in any way except to form the horizontal terminating bar at the note end of the _______. - usually do not cross. __________or
extension lines may cross an outline of a part or extension lines if necessary, but they usually remain continuous and unbroken at the point of intersection. - When a _______ is directed to a circle or a circular arc, its direction should be radial.
Leader Lines
are applied to represent an imaginary cut in an object, so the interior of the object can be viewed or the object can be fitted to the sheet. Line weight is thick (0.5 – 0.6 mm).
Break Lines
- are thin, long and short dashes, alternately and evenly spaced, with long dashes placed at each end of line
- are used to represent the axes of symmetrical parts of features, bolt circles, paths of motion, and pitch circles
- Every circle, and some arcs, should have two ________ that intersect at their center of the short dashes –
“_________” .
Center Lines, centermark
- are thin, uniformly spaced lines that indicate the exposed cut surfaces of an object in a _______ view.
- Spacing should be approximately (3 mm) and at an angle of 45°C.
- is determined by the material being “cut” or __________.
- are commonly referred to as “________________”
Section Lines/ Cross-hatch lines
- consist of medium-thin, long and short dashes. They are used to represent alternate positions of moving parts, adjacent positions of related parts, and repeated details.
- They are used to show the cast, or the rough shape, of a part before machining. The line starts and ends with the long dash of (15 mm) with about (1.5 mm) space between the long and short dashes.
- Line weight is usually (0.45 mm).
- long-short-short-long lines most often used to show the travel or movement of an object or a part in alternate positions.
Phantom Lines
- lines show where an imaginary cut has been made through an object in order to view and understand the interior features.
- The line type is phantom.
- Arrows are located at the ends of the cutting plane line and the direction indicates the line of sight into the object.
Cutting Plane lines
