SHOP SKETCHING

A COURSE OF PROBLEMS FOR MECHANICAL DRAWING STUDENTS

By RALPH F. WINDOES

Supervisor of Manual Arts, Rock Island, 111. Author of "Architectural Drawing for Secondary Schools," "Cedar Chests: How to Make Them," "Stories of the Industries," etc.

THE BRUCE PUBLISHING COMPANY MILWAUKEE, WIS.

CONTENTS

Page

Preface 5

General Statement - 7 Problems in Sketching -

The Perspective Protractor - 26

The Circle in Perspective 30

Sketching on Cross Section Paper - - 54

Supplementary Problems 56

416030

PREFACE

THE ability to rapidly make freehand sketches, either in perspective or orthographic, is one of the essential accomplishments of all good draftsmen. By this means they may interpret to persons not informed how to read working drawings. With this ability draftsmen are able to rapidly sketch some detail of a machine or a broken part too largo to carry to the drafting room, where a working draw- ing can be made from the sketch. A study of sketch- ing is one of the quickest means of learning how to read working drawings, as it does not involve tho ability to use the drafting instruments skillfully. These are only a few of the many advantages that are well known and appreciated by teachers — ad- vantages that have given shop sketching an important place in every mechanical drawing course.

This text presents a carefully arranged and thoroughly tested course of problems in shop sketch- ing which will leave with the average student com- pleting it the ability to make sketches from objects; perspective sketches from working drawings; and the ability to accurately read working drawings. It

should be given in the last half of the first year's work, or in the second year. Since so many students drop out of school after the first year, the latter part of that year is recommended for this work, as nothing can be given that has the practical ad- vantages of shop sketching.

As much theory as possible has been omitted from this course. Technicalities concerning perspec- tive have been carefully explained, simplified, or left to a more advanced course. The one aim has been to impart to the student the knowledge and practice necessary to rapidly make clear and accurate free- hand shop sketches.

The work as arranged can be covered in one half year of five months when the students work forty- five minutes each day of the school week. This should take the average through plate twenty. Other plates have been added to supplement this work, lengthen the course, or to provide work for the more apt stu- dents. These more advanced plates will be of help where the course is used in normal and technical

RALPH P. WINDOES.

General Statement

SHOP SKETCHING. The practical value of free- hand sketching can not be overestimated. It is not too much to say that nothing that can be given in an elementary mechanical drawing course is of more importance to the man who expects to advance in the profession, and the student just beginning his draft- ing course will do well to bear this fact in mind.

Tracers and detailers — mere routine men — may be proficient without the ability to make good, clear, and accurate freehand sketches, but the engineer and the designer must have this ability. The inventor whose time is too valuable to spend in mechanical execution at the drafting board must be able to ma- terialize his thoughts by the means of freehand sketches, which will later be passed on to the drafts- men to execute.

DEFINITIONS. Shop sketches may be of various kinds — as many kinds as there are modes of technical expression, though they are usually in one of two methods — orthographic or working sketches, and

perspective sketches. Any one of the axonometxic projections can be utilized — especially isometric — or cabinet projection may be used. As a general rule, sketches from objects which are to be later drawn up to scale in the regular manner will be made in ortho- graphic. Inventive sketches in either orthographic

Figure 1

SHOP SKETCHING

or perspective, and sketches that are used to explain working drawings to the uninitiated, in perspective.

The camera, when properly focused, shows an ob- ject in true perspective. Figure 1 illustrates a library table from a photograph, Figure 2 is a perspective of the same table, and Figure 3 is its orthographic pro- jection. The close resemblance between the photo- graph and the perspective is very apparent, while the orthographic gives the exact appearance of the top, front, and side views as if each were viewed alone and the others could not be seen. Hence each view in the orthographic shows but two dimensions, while the perspective and photograph show three. This will make it apparent that at least two views are neces- sary in orthographic projection to properly show all three dimensions of length, breadth, and thickness. To the student who has made a study of orthographic projection these statements will come as a review.

As stated before, all of the problems in this course will be made as freehand orthographic or perspective sketches.

Figure 2

DRAWING MATERIALS KEQUIRED. A 2 H pencil, a 4 H pencil, a pencil eraser, paper, drawing board, and thumb tacks are all the materials needed for the drawing work. The paper should have a rather hard surface as the rough surface of the ordinary drawing paper soils too rapidly. The plates are to be made on sheets measuring ll"x 15", which can be cut with- out waste from the standard size of 22"x 30".

The pencils should be sharpened to long, conical points.

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GENERAL STATEMENT

11

MEASURING TOOLS. A two-foot rule and a pair of calipers will be all the measuring tools actually needed for this course, but some additional tools will be of great help, especially when taking measurements of large or complicated machines and parts. These tools are all illustrated in Figure 4 and consist of, in addition to the two-foot rule and calipers, a 12" steel rule or straight edge, plum bob, combination square, and surface gauge.

How TO SKETCH. All work on the drawing board should be done freehand. The T-square and tri- angles may be used in laying out the trimming edge of the plates, but for no other purpose.

The vertical lines should be sketched as illustrated in Figure 5. The fingers grasping the pencil as in writing, control the movement entirely. The side of the hand rests upon the board, also the forearm. The lines are sketched downward, each one about one inch long, where longer lines are desired, and con- nected so as not to overlap. Vertical sketching is a finger movement.

Figure 5

12

SHOP SKETCHING

Horizontal lines are sketched as Figure 6 illus- trates. In this case the third and fourth fingers rest upon the board, as does the forearm. The lines are sketched from left to right, hinging at the wrist. This permits of drawing lines of about one inch and connecting them without laps for longer lines. Re- member, horizontal lines are drawn with a wrist movement, while vertical lines are drawn with a finger movement. Study the illustrations carefully and impress these methods strongly in mind.

References:

Crawshaw and Phillips — "Mechanical Drawing foi

Secondary Schools."

Phillips and Orth — "Mechanical Drawing." French — "Engineering Drawing."

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Problems in Sketching

Plate Layout

PLATE LAYOUT. Tack the paper on the draw- Sketch the border lines in with the 4 H pencil,

ing board near the upper left hand corner. Lay out estimating 1" in from the left hand trimming line,

the trimming edges of the plate, 10"x Uy2", exact, and y2" in from the others. Sketch these lines as

using the T-square and triangles to pencil in these nearly vertical and horizontal as possible. Thia

lines. Now put these tools away as all the rest of much will be done on every plate of the course, and

the work will be freehand. is termed the plate layout.

Plate 1

To draw the first plate, proceed as follows : horizon intersects it at the level of the eye of the

1. Draw the horizon line 2%" dowi1 from the person who is viewino &e perspective drawn.

upper border line, using the 4 II pencil for all of 4. Estimate 1" down from A to B and sketch

this construction work, and estimating all dimensions. the horizontal line through this latter point.

2. Mark points in on this line for the right and 5. Connect A and B with the vanishing points, left vanishing points %" from the vertical border being very sure that the angle of inclination on both lines. sides of AB is the same.

3. Draw a vertical line through the center, and 6. This much of the work has been almost me- establish point A 1%" down from the horizon on thia chanical ; now the student must estimate the distance line. between the vanishing lines that will give him the

Note carefully that the two vanishing points are appearance of faces of a cube, and draw these vertical

on the horizon and the vertical line through the lines. Although the front edge AB of a 1" cube is

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SHOP SKETCHING

1", none of the remaining edges will measure true, since the faces are "foreshortened" as they approach the vanishing points.

7. When these lines have been drawn, connect their upper ends with the vanishing points, as il- lustrated, which will enclose the remaining faces of the cube.

8. If the cube appears as a true perspective, go over its outlines with the 2 H pencil, causing them to stand out from the construction lines. Repeat with the border lines.

9. Complete the plate by putting in the lettering as indicated on the copy, omitting the "instructions" and the dimensions in the circles.

You have now drawn your measuring cube, the basis for all future dimensions in perspective. Re- member the following points :

a. Only the front edge is in its true length.

b. The other lines do not actually measure 1", but they give that appearance.

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Plate 1

18

SHOP SKETCHING

c. This is due to the "foreshortening" of lines as they approach the vanishing points.

d. The level of the eye as you are observing the cube is above the object, hence you see the upper surface. If the level of the eye is below the object,

you see the lower surface. If the level of the eye is neither above nor below, you see neither the upper nor the lower surfaces as Figure 7 illustrates.

e. In this particular kind of perspective which is known as 45 degree perspective, the angles of inclina- tion of similar lines are the same.

Plate 2

1. LAY out this plate as you did Plate 1.

2. Locate point A 5" in from the right hand vertical border line and 2y2" down from the horizon. At this point sketch your measuring cube. The lines to the VPR are estimated the same as those to the VPL which is located on the drawing.

Your problem is to sketch a pile of 108 one -inch cubes, 36 in a layer, three layers high.

3. Draw two cubes directly below your measur- ing cube, remembering that the front edges are in their true length.

4. Connect the edges with VPL.

5. Between the upper converging lines, estimate the faces of six cubes. These will get smaller as they approach the vanishing point.

6. If they appear as cubes, drop vertical lines through the other converging lines.

7. Estimate the angles of inclination toward the right, and repeat.

8. Complete the construction by drawing the lines toward the vanishing points that will give the upper faces of the cubes.

Plate 2

20

SHOP SKETCHING

9. Go over the outlines of the cubes with the 2 H pencil. Omit the "instructions" and the dimen- sions in the circles.

In this problem you have learned how to secure the measurements in perspective for any object, ex- amples of which will follow.

Plate 3

THIS plate represents both an orthographic and a perspective sketch of a small block grooved through the center. It is to be copied freehand, observing the "instructions" on the copy.

1. Lay out the plate as before.

2. Sketch the orthographic, using the 4 H pencil for all of the preliminary work.

3. At point A, draw a measuring cube, and to the right and left of it draw two similar cubes, repre- senting a surface l"x 3"x 3".

4. As the block is 2" high, estimate another inch down from the measuring cube, thus forming your enclosing solid for a block 2"x 3"x 3".

5. Complete the construction of the perspective by drawing the groove through the center, as shown.

6. Go over the outlines of both the orthographic and the perspective with the 2 H pencil, leaving the dimensions on the orthographic light lines.

7. Draw a horizontal through the object for a table line. This will be done on all future perspec- tive drawings.

In this example no vanishing points are to be located, the lines appearing to meet at some dis- tance off the drawing board. Remember that this ia 45 degree perspective and the angles of inclination are the same on both sides of the vertical center.

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Plate 4

THIS plate involves new work in the form of an incompleted orthographic which is to be completed by the student, and lines in perspective other than vertical or horizontal.

1. Lay out the plate.

2. Sketch the orthographic as indicated, com- pleting it where lines are omitted.

3. Draw the "enclosing solid" as a 3" cube.

4. Since the upper edge of the prism comes exactly in the center, estimate 1J4" over from A and connect this point with the bottom edges by the means of slant lines.

5. Complete the plate as previously instructed.

Note that the distance toward the front edge is greater than the same distance toward the far side, since the lines are foreshortened as they approach the vanishing points.

This method may be used to locate any slant lines in perspective. Simply draw verticals and hori- zontals around the slant lines, and estimate the dis- tances on the verticals and horizontals.

The half-inch dimension of the lower edge of the prism must' be estimated on the front vertical edge of the enclosing solid and carried back to the point where needed. All horizontal measurements are estimated on this edge since here they are in their true length.

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Plate 4

24

SHOP SKETCHING

Plate 5

THE new work on this plate involves invisible edges.

1. Lay out the plate.

2. Sketch the orthographic, completing it where lines have been omitted on the copy.

3. Draw the enclosing solid representing a block 21/2/'x 4"x 4". Figure 8 illustrates the constructive lay-out.

4. Sketch the slant lines as you did on the last plate, and complete the left hand and upper surfaces.

5. Copy the invisible edges, noting that they follow the same principles as visible edges.

6. Complete the plate as before.

Invisible edges are seldom used in perspective, since the idea, as with the camera, is to show an

Figure 8

object as it would appear to a spectator. They have been included in this plate as a matter of practice.

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Plate 6

MAKE a working drawing and a perspective from some small straight line, square object assigned by the teacher.

This may be a model joint, a geometrical solid, a block of some kind made for the purpose, or a small piece of furniture such as a footstool or taboret.

Figure 9 gives suggestions as to type.

In drawing the orthographic, sketch the views without taking any measurements. Estimate the measurements and draw the object as near to scale as possible. When the views are finished, put in the dimension lines, then the dimensions, which will be •measured on the object with the rule.

Figure 9

The Perspective Protractor

OUR previous examples have all been in 45 de- gree perspective, that is, the angles of inclination of similar lines have been the same; hence the vanishing points have been the same distance each side of the

vertical touching the horizon at the level of the eye.

It is apparent that if the object is of irregular

shape, much longer than it is wide or high, the 45

degree perspective will not balance up well on the

PROBLEMS IN SKETCHING

27

drawing. Hence we will construct a protractor that will be of help in solving problems involving irregu- lar dimensions.

Figure 10 illustrates the "perspective protractor." It is constructed as follows, using the regular draw- ing instruments:

On a piece of heavy drawing paper or Bristol board, draw the vertical and horizontal center lines. With their intersection as center, draw two circles, one 1" in diameter, and the other 3" in diameter. Divide the larger circle into 24 equal parts, and, by the means of radials, divide the smaller likewise. From the divisions on the smaller circle draw hori- zontal lines to the right and left. From the same divisions on the larger circle draw verticals intersect- ing these horizontals. The intersection of these lines, as shown in the lower half of the construction, will locate points on the curve of the ellipse. The upper half is drawn in the same manner. Use the irregu- lar curve to obtain an accurate figure.

Erase all construction lines within the ellipse, and connect radials to the points located on its curve, as in the upper half of the construction.

Number these points in degrees — starting at the left hand end of the horizontal center line — 15°,

Figure 10

28

SHOP SKETCHING

30°, 45°, etc. With a sharp knife or scissors trim the ellipse carefully.

Figure 11 shows the protractor in use in the drawing of a measuring cube. In this case the left hand edge makes an angle of 30 degrees with the horizontal, hence the right hand must be at 120 degrees since the corner of the cube is a right angle. If the left hand edge had been at 15 degrees, the right hand would have been at 105 degrees, etc. When the object is square on the front corner, there must be 90 degrees between the two faces represent- ing that corner in perspective.

Figure 11

Plate 7

THIS plate involves the use of the perspective protractor.

It is largely a copy plate, but, as far as possible, each student should be assigned a different angle for the perspective,

Place the working drawing nearer the center as your plate will not contain the "instructions."

The sketching of the perspective is like the previ- ous work with the exception of the different angles.

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Note that when the angles of inclination are not the same, the vanishing points will be at different distances from the front corner of the object.

Plate 8

THIS plate requires no orthographic. The prob- lem is to make a perspective from the working sketch given. The long axis is to slope toward the left at 30 degrees on the perspective protractor.

Figure 12 is from a photograph of this joint, which will be of some assistance in sketching the perspective.

Figure 13

The Circle in Perspective

of the previous plates have contained cir- cles or arcs of circles. This feature of the work will now be considered.

All perspective circles are in the form of the ellipse. Figure 13 shows how they are formed on the

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surfaces of a cube. Note carefully that the circles are tangent to the sides of the square faces where the center lines of the squares touch the outlines. This is apparent when the orthographic circle is considered, since the circle is tangent to the square at the same points, Figure 14. Hence, in order to draw circles in perspective, enclose the circles in the orthographic with squares, draw the squares on the perspective with their center lines, and sketch in the perspective circles tangent at these four points. Arcs are treated in the Bame manner, though in this case it is only part of the circle desired. After a little practice in this longer method, the student will be able to sketch in perspective circles and arcs without the aid of the squares.

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Plate 9

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Plate 9

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THIS plate gives practice in the drawing of cir- sketched if the far side face of the cube is put in and

cles and arcs in perspective. It represents three the curve made as directed before. The slight differ-

cylinders, two in the horizontal position, and one in ence ig caused by the foreshortening, the vertical. The instructions are given on the plate.

In the horizontal position, the far side curve is Erase all construction cubes on the finished plate,

not quite parallel with the front, but it is easily leaving the three cylinders with the table line.

Plate 10

THIS plate is an application of the principles holes are sometimes indicated with a note, which

previously learned, the object being a small machine gives the size as well as the method of making them —

part. The two view orthographic and the perspective "drill," "bore," etc.

are both required. Notice that in a working sketch, The student is to copy this plate.

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Plate 11

THIS plate is a further application of the prin- ciples stated. Here more curved surfaces are given. Note that on a perspective, curves that are not sharp, such as filleted corners on a casting, can only be in-

dicated with short, curved lines. The photograph. Figure 15, will he of help when drawing the perspec- tive.

Figure 15

Plate 11

38

SHOP SKETCHING

Plate 12

THIS plate requires the completion of the top view in the orthographic, and a perspective sketch. Figure 16 will be of help in the making of this perspective.

Run the long axis to the left at an angle of 30° on the perspective protractor, since the eccentric is much longer than it is wide.

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Plate 12

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Plate 13

PLATE 13 is a dimensioned perspective of a buffet, from which a two view working sketch is required. This sketch must be dimensioned completely, and in- side construction must be indicated. The student's knowledge of furniture construction will be of help in this; also working drawings of similar types will make good references.

Dimensioned perspectives are not as practical as

working sketches, as they usually consume more time in the making, and it is more difficult to show inside construction with them. But, for small, simple pieces such as washers, bolts, nuts, etc., from which work- ing drawings will be made later, they are sometimes used. And again, they are used occasionally when explaining what is meant by a working drawing to a craftsman who cannot read one.

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Plate 13

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Plate 14

THIS problem requires the sketching of a perspec- tive from the working sketch and the photograph, Figure 17. Make the sketch large enough to balance

the plate well, as it will occupy the plate alone — the orthographic not being required.

Put the dimensions on the perspective.

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Plate 15

THIS problem is similar to the last — a dimen- sioned perspective alone being required.

Note that in the side view, a full section is given on the plate. This is often done in working draw- ings since the inside construction can be more clearly shown.

A section is an imaginary drawing. In this ex- ample, we have imagined that we have cut the piston on a center line through the two wrist pin bearings. We have then removed the front portion and drawn the remainder of the object. Where we have im- agined the saw to have cut the metal, we have drawn light 45 degree lines, known as "section lines."

On future sketching plates from objects show sec- tions if it will make the interior construction any clearer.

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Plate 16

MAKE an orthographic and a perspective sketch of some small object selected by the teacher. Type suggestions are given in Figure 19. Place dimen- sions on the orthographic.

When sketching from objects, take no measure- ments until the views are sketched in. Estimate your proportions to scale as nearly as practical. That is, if you are sketching as nearly full size as possible, try to make your sketches show it in every view and every part. If the object is about 5" long, make it as near 5" as you can estimate, but have the length the same on both the top and front views. Have the width about the same on the top and side views. Have the height about the same on the front and side views.

If you are reducing the object in size on the sketch, show this reduction evenly all the way through.

"When the sketches have been completed — no measurements having been taken — put in the di- mension and extension lines. Put on the arrow heads, and then measure up the object. As each measurement is taken, put it down in its proper dimension line.

When all have been completed, check it over to see if any dimensions have been omitted. Are the three dimensions given for every piece and every part? Are the sizes and centers of holes carefully located, etc.?

Remember that in actual practice if a working drawing is being made from a sketch, the drafts- man must not take the time to go back to the object and measure it for missing dimensions. Every di- mension and every detail must be shown in the sketch.

PROBLEMS IN SKETCHING

47

Figure 19

48 SHOPSKETCHING

Plate 17

FIGURE 20 illustrates the body of a hanger and the front and side views, put on dimension lines, place it is required to make a working sketch from this the dimensions that are given, and estimate the figure. A few dimensions are given — just enough to others. This will give excellent practice in proper- secure correct proportions. The problem is to sketch tion and balance. Check your dimensions carefully.

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SHOP SKETCHING

Plate 18

MAKE a perspective sketch from a piece of furni- ture, but do not dimension it. The cabinet shop projects can be used as models, or the tables, benches, stools, cases, desks, chairs, etc., in the drawing room can be utilized. Each student should be assigned a different project as far as possible. Finish these

perspectives carefully, using the 2 H pencil sharpened to a long point for the finished pencilling stage.

A small amount of shading and graining can bu added to this drawing if desired, but do not spoil the effect with too much. Figure 21 is a good sug- gestion.

PROBLEMS IN SKETCHING

51

Plate 19

FROM a rather small, complicated object such as a valve, carburetor, etc., make a set of detailed orthographic sketches, and an assembly sketch. This may require more than one sheet. If so, number

them Plates 19-A, 19-B, 19-C, etc.

This problem is no more difficult than a single object sketch, it simply requires more sketches. Each part should be drawn up as a single object, but the

Figure 22

52

SHOP SKETCHING

dimensions should be so carefully taken that the de- tailed parts will go together in the assembly with- out a conflict.

Plate 20

THIS final plate of the sketching course is to be drawn up from some machine — a lathe, Figure 23, for example — a gas engine, or any large machine.

The character of the work on this plate will be determined by the amount of time left to devote to it.

Considering the lathe as an example, one student might detail the headstock, another the tailstock, another the tool rest, a fourth the befl, etc., thus com- pleting a set of sketches of a large machine. Or, if time permits, one student could do this alone, other students working on other machines.

If the instructor desires any more perspective sketches, these machines might serve as models for this advanced perspective sketching.

Figure 22 illustrates a few of the objects suggest- ed for this work.

Sketching on Cross-Section Paper

54 SHOPSKETCHING

Sketching on Cross-Section Paper

SOME draftsmen prefer to make their sketches on ments from the object as the views are drawn if the

cross section paper. Figure 24 illustrates such a correct scale is to be maintained,

sketch. This practice has a number of advantages In this course it is recommended that a few of

over the plain paper sketch, especially if the paper the orthographic sketches be made on cross section

used is ruled off in inches and subdivided into paper in order to familiarize the students with this

eights. The vertical and horizontal lines can be procedure.

eights of an inch. The vertical and horizontal lines Another ruled paper that might be of help is the

can be used to guide the pencil in drawing straight isometric paper now on the market. By its use

lines, and the divisions make it easy to sketch to scale. isometrics can be sketched in place of perspectives,

The main difference between this method and the but this is not to be recommended if the ability to

other is that it becomes necessary to take measure- make rapid perspectives is to be acquired.

Figure 24

56 SHOPSKETCHING

Supplementary Problems

THE following plates have been added to sup- longer courses such as might be given in trade or plement the course. They may be used in a number normal schools ; or they may be used to make of ways. They may serve as additional plates for the regular mechanical machine drawings for the ma- more apt students to work upon while the slower are rhine drawing courses, catching up; they may serve as regular plates in

Supplementary Plate 1

This plate represents a test plate to follow regu- be given concerning it, and students should not bo

lar plate 6. It contains less instructive material than allowed to visit with each other nor look at each

the plates preceding, hence the students must use other's work while solving it. more initiative to work it out. No instruction should

GROOVED BLOCK

INSTRUCTIONS

iPL. E: TK THE TOP

PKC. Tl VE /A/

•t—f 2.

_JL..

Supplementary Plate 1

SHOP SKETCHING

Supplementary Plate 2

This plate represents two small machine parts in sketch and a copy of the perspective can be required dimensioned perspective. Its use may be restricted Of each piece, to the drawing of working sketches, or a working

SQILL-

T Bi. QCK

T I

Supplementary Plate 2

60 ^ ;;:-.;' SHOP SKETCHING

Supplementary Plate 3

A working sketch of a special wrench is illus- pulleys, and is sometimes drawn on the object itself

trated on this plate. One feature is a revolved sec- rather than to the side as illustrated, tion — a section at right angles to the center line at

any chosen point to show the shape of the object at The Problem in sketching is to make a perspec-

that point. A revolved section is often used to il- tive from this workinS sketch> or to make a similar

lustrate the shape of the spokes in fly-wheels and sketch from a wrench furnished by the teacher.

SPECIAL WRENCH

It

~H- — — Jr~

-a-"

t±

Supplementary Plate 3

62 SHOP SKETCHING

Supplementary Plate 4

Plate 4 illustrates two working sketches, one of a it being imagined that a part of the object has been

clamp handle such as is sometimes used to tighten broken away in order to show the threads. This is

the tail stock of a wood lathe, and the other an S called a "partial section." wrench. j^ jg SUggested that perspectives be required of

The clamp handle shows screw threads in section, these objects.

VRENCH

CLflMP HANDLE.

Supplementary Plate 4

64 /«\t .''tt'TV *t *•.«,«••'•«'* SHOP SKETCHING

Supplementary Plate 5

Many good problems in sketching can be secured sketches can be made from these perspectives, or

in the wood shop. The footstool and taboret are similar sketches can be made from the working draw-

very familiar objects to most students. Working ings which the cabinet shop will have in abundance.

TfSBOf-lET

FOOTS TOOL.

Supplementary Plate 5

66 SHOPSKETCHING

Supplementary Plate 6

The working sketch of a tumbling shaft bracket piace. An oil hole through both the bearing and the

is a good example of a simple bearing. Notice that bushing allow lubrication for the shaft which moves

on the front view two full circles are represented, back and forth in the bearing, the large one being the hole bored out in the body

of the bracket, and the small one the inside bearing A Perspective from this working sketch is the

suiface of the bushing which is driven or pressed in rc1uired Problem in tnis case'

TUW&UNG SH/1FT BHtfCKCT

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3i-

Supplementary Plate 6

68 SHOPSKETCHING

Supplementary Plate 7

This dimensioned perspective shows a valve yoke of it. Notice the manner of showing the curved such as is used on most types of locomotives. A edges in perspective, working sketch, completely dimensioned, is required

l/W/.l/g YOKE

WROUGHT IRON

Supplementary Plate 7

70 eVec SC'S Vc c ' SHOP SKETCHING

Supplementary Plate 8

This bearing shows two views in full section. such as the cylinder block of a gas engine, may re-

When it is necessary, any number of sections can be quiie at least a dozen sections, taken through various

used to illustrate, clearly, the internal construction parts of the body. of a piece. A large object with many holes inside, A perspective should be made of this project.

CAR

E/4RING FOR u & REEB- C&B3

HOL£

ON

:vr

*

I -i*

ntt.j

(O

^Sj

Hth

Supplementary Plate 8

72 JAt U'' V*' v' ' itt'tS' SHOP SKETCHING

Supplementary Plate 9

It will be very good practice for the student to copy the top view and draw full sections in place of

trace out the meaning of the various dotted lines on the front and side views as they are here given, this working sketch. As his problem, and to test his A perspective from this working drawing will

ability to read working drawings, the student should also prove of value to the student.

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16

Supplementary Plate 9

74 SHOPSKETCHING

Supplementary Plate 10

If a perspective of this bracket is drawn, notice on each side of the center line are the same. There

that there are two bearings, the one to the left being is always one dimension which covers the entire

the same distance from the center line that the one length of the finished piece. The dimension 32 1/2"

to the right is drawn. This is often done in work- represents it here, and there is no arrow head on its

ing drawings when the object is long, and the parts left hand end.

/v?O TiON QOD K

ran /•„ BOL.TS

r

i-

1r

6 — — 3

.5 .

i

T

v

VV/?0_r IRON 022^

-/ '

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Supplementary Plate 10

76 SHOP SKETCHING

Supplementary Plate 11

The last three plates represent projects of interest The ability to make such sketches will be appreciated

to agricultural and architectural students. by the farmer who very often is called upon to ex-

In the first the perspective of a watering trough plain some part of his farm equipment to another

is given. The principal dimensions are attached. person who is to build it for him.

CONCRETE WATERING

Supplementary Plate 11

78 SHOPSKETCHING

Supplementary Plate 12

The perspective of an ordinary window frame is head, stile, and sill, dimensioning the parts in the

shown en this plate. regular manner.

The student should draw sections through the

WINDOW

IN

Supplementary Plate 12

80 SHOP SKETCHING

Supplementary Plate 13

The problem presented on this plate is an inter- wishes to duplicate on his farm, it will be a very use-

esting one to the student of agriculture. After solv- fuj procedure for the student to measure up and

ing it and putting on its principal dimensions, he sketch the hog pen in such shape that the building

sh-uld have acquired the ability to make working can be built from his sketches without the need of

sketches of simple structures of this type. If a further reference to the existing building, neighbor owns a hog pen which the student's father

CHICKEN HOUSE

~' ~ '

INSTRUCTIONS £i l-aONT flfiJO f} 3 1 'PC i/ff.W OF THIS CH/CK£".*i ^OU3£. Afo O/M-

r

Supplementary Plate 13

INDEX

Page

Angle of Inclination 14

Hoard 8

Calipers 11

Circle in Perspective 30

Contents 3

Cross-Section Paper 54

Definitions 7

Drawing Materials 8

Enclosing Solid 20

Erasers 8

Foreshortening 16

Forty-five degree Perspective 18

Horizon Line 14

Horizontal Sketching 12

How to Sketch 11

Index 83

Inventive Sketches 7

Measuring Tools 11

Paper 8

Pencils 8

Perspective Protractor 26

Plate Layout 14

Plate 1 14

Plate 2 18

Plate 3 20

Plate 4 22

Plate 5 24

Plate 6 26

Plate 7 28

Plate 8 30

Plate 9 34

Plate 10 34

Plate 11 36

Plate 12 : 38

Page

Plate 13 40

Plate 14 42

Plate 15 44

Plate 1<3 46

Plate 17 48

Plate 18 50

Plate 19 51

Plate 20 52

Plumb Bob 11

Preface 5

References . . . '. 12

Rule 11

Section 44

Shop Sketching 7

Supplementary Plate 1 56

Supplementary Plate 2 58

Supplementary Plate 3 60

Supplementary Plate 4 62

Supplementary Plate 5 64

Supplementary Plate 6 66

Supplementary Plate 7 6S

Supplementary Plate 8 70

Supplementary Plate 9 72

Supplementary Plate 10 74

Supplementary Plate 11 76

Supplementary Plate 12 78

Supplementary Plate 13 80

Square 11

Surface Gauge 11

Table Line 20

Test Plate 56

Vanishing Points 14

Vertical Sketching 11

Working Sketches 7

f

YC 19717

4 ! 6030

UNIVERSITY OF CAUFORNIA LIBRARY