Hammer's Blueprint Reading Basics

By Charles Gillis and Warren Hammer

Overview

       Warren Hammer’s Blueprint Reading Basics has been a bestselling classic for nearly two decades, revered for its ease of understanding and for giving readers opportunities to practice what they learned. With this historic revision, new author Charles Gillis has updated the entire package, replacing ALL figures with CAD-generated artwork, adding new illustrations, representing metric drawing practices alongside English, and including content from drawing standards such as Dimensioning and Tolerancing, Engineering Drawing Practices, Welding Symbols, Orthographic and Pictorial Views, Surface Texture, Undimensioned Drawings, and Types and Applications of Engineering Drawings, among others.
       Material has been rearranged for better presentation and an improved reader experience. Chapters on views, dimensions, surface finish, threads, and gears have been expanded, while new material on splines and cam prints has been added. Brand new chapters covering welding symbols and welded parts, sheet metal parts, and cast, forged, and molded plastic parts will be of particular interest to readers working with these processes. 
       Each chapter contains a thorough explanation of the topic at hand, accompanied by detailed professional drawings, review questions, and corresponding worksheets, making this an ideal reference for students and instructors alike, and a must-have for mechanical engineers, draftspeople, inspectors, machinists, and students learning the manufacturers trades. This groundbreaking work now features a broad presentation of metric drawing standards and internationally recognized symbols, making it a truly global reference.

An Instructor’s Resource (sold separately) includes:

• Over 600 PowerPoint presentation slides for using the book in the classroom. The arrangement mirrors the book and can be customized by instructors.
• Blueprint Reading Course Recommended Syllabus and Lesson Plans, to be customized to suit each instructor’s needs.
• PDFs of Selected Figures and Tables.
• PDFs for Review Questions and Answers.
• PDFs for Worksheet Problems and Solutions.

• Language: English
• Publisher: Industrial Press, Inc.
• Release date: Aug 21, 2023
• ISBN: 9780831194321

Charles Gillis

Charles Gillis has over 20 years of machine design experience.  He is a mechanical design engineer for the Proctor & Gamble Company.  For the last 6 years, he has taught WPI’s Geometric Dimensioning & Tolerancing courses.  He is also a contributing author to Machine Designer’s Reference, published by Industrial Press.

Book preview

Preface

Blueprints are manufacturing instructions and generally contain a drawing, dimensions, and notes. Blueprints originate in the engineering department and give the manufacturing department all the information that is needed to manufacture a product. The term blueprint originated years ago when these prints had a blue background and white lines. Today, most prints have a white background and black lines. They are still, however, often called blueprints. Many organizations do not use the term blueprint and instead use such names as prints, drawings, or manufacturing prints. The term blueprint is, however, generally well understood. Architectural blueprints are plans to construct buildings. The term is also commonly used to describe a plan to accomplish a goal. In the text, a blueprint will be called a print or a manufacturing print.

The most important part of a print is the drawing, and the most important part of print reading is the ability to visualize that drawing. Since this ability to form a mental picture of the drawing is the most difficult part of print reading for many students, Blueprint Reading Basics reviews this subject in great detail, using many illustrations and examples, as well as thoroughly reviewing all other aspects of print reading.

Each chapter of Blueprint Reading Basics covers one subject and includes an introduction, a detailed review of the subject, illustrations, review questions, and worksheets. In order to concentrate on print reading, discussions of related subjects such as mathematics, engineering, drafting techniques, and machine shop practices are kept to a minimum. A thorough knowledge of these subjects is desirable, but such knowledge is not essential to learning to read prints. There are also no exercises that require special skills such as freehand drawing; such skills are useful, but they are not needed to interpret prints.

Industry practices, industry standards, and copies of industrial prints are included throughout the text. The resulting combination of print reading theory and industry applications produces a book that is oriented toward practical concerns.

Blueprint Reading Basics is intended for classroom use in a one- or two-semester course in print reading; it can also be used for self-study. Because of its easy-to-understand writing style and use of many illustrations, prints, and examples, Blueprint Reading Basics can be used profitably by anyone who must learn to read prints.

Worksheets

Each chapter has one or more worksheets that provide basic and practical training. Most of the worksheets were designed as teaching aids, but there are also many worksheets that include industrial prints. This combination of basic teaching exercises along with industrial prints provides a practical approach to print reading. Worksheet questions are short and specific. There should be little or no confusion about the meaning of a question. Questions require short and specific answers.

It must be noted that the exercises were designed as teaching aids and there are a great number of questions that require calculating dimensions. This method has proved to be the most effective way of learning how to read prints. On the other hand, prints that are used in industry are dimensioned, so calculations are not required. When working with industrial prints, use the data that are shown on the print. Do not make calculations unless they are necessary.

Worksheet Guides

Some of the worksheets have guides that either establish general rules for all worksheets or help answer specific questions. All worksheet guides should be reviewed. In some cases, similar guides are shown on more than one worksheet. Some students may not have a need for some of the guides, while other students will find them very helpful. The guides are located throughout the text as they apply to worksheets. This arrangement makes them more meaningful and easier to remember instead of having them all located at the beginning of the book.

When reviewing worksheets, it is important to get the correct answer, but it is also important to understand how the answer was obtained. Knowledge of how answers are obtained will build a base for understanding future worksheets as they become more complicated.

Industry Standards

Industry standards for such things as threads and gears are referred to throughout the text. When a print refers to an item that has a standard, the entire standard applies. As an example, in a print that specifies a 1/4-20 UNC-2A thread, UN stands for Unified, and it has an industry standard. The standard specifies all data pertaining to Unified threads, such as maximum and minimum diameters. These details therefore do not have to appear on a print. Industry standards are a very important part of manufacturing and keep prints uncluttered.

Third Edition

Blueprint Reading Basics has been a popular textbook in the academic and industrial world for many years. The third edition concludes over ten years of classroom and industrial experience. Many instructors and students have made worthwhile contributions to make it a practical text. The most effective learning tools in the text are the worksheets.

After reviewing the text on a specific subject, the worksheets provide effective and practical means of review and make the subject easier to understand. This method has proved to be very effective in the learning process. The third edition has many new and rearranged worksheets to make this process easier to follow. Many of the worksheets have been revised so they can be completed after studying one subject. This means some of the worksheets can be reviewed before studying the entire chapter. As an example, in Chapter 3, Worksheet 3-2 can be completed after studying The Lines of Manufacturing Prints. Worksheets are practical and effective. Worksheets work.

Fourth Edition

Hammer’s Blueprint Reading Basics has been a favorite of beginners and educators for decades. It is praised for its complete coverage of the basics, for its ease of understanding, and for giving learners opportunities to practice what they have learned.

The fourth edition presented an opportunity to modernize and expand the text to make it useful to students in the modern workforce. It also presented a challenge to ensure it retained the qualities of the original: simple, direct, down-to-earth, and friendly.

Several chapters have been expanded and material has been re-arranged for better presentation. Chapter 3 focuses on engineering drawing practices and the total print. Chapter 4 contains additional types of views and drawing techniques. Chapters 5 and 6 expand the treatment of dimensioning and tolerancing techniques with more illustrated examples. Geometric Dimensioning & Tolerancing has been moved to follow in Chapter 7, and been re-written for a better flow. Chapters on surface texture and treatments, threads, and gears have all been expanded. New material has been added to existing chapters covering splines and cam prints. New chapters have been added covering cast, forged, and molded plastic prints; and welded and sheet metal prints.

The figures and prints in the fourth edition contain a combination of both millimeter and inch values, recognizing the fact that both units of measure are common in industry. You are likely in your career to encounter both units on prints. Metric drawings have been given a full and equal presentation along with English drawings.

Engineering prints made to current practices rely much more on symbols than English words to convey design requirements so anyone across the globe can understand them, regardless of where they were made. These symbols and drawing standards allow all manufacturing professionals to successfully interpret the meaning of prints without subjectivity or ambiguity. The fourth edition presents symbols and standards currently used and commonly encountered on prints while recognizing students are still likely to encounter prints made according to prior practices.

All the hand-drawn figures and prints of the previous edition have been replaced with CAD-generated figures to give the reader a clear and professional appearing textbook. Except for the sample prints donated from industry, all the figures have been replaced. To present the expanded content, the number of figures has been increased by over 50 percent. Worksheets have been added and updated to give the student broad practice on all textbook concepts.

Introduction

The Manufacturing Cycle

The Manufacturing Print

Review Questions

Worksheets

Introduction

Blueprints document the requirements of manufactured parts. These requirements include geometric requirements: the intended size, shape, dimensions, and amount of variation that is acceptable. Requirements also include information like material, finish, special assembly and processing instructions, and inspection instructions. They originate in the engineering department and give all the downstream users the information that is needed to make the part. Blueprints transform ideas into products and communicate information among all parties involved, such as customers, sales, designers, drafters, purchasers, routers, machinists, machine operators, assemblers, and inspectors.

The term blueprint originated years ago when prints were blue. Prints had blue backgrounds and white lines. Today most prints are white and have black lines, but they are still sometimes called blueprints. Other more common names are prints, drawings, specifications, manufacturing prints, engineering drawings, dimensional specifications, and industrial prints.

The three basic elements of a manufacturing print are the drawing, dimensions, and notes. Prints contain all the information that is needed to make a finished product, either explicitly or referenced in associated documents. A finished product may be anything from a simple part to a complex assembly. Quantities of parts to be made may range from one to millions. Manufacturing organizations range in size from small machine shops to large industrial corporations and often involve suppliers and service providers outside the manufacturer’s organization. In all cases, prints provide the common definition of the finished product requirements around which all manufacturing activities are arranged.

Industrial prints use an orderly and systematic graphic language. They present data in an easy-to-understand form. Prints are rather easy to read, if the principles are studied one step at a time. Print reading is similar to mathematics; it takes work and time to learn at the beginning. Once learned, it becomes easy; and once learned, it is not forgotten. Print reading is an essential skill for working in any manufacturing capacity.

The purpose of this chapter is to provide a broad overview of manufacturing prints. Additional information will be presented on each item in subsequent chapters.

Before starting to study print reading, it is recommended that you obtain a 1-inch angle bracket, similar to the one shown in Figure 1-1. The bracket will serve as a helpful visual aid. A comparison between the actual bracket and all the figures in Chapters 1 and 2 will make it much easier to visualize all the drawings.

The prints in this book contain a combination of both millimeter and inch values, recognizing the fact that both units of measure are common in industry. You are likely in your career to encounter both metric and English prints.

The Manufacturing Cycle

The manufacturing cycle revolves around prints. Ideas are transformed to manufacturing prints, and they are used to manufacture finished products. Finished products are distributed and sold to customers. As products are used, changes and improvements are recommended. Worthwhile improvements are adopted, and drawings are changed accordingly. Improved products are manufactured, and then they are sold to customers. This is a continuous cycle, as shown in Figure 1-2.

The Manufacturing Print

Manufacturing prints have three basic elements: a drawing, dimensions, and notes; see Figure 1-1. These items will be reviewed throughout the book. A brief description follows so a good overall picture can be formed early in the study.

Figure 1-1 Drawing, dimensions, and notes

Drawing

The main part of a manufacturing print is the drawing; see Figure 1-3. The drawing shows the exact shape of a part. Drawings may contain a single view of the part or several views. They have as many views as necessary to visualize the part. An example drawing composed of three views labeled top, front, and side is shown in Figure 1-4. Drawings with multiple views are arranged following a system of straight-line projections between views, as shown in Figure 1-5.

Figure 1-2 The manufacturing cycle revolves around prints.

Figure 1-3 The main part of a print: the drawing

Figure 1-4 Three views

Figure 1-5 Views are straight-line projections of the part.

Dimensions

Every feature of every part has a dimension, and each dimension includes a tolerance. The dimensions describe the exact geometry of the intended part, and tolerances indicate how closely manufacturing needs to match the dimensions to produce parts that are considered acceptable; see Figure 1-6.

Figure 1-6 Dimensions indicate the exact size and shape requirements for the part.

Notes

Notes include such things as material, finish, surface treatments, and any other information that is needed to manufacture the part; see Figure 1-1 again.

Review Questions

1. What is used to communicate manufacturing instructions?

2. Where do manufacturing drawings originate?

3. What does the manufacturing cycle revolve around?

4. Lines on prints are generally what color?

5. Name two other names for prints.

6. What are the three basic elements of manufacturing prints?

7. What is the main part of a print?

8. What do dimensions specify?

9. What unit of measurement is used on metric prints?

10. What unit of measurement is used on English prints?

1. _______________ Type of view; see Figure 1-4

2. _______________ Type of view; see Figure 1-4

3. _______________ Type of view; see Figure 1-4

4. _______________ 1/16 is a, see Figure 1-6

5. _______________ What indicates exact size and shape requirements? See Figure 1-6

6. _______________ Number of views

7. _______________ Number of dimensions

8. _______________ Number of holes

9. _______________ Diameter of holes

10. __________________Material

11. __________________Finish

12. __________________Name

13. __________________Drawing number

14. __________________Tolerances

15. __________________Burrs are to be

16. __________________How wide is the side view?

Worksheet 1-1

1. _______________ Type of view

2. _______________ Type of view

3. _______________ Number of views

4. _______________ Number of hole notes

5. _______________ Number of Ø6.6 holes

6. _______________ Number of Ø8.5 holes

7. _______________ Material

8. _______________ Finish

9. _______________ Name

10. _______________ Drawing number

11. _______________ Weight

12. _______________ Scale

13. _______________ Revision

14. _______________ Sheet

15. _______________ View label

16. _______________ Does the print contain all the information that is needed to make the part?

Worksheet 1-3

1. _______________ Type of view

2. _______________ Type of view

3. _______________ Type of view

4. _______________ .188 is a

5. _______________ Number of views

6. _______________ Number of holes

7. _______________ Diameter of holes

8. _______________ Burrs are to be

9. _______________ Material

10. _______________ Finish

11. _______________ Name

12. _______________ Drawing number

The three most important parts of a print are:

13. _______________

14. _______________

15. _______________

16. _______________ Do prints show all the information that is needed to make the part?

Worksheet 1-3

Introduction

Types of Drawings

Projections

Projection Systems

Visualization

Interpretation

Review Questions

Worksheets

Introduction

Print reading is the process of analyzing a print to obtain information and involves two activities: visualization and interpretation. Visualization is the ability to envision, or see, the shape of a three-dimensional object from the various views shown on a two-dimensional print. Learning the principles of projection will help you gain the ability to visualize objects from views shown on a print.

A machinist must visualize a part from a print before it can be made. After a part is made, an inspector generally checks the part to see if it conforms to the drawing. The inspector must form a mental picture of the part from the drawing in order to inspect the part.

The interpretation of lines, symbols, dimensions, notes, and other information on a print is the other important part of print reading. Many of the common symbols used on prints are presented and explained. Numerous examples and opportunities to test your knowledge are presented in the chapters that follow.

In this chapter, you will learn how to form a mental picture of a typical manufactured part. This will be accomplished by reviewing the following items:

▪ Types of drawings

▪ Projections

▪ Visualization

Types of Drawings

Drawings are either artistic or technical. Artistic drawings may be abstract or realistic and may depict intangible concepts, such as love, or concrete objects, such as a landscape. Perspective projection is common for realistic drawings. Interpretation is subjective, and few standards exist for artists to follow. There are many good art books at your local library.

This book is about technical drawings. Technical drawings represent concrete objects to be built or constructed in a realistic manner, using parallel projections according to standards designed to ensure there is only one possible interpretation. Subjectivity and ambiguity are the enemy of successful communication using technical drawings.

Technical drawings are used for civil engineering, surveying, construction, and architecture. Although many conventions are the same across all types of technical drawings, within each of these fields different standards are followed, and different objects are likely to be illustrated. This book is about technical drawings used for engineering and manufacturing purposes.

Projections

Drawings are two-dimensional representations of three-dimensional parts to be built. Creating a two-dimensional representation of a three-dimensional part requires the drafter to project the part onto a two-dimensional surface. There are many methods of projection used for various purposes. The process of projection can be illustrated using four concepts: the object being projected, the plane of projection, projection lines, and the observer’s viewpoint, as shown in Figure 2-1.

Figure 2-1 Object, plane of projection, projection lines, viewpoint

The projection plane sits between the observer’s viewpoint and the object being projected, and this represents the two-dimensional drawing. Projection lines are straight lines that all begin at the observer’s viewpoint and end on points of interest of the object. Along their path, they intersect the plane of projection.

Your Shadow

The process of projection is not as strange as it might sound; we all experience projection in our daily lives. Your shadow cast by the sun is a two-dimensional projection of a three-dimensional object: you. When you project a shadow, projection lines originate at the sun, and you sit between the sun and the plane of projection; see Figure 2-2.

Figure 2-2 Your shadow is a projection.

Perspective

The perspective projection uses an observer’s viewpoint located at a finite distance from the projection plane and the object. No projection line is parallel to any other projection line.

A drawing made using the perspective projection is shown in Figure 2-3.

Note that the edges on the object that are parallel to one another do not appear parallel on the perspective projection. Detail on the object that is farther away appears smaller. The perspective projection approximates the appearance of an object as observed by the eye.

Figure 2-3 Perspective

Parallel

Parallel projection uses an observer’s viewpoint located an infinite distance from the object. Stated differently, all projection lines are parallel to one another. This has the effect that a line on the object is projected into a line on the projection plane. Parallel lines on the object become parallel on the projection. The midpoint of a line on the object is projected to the midpoint of the line of the projection.

There are several types of parallel projections, each following slightly different rules. The main types are orthographic projection and oblique projection; see Figure 2-4.

In oblique projection, the projection lines cross the projection plane at a nonperpendicular angle. Oblique projection includes the subtypes cabinet, cavalier, and military; see Figure 2-4. Oblique projections were common as recently as the nineteenth century in technical, architectural, and military depictions. Modern blueprints use orthographic, not oblique, projection.

Figure 2-4 Orthographic versus oblique projections

Orthographic Projections

In an orthographic projection, the projection lines are perpendicular to the projection plane. There are several subtypes of orthographic projections:

▪ Single-view, or axonometric, projection:

– Isometric

– Dimetric

– Trimetric

▪ Multiview projection:

– Third-angle projection

– First-angle projection

Figure 2-5 is an orthographic projection of the L-bracket, observed from the front. The front surface of the object has been shaded to identify it. The same type of projection for the top view is shown in Figure 2-6, and the side view is shown in Figure 2-7.

Figure 2-5 A front-view projection of an isometric drawing

Figure 2-6 A top-view projection of an isometric drawing

Figure 2-7 A side-view projection of an isometric drawing

Single-View Projections

Figure 2-8 illustrates three different ways of making a single-view orthographic projection of the L-bracket. In each, the observer views the object from a standard viewpoint defined by the angles shown. Though these viewpoints were standardized based on the manual drafting techniques used to create them, CAD projections of objects from one viewpoint are just as easy to make