Blueprint Reading 131

Section View

A view illustrating a rotated section resulting from an imaginary cut in the part. Blueprints may contain a variety of different section views.

American Society Of Mechanical Engineers

ASME. An organization that publishes technical materials and sets industrial and manufacturing standards. Along with International Organization for Standardization, ASME provides written standardization for blueprints.

Two-Dimensional

2D. Having a length and width, but not depth. Flat shapes are two-dimensional.

Auxiliary View

A blueprint view drawn at a right angle to an angled feature of a part. Auxiliary views provide a full straight-on picture of an angled side that cannot be fully represented with a basic orthographic view.

Arc

A curved feature representing a portion of a circle. Arcs represent a curve or portion of the circumference of a circle.

Typical Dimensions

A dimension that is assumed to be the same for similar features of a part. Typical dimensions are followed by an X or the word PLACES.

Reference Dimensions

A dimension that is provided for informational purposes only. Reference dimensions appear in parentheses or are marked with REF.

Blueprint

A document that contains all the instructions for a particular part and communicates all requirements necessary to manufacture and inspect a quality part. There are three elements: the views, their dimensions, notes.

Drawings

A document that contains detailed instructions to make a part. Drawings, or prints, contain dimensions, directions, and details to guide employees in metal cutting operations to machine a part and its features.

Orthographic View

A drawing often used for blueprints that communicates the shape and size of an object in two dimensions. Orthographic views present all the design elements of a part through a series of illustrations, each showing one of its necessary sides from a continuous perspective.

Isometric View

A drawing that communicates the shape and size of an object in three dimensions by showing three sides of the object from one perspective. Isometric views are not frequently utilized in blueprints.

Cutting Plane Line

A line in a blueprint that represents the path and position of an imaginary cut made to form a sectional view. Cutting planes are made up of a long dash, followed by two short dashes that are slightly thicker than a phantom line.

Phantom Lines

A line that indicates the alternate positions of a movable feature, repeated details, or material that will be removed during a stage of the manufacturing process. A phantom line consists of alternating long dashes with two short dashes in between.

Hidden Line

A line used to define a part feature that is not visible in a specific view. Hidden lines consist of a series of short dashes.

Break Line

A line used to define the boundary of an imaginary broken-out section or to shorten dimensions that are excessively long. Break lines are wavy and irregular.

Dimension Line

A line used to define the measurement of a part feature. Dimension lines consist of a solid line with arrows at both ends.

Center Line

A line used to define the midpoint of a cylindrical or symmetrical feature or part. Center lines consist of alternating long and short dashes.

Object Line

A line used to define the shape and size of a part feature and represent the visible edges of the part. Object lines are solid.

Section Line

A line used to identify the imaginary cut portion of a part in a section view. Section lines appear as a series of diagonal lines drawn close together at a 45-degree angle.

Extension Lines

A line used to visually connect the ends of a dimension line to the relevant feature on a part. Extension lines are solid and drawn perpendicular to the dimension line.

Workholding

A method or device for securing a workpiece for a machining operation. Workholding can include chucks, vises, and bolts.

Decimals

A number representing a portion of a whole. Decimals are indicated by values to the right of a decimal point.

Ratio

A numerical expression representing a part of a larger whole or proportion. A ratio consists of two numbers separated by a colon.

Fractions

A numerical expression representing a part of a larger whole. Fractions appear as one number over the other with a horizontal line or slash between them.

Half Section

A section view in which an imaginary cut is made through the part and half of that cut is presented cut-side up. Symmetrical parts often contain half sections.

Full Section

A section view in which the part is cut entirely in half. The right side is removed and presented cut-side up.

Offset Section

A section view resulting from an imagined cut resulting from a line that has segments which turn at 90 degrees, with both end segments going in the same direction. Offset sections allows features to be shown that don't occur in a straight line.

Broken-Out Section

A section view resulting from an imagined cut that removes a small portion of the part exterior to reveal the features beneath. Broken-out sections are used to highlight small details.

Removed Section

A section view resulting from an imagined cut that removes and rotates a slice taken from the middle of a part feature. Removed sections are sometimes used to show an enlarged area of a part too small to be illustrated clearly on the original view.

Revolved Section

A section view resulting from an imagined cut that separates the middle of the part feature and rotates a slice taken from that cut in place. Revolved sections have section lines and show the true shape of a part.

T-Slot Nut

A specially-shaped fastener typically used with a threaded clamp to secure a position. T-slot nuts enable engineers to place fixture components anywhere along the component where the T-slot runs.

Leader Line

A thin line ending in an arrow or dot used to indicate a part feature. Leader lines may be used when there are space limitations in a view.

Functionally Complex

Able to correctly and efficiently perform a specific task. The functional complexity of blueprint drawings allows for the creation of parts that can perform tasks immediately after being built.

What is indicated by a feature with a tighter tolerance than the rest of a print's dimensions? The tightest tolerance on a blueprint indicates a feature that:

Affects a part's fit or function.

Views

All the lines that illustrate the shape of the part. A blueprint often contains multiple views to convey all of a part's design elements.

Tolerances

An acceptable variation or deviation from a given dimension or geometry. Tolerances indicate the allowable difference between a physical feature and its intended design.

Notes

An additional instruction or general comment added to a blueprint. Notes contain information about the material, finish, tooling, tolerances, and other miscellaneous information.

What should be included in a change block? A change block should include:

Any revisions, as well as the dates they were made.

Oblique

At a slanted angle. Oblique angles are not parallel or perpendicular to a surface or line.

Which of the following shows a straight view of an angled side?

Auxiliary view

What view is this?

Broken-out section

What type of lines are used to indicate the midpoint of a cylindrical part or feature?

Center lines

Which type of line is indicated in the drawing?

Dimension line

What line is this?

Extension Line

Perpendicular

Forming a 90° angle with another plane or object. Perpendicular lines form corners like those found on a piece of paper.

Geometric Dimensioning And Tolerancing

GD&T. An international standard for communicating instructions about the design and manufacturing of parts. Geometric dimensioning & tolerancing uses universal symbols and emphasizes the function of the part.

What view is this?

Half section

Three-Dimensional

Having or appearing to have length, breadth, and depth. Three-dimensional drawings show an object's shape better than flat drawings.

What line is this?

Hidden Line

International Organization For Standardization

ISO. An organization that establishes documented standards, rules, and guidelines to ensure that products, processes, and services are fit for their purpose. Along with American Society of Mechanical Engineers, ISO provides written standardization for blueprints.

What line is this?

Leader Line

What is a purpose of a center line on a blueprint?

Locates the center of a cylindrical part or feature.

In addition to the drawing and the dimensions, what other basic element is found in all blueprints?

Notes

What line is this?

Object line

What view is this?

Offset section

Which of the following statements about dimensions on a blueprint is true? Blueprint dimensions are:

Often given in decimals rather than fractions.

What type of view presents two-dimensional drawings of each side of a part?

Orthographic

What type of line indicates an alternate position of a movable part?

Phantom line

What is a revolved section view? A revolved section view:

Removes a thin slice of a part and rotates it ninety degrees.

Deburring

Removing sharp projections left on a workpiece after a machining or grinding operation. Deburring is often done by hand or by robot using coated abrasives.

How does a hidden line function in a blueprint? A hidden line:

Represents an edge obscured by another feature of the part.

What view is this?

Revolved section

Parallel

Running equidistant from each other at all points. Parallel means never intersecting.

What describes the relationship between a part's drawing and the actual part size?

Scale

What type of line helps a viewer visualize an imagined slice in a part where material has been cut out?

Section line

Crosshatch

Sets of parallel lines that intersect to form a pattern. Cross hatch patterns are often used in blueprint design.

Third-Angle Projection

The American standard for engineering drawings. In third-angle projection, the front view is under the top view.

First-Angle Projection

The European standard for engineering drawings. In first-angle projection, the top view is under the front view.

Title Block

The area of a blueprint containing information such as company name, part name, part number, designer, scale, and material. Title blocks are unique to each manufacturer.

Change Block

The area of the blueprint indicating any changes or revisions made to the part views or dimensions. Change blocks should contain every revision, as well as the dates in which those revisions were made.

What should be included in a title block? A title block should include:

The date of the drawing and part number.

Surface Finishes

The degree of smoothness of a part's exterior after manufacturing. Surface-finish quality will usually be specified on a manufacturing print.

Dimensions

The desired measurement of a feature on a part. A dimension is listed as a unit.

How are part dimensions found on a blueprint?

The dimensions are listed with the features they indicate.

Inspection

The examination of a part during or after its creation to confirm that it adheres to specifications. During inspection, defects may be identified and corrected.

Throat Depth

The measurement determined by the thickness of a material and the dimensions allowable for simple machines like a T-slot bolt. Throat depth is an important measurement in determining the dimensions of a T-slot.

Head Width

The measurement of the distance across the flat top of a fastener. Head width is an important measurement in determining the dimensions of a T-slot.

Head Depth

The measurement of the flat top of a fastener from top to bottom. Head depth is an important measurement in determining the dimensions of a T-slot.

Throat Width

The measurement of the threaded neck of a T-slot bolt from side to side. Throat width is an important measurement in determining the dimensions of a T-slot.

Dimensioning

The process of determining the desired measurement of a feature on a part. The ideal dimensions for a part can never be met, requiring the addition of tolerances.

Scale

The relationship between the size of the drawing on the print and the actual finished part size. The scale for a part drawing is usually listed in the title block.

What do the dimensions on a print indicate?

The size of a part or feature.

Sum

The total amount resulting from adding two or more numbers together. Sums are useful when showing the total of other dimensions given on a print.

How is the importance of a specific feature indicated in a blueprint? The importance of a specific part feature is indicated by:

Tighter tolerances.

Which section of a print lists the company name, part name, part number, and the date the drawing was made?

Title block

Which of the following indicates the allowable deviation of a measurement?

Tolerance

Which type of dimension is followed by the letter "X" or the word "PLACES"?

Typical dimension

What statement about blueprints is true? Blueprints illustrate all the design elements of a part using:

Views

Windings

Wire wrapped around a core or into a coil that is used to conduct current. Windings form electromagnets and magnetic fields in motors and other devices.

Which of the following symbolizes a typical dimension?

X