ECHANICAL 
 DRAWING 
 
 SCHOOLS 
 
 C.C.LEEDS 
 
 D.VAJV NOSTRAND COMPANY 
 
 PUBLISHERS 
 
 MEW YORK 
 
LIBRARY 
 
 OF I II I 
 
 UNIVERSITY OF CALIFORNIA. 
 
 Class 
 
The D. Van Nostrand Company 
 
 intend this book to be sold to the Public 
 at the advertised price, and supply it to 
 the Trade on terms which will not allow 
 of reduction. 
 
Carnegie {Technical Schools cyt Boohs 
 
 MECHANICAL DRAWING 
 
 FOR 
 
 TRADE SCHOOLS 
 
 BY 
 
 CHARLES C. LEEDS 
 
 Assistant to Head of School for 
 
 Apprentices and Journeymen 
 
 Carnegie Technical Schools 
 
 HIGH-SCHOOL EDITION 
 
 OF THE 
 
 UNIVERSITY 
 
 OF 
 
 NEW YORK 
 
 D. VAN NOSTRAND COMPANY 
 
 1908 
 
& 
 
 COPYRIGHT, 1908 
 BY 
 
 D. VAN NOSTRAND COMPANY 
 
 THE 
 
 VAN NOSTRAND PRESS 
 NEW YORK 
 
OF THE 
 
 UNIVERSITY 
 
 OF 
 
 PREFACE. 
 
 THE purpose of this book is twofold: To prepare High-school 
 students to pass the examinations required for admission to Technical 
 Schools, and to enable the High-school graduate to earn his living 
 as a tracer or detail draftsman. 
 
 The author's conviction that the use of models serves to develop 
 copyists and often tends to stunt or destroy a draftsman's creative 
 faculties, has led him to discard entirely the use of models in teaching 
 Mechanical Drawing, and he feels that it will be obvious, even to the 
 casual observer, that when a student has been given a model of his 
 subject for the drawing lesson, little or no effort will be required from 
 his imagination. 
 
 The model stands before his eyes, complete; no effort on his part 
 is necessary. When the student, however, is given a blue-print or 
 drawing of the subject, difficulties arise at every step. In order to under- 
 stand the meaning of the views shown, he has to study the subject care- 
 fully and grasp the meaning of each line. In short, he has to think. 
 To form a MENTAL PICTURE of the piece illustrated is more difficult 
 than mere copying; it is also more beneficial. 
 
 That faculty of imagining, that mental picturing so necessary 10 
 the good draftsman or designer, can be developed within every stu- 
 dent. It is a part of his development, just as an understanding of the 
 meaning (either definite or conventional) of each line of a drawing 
 is a part of his development. 
 
 Convinced of this fact, the author has arranged these lessons in a 
 manner which he believes will attract and hold the attention of the 
 student. Each lesson will guide the student by easy steps, illustrate 
 some fundamental point in Mechanical Drawing, and work as a whole 
 towards the development of the creative draftsman. 
 
 The results obtained by the author at the Carnegie Technical 
 Schools, through this mode of teaching, justify him in this belief, and 
 prompt him to place within reach of every one interested in the sub- 
 ject this simple treatise, which he hopes will be as fruitful in the hands 
 of others as it has been in his. 
 
 CHARLES C. LEEDS. 
 March 15, 1908. 
 
 192820 
 
UNIVERSITY 
 
 OF 
 
 LESSON No. i. 
 
 PENCILS. It is very important that the student of Mechanical 
 Drawing should have good tools to work with, and just as important 
 that he should learn to take good care of them that they may be always 
 ready for use. No tool is more used in mechanical drawing than a 
 lead pencil, yet no tool is so greatly abused, mainly because it is not 
 very expensive. 
 
 Pencils for drawing are made of various degrees of hardness to suit 
 the purposes for which they are to be used. There are a number of 
 methods of designating the degree of hardness, one of the commonest 
 being to mark them 2H, 4.H, 6H, etc., the harder the pencil, the higher 
 the number preceding the H. 
 
 For drawing on the common Manilla papers, 4!! is a very satis- 
 factory pencil, though 6H wears better and does not require to be 
 sharpened so often. 
 
 To do accurate drawing, it is necessary to keep the pencil well 
 sharpened. The following methods for sharpening are highly desirable. 
 
 ROUND POINT. The first method is known as the "Round 
 Point." This is produced by first cutting away the wood, as shown in 
 the illustration, Fig. i, and then sharpening the lead on a file. 
 
 Round not straight. 
 
 Do this with your knife. 
 
 File the point. 
 
 FIG. 
 
 About one inch from the end of the pencil, beginning on one of the 
 six corners, cut away the wood in a clean manner so as to bare about 
 f " of the lead ; then sharpen it on the file by drawing it towards you. 
 Turn the pencil slowly away from you, taking a fresh hold with each 
 stroke, so as to keep the pencil turning on its axis as it is moved along 
 the file. 
 
 I 
 
 FIG. 2. 
 
 FLAT POINT. The "Flat Point" is very useful when it is 
 desired to draw very fine accurate lines, such as the center lines, con- 
 struction lines, etc. In sharp- 
 ening the flat point, enter the 
 knife about one inch from the 
 end of the pencil on one of the 
 flat sides (not corner), and cut 
 away the wood in the manner 
 shown in the illustration, Fig. 2, 
 baring about one-half inch of 
 the lead. 
 
 To sharpen the lead, slide it 
 back and forth along the file, forming a long chisel-like point. 
 
 The flat side of the lead should parallel the flat side of the pencil 
 when the point is finished. 
 
 PAPER. The drawing paper commonly used in commercial draft- 
 ing rooms is known as Manilla paper. 
 
 There are a great many different grades of this paper manufactured, 
 but the main points necessary to keep in mind when making a selection 
 are: color, erasing qualities, and toughness of fibre. 
 The standard sizes of drawings 
 
 adopted by the Carnegie Technical f i 4 
 
 Schools are: A sheets 22"X3o", B 
 sheets I5"X22", and C sheets n"X 
 
 Drawing paper should be fastened 
 to the board as smoothly as possible; 
 for it is very difficult to make an accu- 
 rate drawing on paper which does not 
 lie flat on the board. 
 
 FIG. 3. 
 
LESSON No. i. Continued. 
 
 The method of mounting paper, shown in the above illustration, 
 Fig. 3, needs very little explanation, and if the student follows the direc- 
 tions with reasonable care, the result will be entirely satisfactory. 
 Place the tacks in the order numbered, stretching the paper in the 
 direction indicated by the arrows. 
 
 Push the tacks well down, so that the heads bind the paper closely; 
 this will also enable the T square to slip over them easily without 
 knocking small chips out of the edge of the blade. 
 
 DRAWING BOARD. T SQUARE. TRIANGLES. The 
 Drawing Board should be made of a soft wood, well-seasoned white 
 
 B 
 
 12. 
 
 FIG. 
 
 pine preferred, so that the thumb tacks may be easily pushed into or 
 drawn from it. 
 
 One end of the board must be perfectly straight, as well as smooth, 
 and free from bumps or high spots. 
 
 A T Square of well-seasoned pear wood is inexpensive and should 
 give satisfactory results. 
 
 The inside edge of the head and the upper edge of the blade should 
 be perfectly straight, and be smoothly and accurately finished. 
 
 The Triangles commonly used by draftsmen are the 45 and the 
 3o-6o angles ; and it is preferable that they should be made of some 
 transparent material. 
 
 The student should realize the necessity of learning to use these 
 tools properly if he desires to do accurate work. The head of the T 
 Square should be kept pressed against the edge of the board when in 
 use; place the hand at A, Fig. 4, rather than at B, and press the blade 
 flat against the board by placing the thumb at C. 
 
 The student should work from the left side of the board at all times, 
 and when drawing -vertical lines, he should use the left side of the 
 triangle as a ruling edge. 
 
 The left side of the triangle is the most natural one to use, as the 
 
 FIG. 5. 
 
 arm is held in an easy position when drawing a line away from the 
 square blade. Besides, when tracing with ink, the student would find 
 it extremely awkward and tiresome to use the right side of the triangle. 
 
LESSON No. i. Continued. 
 
 Hence this general statement: Accurate work is practically impos- 
 sible when both sides of the triangle are used to rule vertical lines on 
 the same drawing. The reason is that triangles are very often inaccu- 
 rate. 
 
 Fig. 4 shows where the trouble lies and gives the student a way of 
 testing the accuracy of his own triangles. 
 
 RULING LINES. A very common cause of inaccurate work is 
 the careless manner in which the lines of a drawing are ruled; if the 
 student will consider the angle formed by the edge of the T Square 
 and the surface of the paper as a groove, and then, leaning the pencil 
 slightly away from the ruling edge, drag the point along this groove, 
 he will have no difficulty in ruling a straight line. 
 
 (a) in the illustration, Fig. 5, shows the correct method, and (b) the 
 incorrect one. 
 
 WEARING THE PENCIL POINT. Draftsmen pick up a 
 good many little tricks or habits that are of advantage in their work. 
 One of them is a method of wearing the pencil point in such a way 
 that it will stay sharp a long time. 
 
 The Flat Point is shown in illustration (a), Fig. 6, and the method 
 is too evident to need further explanation. 
 
 A 
 
 as shown at (b), preserve for a long time the sharp conical point of the 
 pencil. 
 
 SCALE. The draftsman's flat rule (or scale, as it is generally 
 termed), which is graduated in sixteenths on one edge and thirty- 
 seconds on the other, will be found very satisfactory. 
 
 When selecting a scale it is advisable to choose one with the grad- 
 uations cut in a white surface, as the strain on the student's eyes is 
 much less than when using a steel scale or one of plain boxwood. 
 
 ACCURACY. If we stop to analyze the mechanical part of the 
 work of a draftsman, we realize that a great portion of his work con- 
 sists in placing points on the surface of the paper and connecting them 
 with lines, or in drawing lines through them. 
 
 When enough of these points and lines have been placed upon the 
 paper, the drawing of the figure is complete. 
 
 To make a mechanical drawing accurately, it is absolutely essential 
 that the points be placed in their proper positions. 
 
 In connecting them with lines, or in drawing lines through them, 
 the lines should pass through the center of the points. 
 
 If the student is unable to do this properly, it naturally follows that 
 he is unable to make an accurate drawing. 
 
 LINE THROUGH A POINT. ist. With the round-point end 
 of the pencil, make twenty small points upon the paper, one above 
 
 / Point 
 
 FIG. 6. 
 
 When ruling a line with the round point, turn the pencil slowly and 
 deliberately, so that it revolves on its axis as it is dragged along the 
 ruling edge. 
 
 This method will result in lines of an even thickness and color, and, 
 
 FIG. 7. 
 
 another, and about J of an inch apart; then, with the flat -point end of 
 the pencil, rule with the T square a fine, clear, straight, horizontal line 
 through each point, as shown in Fig. 7. 
 
 These lines may be 6 or 8 inches long. Rule ten of them by adjust- 
 ing the blade of the T square up to the point, and ten by placing the 
 
LESSON No. i. Continued. 
 
 
 FIG. 8 
 
THE 
 
 UNIVERSITY 
 
 OF 
 
 LESSON No. i. Continued. 
 
 pencil point in position and bringing the ruling edge gently up to it. 
 These fine lines are called "construction lines," from the fact that 
 when used in practice, the drawing is built upon them. The student 
 should endeavor to "split" the point each time. 
 
 Now, with the round-point end of the pencil, "line in" about 3 
 inches of each line to the right of the point. 
 
 By the term "line in," we mean to make that portion of the line 
 heavier, so that the result will be a strong, clear line, such as should be 
 shown on a finished drawing. When lining in, the student should be 
 very careful to cover the construction line perfectly. 
 
 Lining in a little above or a little below the construction line results 
 in inaccurate work. 
 
 2d. Repeat above, ruling vertical lines and 45 lines, using the T 
 square and the 45 triangle. 
 
 LAYING OFF DIMENSIONS. 3d. Draw fifteen straight lines 
 just 4 inches long; these lines to be horizontal, vertical, and 45. 
 
 In each case use the method described above; first a fine construc- 
 tion line more than 4 inches long, then, using the scale in the manner 
 shown in the illustration, Fig. 8, lay off two points which are exactly 
 4 inches apart, and "line in" that part of the construction line between 
 points. 
 
 THREE-INCH SQUARE. 4th. Using the T square and the 45 
 triangle, construct a 3-inch square. Rule the lines in the order shown 
 by numbers in the illustration, Fig. 9. 
 
 Lines i, 2, and 3 should be construction lines at first. 
 Finish the square by lining in these sides. 
 
 FIG. 9. 
 
 When the square is finished, the length of each side should be 
 exactly 3 inches. 
 
LESSON No. 2. 
 
 ACCURACY. The student should at all times endeavor to make 
 accurate drawings, and he will find that it is only by constant effort on 
 his part that this can be accomplished. 
 
 This lesson is a test in accuracy, and it is necessary that the student 
 should exercise great care in laying out these figures. 
 
 COMPASS POINTS. Get the pencil compasses ready for use. 
 
 In preparing the large compass, remove the pencil leg and, with 
 the file, produce a "flat point" very similar to the "flat point" of the 
 pencil. Trim off the sides so as to get a narrow " flat point " as shown 
 in the illustration, Fig. 10. 
 
 The flat side of the lead should be set at right angles with the 
 needle point. If this requirement is not met with, the compass tends 
 
 Fio. 10. 
 
 The pencil point of the spring-bow compass should be sharpened 
 in the same manner, except that the finished point should be slightly 
 narrower than the one in the large compass. 
 
 SETTING LEAD. When adjusting the legs of the large com- 
 pass, see that the pencil point is slightly shorter than the needle point ; 
 about to the shoulder of the latter. 
 
 Fio. ii. 
 
 to open when it is turned in one direction, and to close when turned in 
 the other. 
 
LESSON No. 2. Continued. 
 
 After the compass legs are properly adjusted for length, test the 
 setting of the lead by drawing a circle clockwise, then, without remov- 
 ing the needle point from the paper, swing one counter-clockwise. 
 The result should be one clear sharp circle; if this is not the case, the 
 lead should be adjusted to correct the error. 
 
 SETTING COMPASS. With the large compass, take a radius 
 of ij inches and describe a 3-inch circle. 
 
 Now, test the circle for a diameter of 3 inches, using the scale. 
 Reset the compass and repeat above test several times, so as to gain 
 confidence in setting the compass. When setting the latter, handle it, 
 and also the scale, as shown in the illustration, Fig. n. 
 
 FIG. is. 
 
 TANGENT CIRCLES. TRIANGLE. Describe three 2-inch 
 circles tangent to one another. 
 
 Surround the circles by a tangent triangle. "Line in" the triangle 
 and test it for accuracy, using the dividers; the sides should be of 
 equal length. 
 
 Repeat this three times. 
 
 Great care should be exercised by the student in laying out this 
 figure, which presents so many chances for error that it is quite diffi- 
 cult to draw correctly. 
 
 SQUARE. Construct a 3-inch square, using the T square and 
 triangle. The square to have rounded corners of -inch radius, made 
 with the bow-pencil compass. 
 
 The finished square should be "lined in" so that there are no 
 visible joints. 
 
 Where rounded corners join straight lines on a mechanical draw- 
 ing, the joint should be so nearly perfect as to be unnoticeable. Care 
 in these little details adds greatly to the attractiveness of a drawing, 
 and they should never be overlooked. 
 
 / 2 3 
 
 FIG. 13. 
 
 The student should observe that in the illustration, Fig. 13, the 
 square is first laid out in faint construction lines, then the corners are 
 rounded, and, finally, the sides are " lined in." 
 
 The rounded corner lines should be made as heavy as it is desired 
 to make the rest of the outline, so that in "lining in" the sides, the 
 lines may be made of the same weight. 
 
LESSON No. 3. 
 
 FLANGED PIN. Make a full-size three-view outline drawing of 
 the flanged pin shown in the illustration, Drawing C-iooo. 
 
 View (a) shows the shank end of the pin as seen from the position 
 of (a). View (A) is a side view of the flanged pin, and (c) is a view 
 of the round end as seen from the position of view (c). The student 
 should study the illustration carefully, and try to understand clearly 
 the meaning of each line. The position of each view is given in rela- 
 tion to the edge of the sheet. 
 
 THE DRAWING. To make the drawing, first lay out the center 
 lines, as they fix the positions of the views. Second, draw view (a), 
 throwing in the circles, then, with the T square and 45 triangle, construct 
 the square representing the shank end. Third, draw view (b), setting 
 the compasses with care each time, so that the circles are drawn exactly 
 
 to scale. Fourth, lay off the lengthwise dimensions of the pin, then 
 draw vertical construction lines through these points (lines of any 
 length) ; now place the T square so as to project the horizontal lines of 
 the pin from the end views. With a J-inch radius, throw in the curved 
 lines representing the chamfer on the shank end. Observe how the 
 radius center line is projected from the end vit-\v. 
 
 FINISHED DRAWING. In finishing the drawing, "line in" 
 the whole outline with care to give it a neat appearance, and to make 
 it clear and distinct, so that all the lines can be easily seen through the 
 tracing cloth. Do not put in any of the dimensions. The finished 
 drawing should show only the outlines of the pin with the vertical and 
 horizontal center lines. 
 
Cenffr Lines 
 
 CLASS Industrial TRADE Machinist 
 NAME John W. Roberts DATE Feb. /6_ 06. 
 
 THE CARNEGIE TECHNICAL SCHOOLS 
 
 PITTSBURGH, PA. 
 
 SCHOOL or APPRENTICES AND JOURNEYMEN 
 
 MECHANICAL DRAWING 
 
 FLANGED PIN 
 
 SCALE full Size 
 
 owa. wo. C./OOO 
 
- OF THE 
 
 UNIVERSITY 
 
 LESSON No. 4. 
 
 MACHINE BOLT. Make a full-size three-view mechanical 
 drawing of the ij-inch machine bolt shown in the illustration, Drawing 
 C-iooi. View (a) represents the end of the bolt head as seen from 
 the position of (a). View (b) is a side view of the bolt and hexagon 
 nut. View (f) is an end view of the threaded end of the bolt and of 
 the hexagon nut as seen from the position of (c). The positions of 
 the views are given in relation to the edges of the paper. 
 
 THE DRAWING. Lay off the center lines first, so that the 
 positions of the views are fixed at the beginning; do not let them 
 "happen" as regards location. 
 
 In drawing view (a), lay out the aj-inch construction circle, and 
 then with the T square and 45 triangle, draw in the outline of the head. 
 
 View (c) is drawn in the same manner, that is, first the zf-inch 
 construction circle, then, using the T square and the 3o-6o triangle 
 draw the outline of the hexagon nut, and finally throw in the ij-inch 
 circle to represent the end of the bolt. 
 
 Having drawn views (a) and (f), now lay off the lengthwise dimen- 
 sions of view (b), and draw vertical construction lines through these 
 points (lines any length). With the T square, project the horizontal lines 
 of the bolt from the end views, these lines to be light construction lines, 
 until their true length is known. Now swing in the various radii, 
 make them as heavy as the final outline is to be, and line in the bolt 
 
 and nut completely, so that the whole outline stands out clearly and 
 distinctly. 
 
 SCREW THREADS. The threaded end of the bolt is indicated 
 by alternate light and heavy lines, the heavy lines being shorter than 
 the light ones. This is a conventional method of indicating screw 
 threads, and it has the merit of being easily understood and is inex- 
 pensive. 
 
 While it is not essential that the space between the light lines should 
 be just the same as the pitch of the thread, or that the lines should be 
 sloped at exactly the correct angle, it is of considerable importance 
 that the threaded surface as a whole should look approximately 
 correct. 
 
 When the slope is correct for a single-thread screw, a line drawn at 
 right angles to the center line of the screw should touch the end of one 
 of the thread lines at one side and pass midway between that line and 
 the next at the opposite side, as indicated by the light dash line d-e. 
 In other words, the slope equals half of the pitch of the thread. 
 
 Place the dimensions just as shown in the illustration, and make 
 the figures carefully, so that there can be no doubt as to their meaning. 
 The dimensions which refer to the position of the different views 
 should be left off, as they were intended to aid the student in locating 
 the views, and have no other value. 
 
CLASS Industrial TRADE Machinist 
 
 N AMI: John W. Roberts DATE Feb. 20. 06. 
 
 THE CARNEGIE TECHNICAL SCHOOLS 
 
 PITTSBURGH, PA. 
 
 SCHOOL or APPRENTICES AND JOURNEYMEN 
 
 MECHANICAL, DRAWING 
 
 MACHINE BOLT 
 
 .SCALE. Full Size 
 
 ona.No.C.IOOl 
 
OF THE 
 
 UNIVERSITY 
 
 OF 
 
 LESSON No. 5. 
 
 LETTERING. The average student does not fully appreciate 
 the value of being able to letter well, and while he is seldom 
 pleased with his lettering, he usually does not like to devote 
 the necessary time to practice. A great many young draftsmen 
 reach the point where they are able to make a neat, workmanlike 
 drawing, the appearance of which they will spoil when they letter. 
 and dimension it. 
 
 In making a study of the types of letters illustrated, take especial 
 notice of the oval, which is the basis of most of the lower-case letters, 
 and observe the proportions of this type; note also the slope of both 
 types. 
 
 The capitals are used mainly for titles and headings, while the 
 lower-case letters are used for all notes shown on drawings and for all 
 other purposes, except for titles and headings. 
 
 As an aid in learning to letter, it is well to use guide lines as shown 
 
 in the illustration. The student will find the slope guide lines a great 
 help also in making letters of uniform appearance. 
 
 FIGURES. What has been written in regard to lettering applies 
 equally well to figures. 
 
 It is of great importance that the student should learn to make his 
 figures so well that no one should have any trouble in reading them 
 easily and quickly. Mistakes in the shops are very frequently caused 
 by poorly written figures on drawings, and these mistakes are often 
 very costly. The value of using great care at all times in placing the 
 dimensions on drawings is thus clearly shown. 
 
 THE LESSON. Make a neat pencil copy of the illustration, 
 using care with both letters and figures; note carefully the proportions 
 of both. Leave off figures showing spacing of guide lines, as these 
 were intended merely as an aid to the student in laying out his lesson 
 sheet. 
 
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 J IT I 
 
 CLASS Industrial TRADE Machinist 
 NAME John W. Roberts ct.rz Nov. 12, 06 
 
 THE CARNEGIE TECHNICAL SCHOOLS 
 
 PITTSBURGH, PA. 
 SCHOOL OF APPRZNTICCS AND JOURNEYMEN 
 
 MECHANICAL DP AWING 
 
 LETTERING - F/GURES 
 
 SCALE Full Size owa.No. C-/002 
 
Of THE 
 
 UNIVERSITY 
 
 OF 
 
 LESSON No. 6. 
 
 SKETCHING. Whatever course in mechanical drawing the stu- 
 dent may pursue, he will sooner or later desire to know something about 
 sketching, or, at least, he will feel the need of it. 
 
 A knowledge of sketching is exceedingly useful to men of most of 
 the trades, and the lessons on this subject have been planned with the 
 belief that they may assist the students to use their pencils more freely 
 and easily in making simple mechanical drawings free-hand. 
 
 METHOD. The method that we shall follow, we shall call the 
 "Short -stroke Method," from the fact that as we draw a line in any 
 direction, it is not made by a single stroke of the pencil, but by a series 
 of short strokes. There should be the smallest possible opening be- 
 tween the ends of these short lines, and it would be better still if the 
 ends were to just touch without overlapping. 
 
 The object of using these short strokes is to enable the student to 
 correct an error in direction at any point along the line. The result is 
 that the general direction of the line is straight, and though there may 
 be slight errors along the line, they in nowise cause any doubt as to 
 its meaning. 
 
 PENCILS. For sketching, a pencil equalling an H or HB in hard- 
 ness will give very satisfactory results, though a zH Koh-i-noor will 
 last much better. The latter, however, is just a little too hard except 
 when used on Manilla paper. 
 
 Learn to hold the pencil easily and naturally between the first and 
 second fingers and the thumb, in a manner very similar to that used in 
 writing. 
 
 Do not turn the paper to suit the direction in which a line is to be 
 drawn, but fasten it down to the drawing board and try to develop that 
 freedom of movement of fingers, wrist, and arm which will enable one 
 to draw a line in any direction with equal ease. 
 
 In drawing straight lines as indicated on the illustration, the student 
 will soon discover that they are made in certain directions by a move- 
 ment of the wrist mainly. In other directions it is mostly a movement 
 of the fingers which gives the best results. 
 
 It is quite difficult to make neat circles free-hand, but by putting 
 into practice the following suggestions, the student should obtain satis- 
 factory results. 
 
 The student should sit upright while drawing, so that he may the 
 better get a clear view of his work as a whole. By having the head 
 well up over the work, the eyes can direct the movements of the pencil 
 better, and they are in a better position to see if the desired shape is 
 growing under the pencil, than if held close to the work. Start at a 
 point on the left side, as indicated by the arrows, and with short strokes 
 form the upper half of the circle. Then, starting at the same point, 
 form the lower half in the same manner. 
 
 THE LESSON. Fasten the drawing paper smoothly to the 
 board and divide it into sections, as shown in the illustration. 
 
 The straight lines should be drawn about J inch apart and in the 
 directions indicated by the arrows. 
 
 Draw the circles to the sizes shown, without using a rule; try to 
 see how nearly correct you can make them by the eye. 
 
CLASS Industrial TRADE Machinist 
 
 HAME John W. Roberts DATC Mar. PO- Of. 
 
 THE: CARNEGIE TECHNICAL 
 
 PITTSBURGH, PA. 
 
 SCHOOL or APPRENTICES AND JOUR 
 
 MECHANICAL CrffAWtHG 
 
 SCHOOLS 
 
 SKETCHING 
 
 SCALE Full Size owe. NO. C. IO03 
 
OF THE 
 
 UNIVERSITY 
 
 OF 
 
 LESSON No. 7. 
 
 PROPORTIONS. It is a very valuable acquirement, when 
 sketching, to be able to make the details of a drawing of the proper 
 proportions in relation to each other. 
 
 The scale of a sketch is of little importance, provided it is large 
 enough to show clearly the piece or pieces we desire to illustrate. But 
 that which is of importance is that each piece, or detail of the piece, 
 should be drawn to the same scale. 
 
 To obtain this result it is quite necessary that the student should 
 train his faculty of observation so as to have a sense of measurement, 
 
 and so that, without the aid of a rule, he may be able to draw a sketch 
 approximately to a given size. 
 
 The student will be helped to develop this faculty if, in sketching, 
 he practises drawing to a certain scale or to given dimensions. 
 
 LESSON. Make a neat free-hand full-size drawing of the figures 
 shown in the illustration. Draw each figure to the dimensions given, 
 as nearly as possible, without using a rule. 
 
 Observe that two views are shown of each piece, and try to see 
 the relation between the views. 
 
i r 
 
 <\j 
 
 4 
 
 THE CARNEGIE TECHNICAL SCHOOLS 
 
 Ci/iss Industrial T/?ADE Machinist 
 
 John W.Roberts DATE Mar. PO.O6. 
 
 PITTSBURGH, PA. 
 SCHOOL Of APPREMTICZS AND Jo 
 
 MECHANICAL DRAWING 
 
 SKETCHING 
 
 Size Dw6.no. CLIO04 
 
LESSON No. 8. 
 
 METHOD OF HOLDING PEN. In learning to trace, one of 
 the first problems which confronts the student is how to hold the 
 instruments. 
 
 In general, the ruling pen and the pen point of the compass should 
 be held in such a manner as to bring the points of both jaws on the 
 paper at the same time, as shown at (b) of the illustration, Fig. 14. 
 
 tt 
 
 
 a 
 
 Fir.. 14. 
 
 Do not lean the jien either toward the ruling edge or away from it, but 
 hold it in a vertical plane, thus obtaining clean even lines free from a 
 ragged edge. 
 
 While the pen should not be leaned toward or away from the ruling 
 edge, it will be found that the ink will flow more freely if the pen is 
 leaned slightly in the direction in which the line is being ruled, as shown 
 at (a). 
 
 When using the pen compass for large circles, the legs may be bent 
 at the joints, so as to meet these conditions. 
 
 TRACING CLOTH. The student will find one side of the trac- 
 ing cloth with a glazed or calendered surface, while the other side has 
 a dull finish. If the glossy side is used, it will be necessary to dust the 
 surface with powdered chalk or talcum powder, as the ink will not flow 
 freely otherwise. In a great many drafting rooms the dull side of the 
 cloth is used from preference, as it takes ink very well without powder 
 of any kind, though the powder makes the ink flow more freely. 
 
 I 
 
 1st. Circles and Radii 
 
 3rd. Vertical lines 
 
 2nd Horizontal lines 
 
 4th. Angular lines 
 
 Fin. 15. 
 
 CARE OF PENS. A common mistake of most beginners is to 
 fill the pen with too much ink, with the result that, before they realize 
 it, there is a big blot on their work. This is not necessarily caused by 
 the pen being filled too full, but it is frequently the cause. It is better 
 to fill the pen oftener and to use less ink at one time. 
 
 Another very good habit to acquire is to wipe out the pen each 
 
 Of THE 
 
 UNIVERSITY 
 
LESSON No. 8. Continued. 
 
 time fresh ink is to be put in, as the ink flows more freely from a clean 
 pen than from a dirty one. 
 
 TRACING FLANGED PIN. Make a tracing of the pencil 
 drawing of the flanged pin. 
 
 When beginning a tracing, tack the cloth down carefully over the 
 pencil drawing, then set the compass pen to the desired width of line 
 bv testing on the edge of the sheet, and, after it is properly adjusted, 
 
 throw in all the circles and radii. Then, beginning at the top, rule in 
 the horizontal outlines; next, beginning at the left side, rule in the 
 vertical outlines and finally the angular lines. 
 
 In ruling horizontal lines, use the T square as a ruling edge. For 
 vertical lines, use the left side of the triangle, which should be held 
 against the T-square blade. 
 
 Do not use the scale as a ruling edge. 
 
OF THE 
 
 UNIVERSITY 
 
 OF 
 
LESSON No. 9. 
 
 TRACING MACHINE BOLT. As mentioned in Lesson No. 8, 
 begin by adjusting the compass pen to the width of line desired for an 
 outline.' In deciding on the width of line, the student should bear in 
 
 01: 
 
 1st. Circles and Radii 
 
 3rd. Vertical lines 
 
 o 
 
 2nd Horizontal lines 
 
 Dimension lines 
 
 . Angular lines 
 
 Projection lines 
 
 Sfh. Projection and Dimension lines 
 
 Dimensions- Notes 
 FIG. 1 6. 
 
 mind that to get blue-prints with clear white lines, it is necessary that 
 the lines of the tracing be fairly heavy; not the fine, "pretty" lines 
 that beginners are so prone to use. 
 
 The illustration shows the various steps in making a tracing: First, 
 throw in all the circles and radii ; then, beginning at the top, rule in all 
 the horizontal outlines; next, starting at the left side, rule in all the 
 vertical outlines; and, finally, rule in the angular outlines. 
 
 Now, adjusting the pen to a much finer line, rule in the projection 
 lines; these lines for drawings of small figures should be composed of 
 dashes i to f inch long, and for large figures J to f inch long. Do not 
 let the projection lines touch the figure, but leave a slight opening 
 between the end of the line and the figure. 
 
 Next, rule in the dimension lines ; these lines for drawings of small 
 figures should be solid except for the opening left for the dimension, 
 but on drawings of large figures they may be broken lines of long 
 dashes, the length to suit the size of the drawing. 
 
 Now, place the arrow heads on the dimension lines and put in the 
 dimensions, using care to make the figures clearly. 
 
 FINISHED DRAWING. In the finished drawing there should 
 be a marked contrast between the weight of the outlines of the figure, 
 and of the center, projection, and dimension lines; the latter should be 
 decidedly lighter than the outlines. When these various lines are 
 drawn to the proper proportions and are well arranged, the figure 
 seems to stand out by itself and is much more easily under- 
 stood. 
 
 When the drawing is completed, print the title on neatly and care- 
 fully, as the looks of a good drawing will be spoiled if the printing is 
 done in a careless, slipshod manner. 
 
 Use a Gillott's No. 303 pen point for lettering and dimensioning 
 
 the drawing. 
 
LESSON No. 10. 
 
 HIDDEN SURFACES. Until the present time we have been 
 using lines which could be seen on the surface, or which represented 
 the surface of the figures that we have used as subjects for our draw- 
 ing lessons. 
 
 In mechanical drawing it is constantly necessary to show by some 
 means, surfaces or details of parts that are hidden from view behind 
 the surface shown by solid lines. 
 
 Unless these surfaces could be indicated by some simple method, 
 it would often be necessary to make additional drawings or, at least, 
 additional views to show clearly the shape of the figure illustrated. 
 
 The method commonly used to indicate these hidden surfaces is to 
 draw them in, in the proper position, but to use dotted lines for this 
 purpose. These dotted lines, or "hidden lines," as they are generally 
 called, have a distinctly different appearance from the solid outlines of 
 
 the rest of the drawing, and their meaning should be readily under- 
 stood. 
 
 THE LESSON. These hidden lines are the essential feature in 
 the present lesson. As they are constantly used in mechanical draw- 
 ing, we wish to call the student's attention to them. 
 
 Make a neat free-hand sketch of the clamp shown on Drawing 
 -1005. 
 
 Finish your sketch neatly; copy carefully all dimensions, and be 
 sure to place your name, the drawing number, and the title of the 
 piece upon it. 
 
 From your sketch make a full-size pencil drawing of the clamp; 
 finish it completely with all dimensions, the title, etc. 
 
 Use the " Short -stroke Method" in making your sketch. 
 
f 
 
 TT 
 
 $ 
 
 THE CARNEGIE TECHNICAL SCHOOLS 
 
 ctxss Industrial TRAOC Machinist 
 
 John W. Roberts DATE Oct. 6-O6. 
 
 PITTSBURGH, PA. 
 
 SCHOOL or APPRENTICES AND JOUR 
 MECHANICAL DRAWING 
 
 CLAMP 
 
 SCALE Full Size DWG.NO. C.IOO5 
 
LESSON No. ii. 
 
 SECTIONING. \Vhen making drawings it is often necessary to 
 show at least one view of the piece or pieces illustrated, with part cut 
 away, or "in section," as it is generally termed. 
 
 The advantage of this method is that it helps to show the shape of 
 the piece more clearly, and often the dimensions can be placed to bet- 
 ter advantage on a sectional view. 
 
 As an aid in indicating that a piece is in section, the surface is cov- 
 ered with lines called "section lines." These lines are drawn with the 
 aid of a 45 triangle as a ruling edge, the triangle being held against 
 the T-square blade and moved for each line. 
 
 In this course of lessons we will use the section lines shown on 
 Drawing C-ioo6 for all metals, the only variation being that the lines 
 
 should be spaced close together for small pieces and farther apart for 
 large ones. 
 
 Where two or more pieces assembled together are shown in section, 
 the different parts are shown more clearly by sloping the section lines 
 in opposite directions where the parts join. 
 
 THE LESSON. The important point in this lesson is the method 
 of showing a piece in section. 
 
 Make a neat free-hand sketch of the sleeve shown on Drawing 
 C-ioo6; copy carefully all dimensions, and all necessary data. 
 
 From your sketch make a full-size pencil drawing of the sleeve. 
 Try hard for accuracy. 
 
-C\| 
 
 
 ,1- 
 
 f 
 
 CLASS Industrial TBADC Machinist 
 NAME John W.Roberts DATE Oct. 24- O6. 
 
 THE CARNEGIE TECHNICAL SCHOOLS 
 
 PITTSBURGH, PA. 
 
 SCHOOL OF APPPENrtCES AND iJo 
 MECHANJCAL DRAWING 
 
 SCALE Full Size 
 
 OWO.NO. C.I006 
 
LESSON No. 12. 
 
 PROJECTION. Mechanical drawings to be clearly understood 
 and easily read should be made after certain fixed rules as to the 
 arrangement of views in relation to each other. 
 
 There are usually several correct arrangements for the different 
 views of a body, but in each of them the same relationship between the 
 
 Projection lines 
 
 Plane 
 
 FIG. 17. 
 
 views is maintained. To fully grasp the meaning of this, a knowledge 
 of projection is necessary. 
 
 Even- student of Mechanical Drawing should make a study of the 
 subject of projection, as a thorough knowledge of this subject is neces- 
 sary in order to read drawings intelligently, and it is absolutely essen- 
 tial for one who wishes to become a good draftsman. 
 
 The definition of the word projection (as applied to Mechanical 
 Drawing), given in the Universal Dictionary of Mechanical Drawing 
 
 by Prof. Geo. H. Follows, is: "To throw forward in parallel rays or 
 straight lines." "Projection means either the act or the result of pro- 
 jecting parallel rays from the surface of a body, and of cutting these 
 rays with a plane, so as to obtain on the plane a shape, corresponding 
 
 Plane A 
 
 Plane B 
 
 'Projection lines 
 
 FIG. i 8. 
 
 point for point with that of the body. In Mechanical Drawing these 
 rays are called projection lines." 
 
 Fig. 17 is an illustration of a V block shown in perspective, the 
 end view of the block being projected upon the plane. Projection 
 lines are thrown out from the points or corners of the body, and the 
 
 OF THE 
 
 UNIVERSITY 
 
LESSON No. 12. Continued. 
 
 main points where the plane intersects these lines are those which are 
 used in developing the outline of this body. 
 
 This perspective is used simply to illustrate the principle of pro- 
 jection, while the illustration shown in Fig. 18 is an example of a 
 mechanical projection of the same block, showing the three views in 
 the same plane. 
 
 Theoretically, we start with the assumption that the body is located 
 directly under the top plane, and that the top view is projected up to 
 this plane. The end view is projected upon plane A, and this plane is 
 then swung up parallel with the plane of the top view. The same 
 process follows for the side view; it is projected upon plane B, which 
 is swung up parallel with the other two views, all of the views now 
 being in the same plane. In actual practice, the draftsman would lay 
 out the different views in the same relation to each other, but he would 
 simply construct the views by means of his T square, triangles, and 
 scale. 
 
 As an aid to remember true projection, and in order to enable the 
 student to ascertain the correctness of his projection drawings regard- 
 less of the manner in which the views may be arranged, the following 
 method is recommended. 
 
 Observe if the different views bear the same relation to each other 
 as those shown in Fig. 18; that is, that, from the position of the end 
 
 view, looking toward the top view, one will see what has been drawn 
 for the end view, and from the position of the side view, looking 
 toward the top view, one will see what has been drawn for the side 
 view. Furthermore, from the position of the top view, looking toward 
 the end view and side view, one can see what has been drawn for the 
 top view. 
 
 THE LESSON. A number of pieces of various shapes are shown 
 on Drawing C-ioc>7, some of the views of each piece being incomplete. 
 The student is expected to lay out a full-size pencil copy of this draw- 
 ing, with all of the views properly completed. 
 
 To finish these correctly it will be necessary for the student to keep 
 in mind what has been written above in regard to proving that the 
 views are properly projected. 
 
 Do this work neatly, showing all necessary hidden lines, but remem- 
 ber that the important point is to show a clear understanding of simple 
 projection. 
 
 Place all dimensions as shown, and print the title on neatly. Qual- 
 ity, not speed, counts at present in all this work. 
 
 In Fig. i, view C is complete; finish A and B. 
 
 In Fig. 2, view B is complete; finish A and C. 
 
 In Fig. 3, view C is complete; finish A and B. 
 
 In Fig. 4, view C is complete; finish A and B. 
 

 - 
 
 
 , 
 
 /'Tv (v~ 
 
 \ (8 
 
 t 
 
 ><* 
 
 1 
 
 ^ 
 
 4 
 
 Planes 
 
 4 
 
 M /" . 
 
 /I 
 
 
 
 c 
 
 
 
 1 
 
 
 -* 
 
 t 
 
 t 
 
 1 v i* 
 
 r 
 
 '*t 
 
 ^ c 
 
 CLASS Industrial TRADE Machinist 
 
 John W.Roberts DATE Sepf. ^2.O7 
 
 THE CARNEGIE TECHNICAL SCHOOLS 
 
 PITTSBURGH, PA. 
 
 SCHOOL or APPRENTICES AND JOURNEYMEN 
 
 MECHANICAL DRAWING 
 
 PROBLEMS IN PROJECTION 
 
 SCALE Full Size owa. NO. C.I 007 
 
OF THE 
 
 UNIVERSITY 
 
 OF 
 
 LESSON No, 13. 
 
 FLANGED PULLEY. The figures on Drawing C-ioo8 repre- 
 ent a side view and a true sectional view of a Flanged Pulley. 
 
 The conventional method of indicating screw threads is used in the 
 holes for the set screws; note that the threads appear to be left hand. 
 These threads are in reality right hand, and it is desired that the stu- 
 dent shall reason out for himself just why it is correct to show the 
 threads in this manner. 
 
 This lesson is intended to give the student a clearer conception of 
 the subject of sectioning; to help him to make a mental picture of 
 
 what the pulley looks like when cut in half along the vertical center 
 line. Make a free-hand sketch of the pulley, copying carefully all 
 dimensions and necessary information. From this sketch make a 
 full-size pencil drawing of the pulley, placing all dimensions just as 
 shown on the illustration. 
 
 When dimensioning a drawing, bear in mind that your drawing is 
 to be used as an instrument to furnish exact information to some one 
 in the shop, and unless you do your work carefully and accurately, 
 costly mistakes may be the result. 
 
Drill -Tapj -2O Thd. 
 :. Sef Sc. 
 
 
 ct/ss Industrial T/IOF Machinist 
 NAME John IV Roberts DATE: Oct. 16- O6. 
 
 THE CARNEGIE. TECHNICAL SCHOOLS 
 
 PITTSBURGH, PA. 
 SCHOOL OF APPRENTICES Atvo JOURNEYMEN 
 
 MECHANICAL DRAWING 
 
 FLANGED PULLEY 
 
 SCALE Full Size DWG.Ne.C-/OO8 
 
LESSON No. 14. 
 
 HAND WHEEL. In our previous lessons on sectioning we have 
 dealt with true sections, while, in the present lesson, the sectional view 
 shown of the Hand Wheel is what is called a "conventional section." 
 In other words, it is not a true section, but a special one which is 
 used because it illustrates the shape of the piece more clearly for 
 the pattern maker and machinist. The draftsman can lay it out 
 more easily and quickly as well an economy that should be con- 
 sidered. 
 
 As an illustration of the convenience of special sections, note the 
 conventional section of the arm of the hand wheel; without this section 
 it would be pretty hard to give the pattern maker a clear idea as to the 
 shape of the arm. 
 
 This conventional method of sectioning is used constantly on draw- 
 ings of such pieces as wheels, pulleys, and gears with arms. 
 
 LESSON. Make a full-size pencil drawing of the Hand Wheel. 
 
 Place all dimensions just as shown, with the exception of those that 
 refer to the handle; these dimensions should be left off, as they were 
 intended merely as an aid to the student. Mark this part "No. 2 
 Handle." When the pencil drawing is complete, make a tracing of it. 
 Try to do this work neatly; make the lines of the tracing clear and dis- 
 tinct, keeping in mind the instructions given in Lesson No. 9. 
 
 When drawing the ball of the handle, -do not try to make the two 
 radii (ij and i inch) touch, as they should be joined with a straight 
 line. The student should bear in mind that where radii swinging in 
 opposite directions are to be joined, that a straight line should be used 
 for this purpose, otherwise the line appears to have a corner or uneven 
 place. Where the radii are small, as at the stem of the handle, the 
 rule may be overlooked. 
 
CLASS Indus fr/af .TRADE Machinist 
 HAMC <John W. Roberts. DATE 
 
 THE. CARNEGIE TECHNICAL SCHOOLS 
 
 PITTSBURGH, PA. 
 
 SCHOOL or APPRENTICES AND JOURNEYMEN 
 
 MECHANICAL DRAWING 
 
 8 HAND WHEEL 
 
 SCALE full Size oiva. NO. C-IOO9 
 
LESSON 
 
 DRAWING TO SCALE. In all of our previous lessons, the 
 pieces illustrated have been drawn full size; in our present lesson we 
 shall take up the subject of drawing objects smaller than full size, or 
 "drawing to scale," as it is generally termed. 
 
 In most modern commercial drafting rooms, the drawings are made 
 on paper of certain sizes. These standard sizes (usually three or four) 
 are adopted to suit the needs of the manufacturer, and each of the 
 machine parts built is shown on one of these standard -size -sheets. 
 
 Small parts may be drawn full size, but large ones must, of necessity, 
 be drawn to a smaller scale, as J size, J size, and J size. 
 
 These are the scales usually adopted by manufacturers of machinery. 
 The piece is drawn to the scale necessary for clearness and best suited 
 to one of the standard-size sheets, while the dimensions are placed in 
 the same manner as if the piece were drawn full size. In other words, 
 the dimensions must show the sizes to which the piece is to be finished 
 in the shop. 
 
 In drawing to a given scale, that scale becomes our unit of measure- 
 ment. As an illustration, take our present lesson, in which the student 
 is expected to make a half-size drawing of the Lathe Face Plate. 
 
 As J inch is our unit of measurement, J inch equals i inch, but 
 instead of dividing each dimension by two, read it thus: "if halves 
 for if inches, 5 halves for 5 inches, f halves for f inch, etc." 
 
 If the student will carefully study the illustration in Fig. 19, he 
 will observe that the divisions can be made on the scale by simply 
 training the eye to perform this operation. 
 
 As an aid in readily locating a dimension on the scale, look for the 
 nearest large graduation ; the full-size dimension on Fig. 19 is sjf inches, 
 a thirty-second less than sf inches, which figure can be found at once. 
 To find s|| inches half size, look for sf inches half size and point back 
 toward zero one-half of the space between graduations. To locate 
 SJ| inches quarter size, look for sf inches quarter size and point back 
 toward zero one-fourth of the space between graduations, sff inches 
 one-eighth size is located in the same manner. 
 
 THE 
 UNIVERSITY 
 
 By this method it is necessary for the student to keep but one 
 dimension in mind when making a division, and when he learns to 
 read his scale properly, he is much less liable to make mistakes than if 
 he were to make his divisions in the usual way. 
 
 Full Size 
 
 ones 
 
 5& halves 
 
 " j* SH quarters-^ 
 \5geiffMhs 
 
 |'i'|T|'iTi'|'iTr|'i'n'|'i'|'i'rn' '[iTifi'pi 1 Tri!r|T|'i'|T|'i T'l'i'iTiTi 'I 
 
 I I 
 
 FIG. 19. 
 
 To get a radius for half-size circles, set the compasses to the dimen- 
 sion quarter size. For example, to draw the end view of the hub 4-inch 
 diameter half size, take a radius of 4 quarters. 
 
 LESSON. From the illustration, make a half-size pencil drawing 
 of the Lathe Face Plate. 
 
 Section AB is cut along the line AB, and is a conventional method 
 of showing a true section along this line. 
 
 Section CD is necessary to give the pattern maker a clear idea of 
 the shape of-the metal back of the T slot. 
 
 Where dimensions are given in decimals, draw that part to the near- 
 est sixty-fourth. 
 
 Study the illustration carefully, so as to get a clear idea of the mean- 
 ing of each line. Do not simply copy; try to make a mental picture of 
 the shape of the piece. 
 
 Use the edge of your scale, which is graduated in sixteenths, and 
 work from dimensions given. 
 
Section C~D 
 
 Bore 2^034 
 Tap 2/~ 6 Thd. 
 
 a s. stct. 
 
 Section A-B 
 
 THE CARNEGIE TECHNICAL SCHOOLS 
 
 CLASS Industrial TRADE Machinist 
 
 HAHC John W, Roberts DATE Oct. 2 O- 06. 
 
 PITTSBURGH, PA. 
 
 SCHOOL OF APPRENTICES ANO J 
 
 MECHANICAL DRAWING 
 
 LATHE FACE: PLATE: 
 
 SCALE j Size 
 
 owe. NO. C.IOIO 
 
LESSON No. 16. 
 
 ASSEMBLY DRAWINGS. It is common practice in most 
 drafting rooms to make drawings which show several details of a 
 machine fastened together. These drawings are called "assembly 
 drawings," and they are of great value to the men in the shop who 
 erect or assemble the machines. They are very necessary also when 
 ordering the "stock" or materials from which to build the machines, as 
 the "Bill of Material" contains all the necessary information for this 
 purpose. 
 
 The illustration is of a "Positive Clutch Coupling," so called from 
 the fact that the motion transmitted by this coupling is positive, there 
 being no chance for one-half to slip or slide over the other, as in a 
 coupling where one-half turns the other by means of friction. 
 
 The stationary half is keyed tight to the shaft on which it is mounted. 
 The sliding half, which is on a separate shaft, is fitted in such a manner 
 as to slide freely lengthwise on the shaft, while revolving with it. 
 
 These shafts are held in line by bearings, one shaft being tie 
 
 "driver," the other the "driven." When the sliding half of the coup- 
 ling is moved over until the ends of the halves lock together, the two 
 shafts revolve as one. 
 
 The end view of the stationary half shows clearly the shape of the 
 lugs for interlocking. 
 
 Note the method of indicating a break in the shaft; this method is 
 always employed to indicate a break in a round piece of metal. 
 
 LESSON. Make a half-size drawing of the coupling. 
 
 The sizes of keys may be obtained from the "Bill of Material." 
 
 When laying out the "Bill of Material," use great care with letters 
 and figures, as this information must be accurate and should be clearly 
 shown. 
 
 When the pencil drawing is finished, make a tracing of it; the lines 
 of the tracing should be fairly heavy, so that blue-prints made from it 
 will show the figure with perfect clearness. 
 
 or THE Q 
 
 UNIVERSITY 
 
 OF 
 
Sliding fit' 
 
 *' 
 
 1 r/~ 
 
 Press //'/ 
 
 BILL or MATERIAL 
 
 Item 
 NO. 
 
 Description and Material 
 
 Pat. No. 
 
 Req. 
 
 f * 
 
 
 
 Stationary Clutch C.I. 
 
 A 2O1 
 
 I 
 
 T* 
 
 i 
 
 Sliding Clutch C.I. 
 
 ft 
 
 1 
 
 - 
 
 
 $xje x-SJ Feather Key C.R. 
 
 
 1 
 
 1 
 
 f"xjT*34" Key C.R. 
 
 
 1 
 
 r 
 
 oj . 
 
 7' 
 
 -1" 
 
 " IS ' 
 
 *" '4- 3 
 
 Industrial TRAOC Machinist 
 
 John W. Roberts OATC Oct. Pfi- 06. 
 
 THE CARNEGIE TECHNICAL SCHOOLS 
 
 PITTSBURGH t 'PA. 
 
 SCHOOL OF APPRENTICES AND JOURNEYMEN 
 MECHANICAL DRAMMQ 
 
 POSITIVE CLUTCH COUPLING 
 
 SCALE Size 
 
 DWQ. NO. C-IQII 
 
OF THE 
 
 UNIVERSITY 
 
 LESSON No. 17. 
 
 COUPLING. The assembly drawing used for the present lesson 
 is of a " Compression Shaft Coupling." 
 
 This coupling can be clamped around the ends of two shafts, the 
 
 . ^ Across 
 
 Across 
 
 Corners 
 
 Height or 
 Thickness 
 
 Bolt dia. 
 
 X Bolt dia. 
 
 FIG. 20. 
 
 two halves of the coupling being held together by means of the bolts 
 shown. The upper half of the coupling is fitted with a key which 
 keeps the shafts in line. 
 
 On assembly drawings it is not customary to give the dimensions of 
 
 pins, screws, bolts, and similar details. The sizes only of these small 
 parts are given, so that they can be ordered from the storeroom, where 
 they are kept in stock. 
 
 Most modern drafting rooms are supplied with "Data Books" or 
 sheets of stock sizes, from which the draftsmen obtain all necessary 
 dimensions of these small details. 
 
 No dimensions are given for the bolts shown in the present lesson, 
 but the student may obtain the size of bolt and nut from the "Bill of 
 Material." 
 
 From the following data the student is expected to calculate for 
 himself all dimensions necessary to draw bolts and nuts to the correct 
 size. 
 
 If in doubt as to meaning of terms given below, refer to illustration, 
 Fig. 20. 
 
 SIZES OF NUTS AND BOLT HEADS. 
 
 Sq. nuts or bolt heads across flats = ijxbolt dia. + J inch. 
 
 " " " " " corners= dia. across flats x" 1.414. 
 Hex. " " " " " flats = i*X bolt dia. + i inch. 
 
 " " " " " corners = dia. across flats X 1. 1 56. 
 Height or thickness of nuts=bolt diameter. 
 
 " " " " bolt heads=bolt diameterX.So. 
 "Length of Bolt" always refers to length under the head. Notice 
 Drawing C-iooi, Lesson No. 4. 
 
 Make a half-size pencil drawing of the coupling, Drawing C-ioi2. 
 Remember that accuracy and neatness are points of great import- 
 ance. 
 
 Make a tracing of the finished pencil drawing. 
 
Ream fit 
 
 Section A-B 
 
 B/LL or MATERIAL 
 
 Item 
 No. 
 
 Description and Ma ferial 
 
 Pat No. 
 
 ^9: 
 
 (!) 
 
 Half Coup/ing C. 1. 
 
 A. 200 
 
 / 
 
 1 
 
 ff> 
 
 .. 
 
 / 
 
 
 
 i*2 M.B.Tap Bo/f nith Nut 
 
 
 6 
 
 i 
 
 f*i,'*/o'rer 
 
 
 / 
 
 CLASS Industrial THADC Machinist 
 
 HAMC John W.Roberts DAT,: Oct. 20-O6. 
 
 THE CARNEGIE TECHNICAL SCHOOLS 
 
 PITTSBURGH, PA. 
 
 SCHOOL Of APPRENTICES AND JOURNEYMEN 
 
 MECHA NtCAL DP-* WlfijQ 
 
 COMPRESSION SHAFT COUPLING 
 
 SCALE Size 
 
 Diva NO. C-IOI2 
 
LESSON No. 18. 
 
 PROJECTION. Two problems in projection are shown on Draw- 
 ing C-IOI3- 
 
 (a), Fig. i, is an end view of a block with all dimensions shown. 
 (6) is a partly finished front view, showing the length of the block. 
 
 View (a) is projected upon a plane which is set at an angle of 45; 
 this plane is then raised to a vertical position and swung around one- 
 fourth turn or 90, so as to show the front view (6). 
 
 View (r) should be an end view of the block tilted at an angle of 45. 
 
 Lay out the three views full size, finishing them completely and 
 placing them in the positions indicated on the drawing. 
 
 Fig. 2 is a side view of a frustum of a hexagonal pyramid with the 
 base cut away at an angle of 30. 
 
 The small end or top of frustum is ij inches across flats, and the 
 large end 2 inches across flats before cutting off a portion of the base, 
 as shown by the dotted line. 
 
 The student is expected to lay out the three views of this piece, the 
 top and end views to be placed in the positions indicated on the draw- 
 ing. 
 
 Remember that this lesson is intended purely as a study in pro- 
 jection, and do this work very carefully. 
 
 If the student fully grasps the principles of projection, he will have 
 mastered one of the most difficult and most important portions of the 
 subject of mechanical drawing. 
 
 It is not necessary to dimension the pencil drawing. 
 
 OF THE 
 
 UNIVERSITY 
 
 OF 
 
P/ang 
 
 Project end vien here 
 c 
 
 F/g.2 
 
 End vieiv here 
 
 THE CARNEGIE TECHNICAL SCHOOLS PPOBLEMS ,N PROJECT/ON 
 
 CLASS Industrial TRADE Machinist 
 
 HAME John W Roberts DATE Oct. 10- O7 
 
 PITTSBURGH, PA. 
 
 SCHOOL or APPRENTICES AND J 
 
 MECHANICAL DRAWING 
 
 SCALE Full Size DWG NO.C-IQ/3 
 
LESSON No. 19. 
 
 THE ELLIPSE. Make a neat pencil drawing of an ellipse by 
 the three methods indicated, and of the elliptical curve shown on 
 Drawing 0-1014. 
 
 When drawing the ellipse, make the major or long axis 3$ inches, 
 and the minor or short axis 2 inches in each case. 
 
 For Fig. i, lay off the major and minor axes to the lengths given 
 above; take a straight edge made of any suitable material, as card- 
 board or wood, and, on one edge, mark off the points AB equal to 
 half the minor axis; from A, mark off point C equal to half the major 
 axis. Place the straight edge so that the point B comes on the major axis 
 and point C on the minor axis; now, with the pencil, mark a point on 
 the drawing paper at A. Shift the straight edge and repeat (keeping 
 B and C on the major and minor axes respectively), placing a sufficient 
 number of points on the paper to enable you to trace a curve through 
 them easily. 
 
 The method illustrated in Fig. 2 is of such a nature that the student 
 should be able to solve the problem without assistance. 
 
 Fig. 3 is known as the "Three-radii Method." 
 
 Construct the rectangle ADCEB. Draw the diagonal AC. Through 
 D, draw DF at right angles to AC. Then, F is the center for arc 
 GCH, and J is the center for arc KAL. 
 
 Make OM=OC. Describe the semicircle AM. 
 
 Make OP=CN. With center F, describe arc RPS. Make AQ= 
 ON. Then, with J as center and radius JQ, describe arc intersecting 
 arc RPS at T. T is the center for the tangent arc LG. 
 
 To construct the curve shown at Fig. 4, divide the base lines of 
 the curve into the same number of equal parts (any number) and con- 
 nect these division points by straight lines. The combined outer sur- 
 faces of these lines form the desired curve. 
 
Fig. I 
 
 N 
 
 Fig. 3 
 
 CLASS. Industrial TKAOC Machinist 
 
 W. Rober+a DXT c Dec. AS- 06 
 
 THE CARNEGIE TECHNICAL SCHOOLS 
 
 H, PA. 
 
 SCHOOL OF APPRENTICES AND JOUBHCYMCH 
 MCCHAHIQAL DRAWING 
 
 THE: ELLIPSE 
 
 SCALC Full Size CHVG.M,. CJOI4 
 
LESSON No. 20. 
 
 ENGINEERING CURVES. The principle of this lesson is to 
 generate the path oj a moi-ing point. The curves illustrated are con- 
 stantly used in engineering work, and a knowledge of their construction 
 should be both interesting and valuable to the student. 
 
 The cycloid is the curve generated by a point on the circumference 
 of a circle when rolled along a straight line. When the generating 
 circle is rolled upon another circle, an epicycloid will be generated. 
 
 When the generating circle is rolled under another circle, a hypo- 
 cycloid will be generated. 
 
 To generate the cycloid mechanically, lay off the base and center 
 lines; set the dividers to any short space (so that the length of the 
 chord is about equal to the arc), in this instance \ inch, ,and step off 
 16 or 18 points on the base line. Erect perpendiculars through these 
 points; swing in the generating circle from these different points, so as 
 to place the circle in the different positions which it would assume in 
 making one complete revolution. Now, with the dividers, step off on 
 the second circle the distance it has rolled along the base line, in this 
 ta>e } inch. Repeat for each new position of the generating circle 
 (measuring with the dividers the distance around the circle that it has 
 lolled along the base line), until a complete revolution has been made, 
 then trace the curve through the points thus found. 
 
 The epicycloid and hypocycloid are generated in the same manner, 
 
 the base circle replacing the base line of the cycloid. 
 
 The involute is the curve generated by every point in a cord as it 
 is wrapped upon or unwound from a cylinder. 
 
 To develop the involute mechanically, unwind a little bit of the 
 cord at a time, and step off upon the line the distance unwound. 
 
 Set the dividers to \ inch and step off 10 or 12 divisions upon the 
 base circle; from these points draw tangent lines to represent the cord 
 in different positions when being unwound. 
 
 The helix or screw is the curve which would be generated upon a 
 cylinder revolved at a constant speed against a point, the point moving 
 along at a constant speed parallel with the axis of the cylinder. 
 
 To generate this curve mechanically, divide the circumference of 
 the cylinder into any number of equal parts, in this case 25, numbering 
 these points from the left on the center line, as shown. Divide the pitch 
 distance on the cylinder into the same number of equal spaces (25) by 
 which the circumference of the cylinder was divided. 
 
 Now locate points on the side view of the cylinder at the intersec- 
 tion of the vertical division lines with the horizontal projection lines 
 (these lines being projected from the points on the end view of the 
 cylinder); then trace the curve through the points thus. formed. This 
 subject requires very accurate and careful work on the part of the 
 student. 
 
 OF THE 
 
 UNIVERSITY 
 
 OF 
 
Cycloid 
 
 Involute 
 
 Helix or Screw . P Pitch 
 
 CiAss Industrial TRAO Machinist 
 NAME John W.Roberts DATE Feb. 6.07. 
 
 THE CARNEGIE TECHNICAL SCHOOLS 
 
 f/TTSBUffSH, PA. 
 
 SCHOOL Of APPRENTICES AND 
 
 MECHANICAL DRAWING 
 
 ENGINEERING CURVES 
 THE PATH or A MOVING POINT 
 
 SCALC full Size 
 
 DWS.ua. C.IOIS 
 
 I 
 
LESSON No. 21. 
 
 SPUR GEAR. From Drawing C-ioi6 make a full-size pencil 
 drawing of the 24-tooth spur gear illustrated. 
 
 The student should study carefully the following memoranda, as 
 he is expected to make use of them in obtaining the sizes of teeth, 
 diameters of gear, etc. 
 
 If grooves are cut in the face of a smooth wheel, the parts between 
 the grooves are called lands. A part added to a land is called an ad- 
 dendum. A land and addendum together is a tooth. Between the 
 teeth are spaces. A toothed wheel is called a gear wheel, or simply a 
 gear. When the teeth of two gears e.ngage together, the gears are said 
 to be in mesh. Two or more gears in mesh are called a train of gears. 
 The circumference of the smooth wheel in which the grooves are cut 
 and to which the addenda are added is called the pitch circle. The 
 teeth of meshing gears should be so formed that their pitch circles roll 
 together without any slip. The word "diameter" when applied to 
 gears is understood to mean the pitch diameter, that is, the diameter of 
 the pitch circle. Diametral pitch of a gear is the number of teeth to 
 each inch of its pitch diameter. Circular pitch is the distance from 
 the center of one tooth to the center of the next tooth, measured along 
 the pitch circle. A gear blank is the wheel before the teeth have been 
 cut into it. 
 
 In modern practice the proportions of involute cut teeth are as 
 follows: The tooth thickness, T, is equal to the space, S. The adden- 
 dum, A, is equal to . _. , ; thus for 4 pitch the addendum 
 
 Diametral Pitch 
 
 is \ inch. The clearance is generally made one-eighth of the addendum 
 height; the depth, D, is equal to A, with clearance added. 
 
 The radius, R, at the root of the tooth is about one-sixth the dis- 
 
 tance B, but varies greatly. The rim thickness, C, is usually made 
 approximately equal to tooth depth. 
 
 USEFUL GEAR FORMULAS. Circular Pitch or 
 Diametral Pitch or D.P. = 3 ' I4I<5 
 
 Pitch Diameter= 
 
 CP 
 
 Number of teeth 
 DP 
 
 Distance between the centers of two gears =$ of 
 
 N+n 
 DP' 
 
 N= number of teeth in large gear; n= number of teeth in small gear. 
 
 Outside diameter of gear, or diameter of blank, = number of teeth 
 in gear+2-r-D.P. 
 
 The particular involute curve most generally used in gear teeth is 
 called the 15 involute. To construct it: Describe the pitch circle of 
 the required gear and draw a line tangent to it. At the tangent point, 
 draw a line at an angle of 15 to the tangent line. From the center of 
 pitch circle, draw a circle tangent to the 15 line; this is called the base 
 circle, and is the circle upon which the involute is generated. 
 
 When laying out the gear teeth, observe that the part of the tooth 
 inside of the base circle, or the flank, as it is generally termed, is a 
 radial line. It is necessary to lay out the involute curve but once, for 
 the student may set his compasses to a radius (which will be an approx- 
 imation to this curve), to throw in the faces of the other teeth. This 
 work requires the utmost care to obtain accurate results. 
 
 When pencil drawing is complete, make a good clear tracing. 
 
 Where the dimensions are not shown, the student is expected to use 
 the formulas given to obtain the necessary figures. 
 
True Involute 
 
 Addendum Circle 
 
 Pitch Circle 
 Base Circle 
 Poof Circle 
 
 CLASS Industrial TRADE Machinist 
 
 NAHIC John W. Roberts DATE Mar.20.-O7. 
 
 THE CARNEGIE TECHNICAL SCHOOLS 
 
 PITTSBURGH. PA. 
 
 SCHOOL OF APPRENTICES AND JOURNEYMEN 
 MECHANICAL DRAWING 
 
 SPUR GEAR 
 
 SCALE Full Size 
 
 oiva. NO. C. 1016 
 
LESSON No. 22. 
 
 INTERSECTIONS. The important principle contained in this 
 lesson is the projection of a point. 
 
 From Drawing C-ioiy, make a full-size pencil drawing of the 
 intersecting cylinders and their developments. 
 
 The curve formed by the intersection of the two cylinders is found 
 point by point as shown by points 2 and 4 on the illustration. The 
 oval shown in the end view is formed by cutting the large cylinder off 
 at an angle of 30 with the horizontal plane; it is found in the same 
 manner as the curve of intersection. " 
 
 If the student studies the illustration carefully, he should be able to 
 follow out the method of projecting a point from one view to 
 another. 
 
 As the end views of the cylinders are the only views on which the 
 true circumference can be obtained, it naturally follows that it is the 
 end view in each case that should be used to locate the division points. 
 
 The circumference of the cylinder may be divided into any num- 
 ber of points, and those points projected upon the other views to obtain 
 the desired curves. 
 
 DEVELOPMENT. The student should try to realize that a sur- 
 face is composed of a series of lines. 
 
 The different methods of developing a surface are usually described 
 by the kinds of 'lines used for this purpose. As an instance, in our 
 present lesson we use parallel lines to develop the surfaces of the 
 cylinders. 
 
 If we were to cut the large cylinder through at point C, and were 
 then to spread it out flat, we would have a duplicate of the' develop- 
 ment of the large cylinder shown. 
 
 For the reasons given above, the end view of the cylinder is the 
 proper place to obtain the true length of the development, assuming 
 that the student is unable to find the circumference by simple arith- 
 metic. 
 
 The lengths of the various lines used in developing the surface of 
 the pattern may be obtained from the side view. 
 
 It is very desirable that each student should make a careful study 
 of this subject, as a thorough knowledge of the principle involved will 
 be of value when drawing difficult shapes. 
 
 OF THE 
 
 UNIVERSITY 
 
 OF 
 -IFQR^ 
 
I S 3 4 5 6 7 a S 10 II IS 
 
 c d e f g h j k m n a b c 
 
 CLASS Industrial TRADE Machinist 
 
 NAME John W.Roberts DATE April 2O-O7. 
 
 THE CARNEGIE TECHNICAL SCHOOLS 
 
 PITTSBURGH, 'PA. 
 
 SCHOOL or APPRENTICES AND JOURNEYMEN 
 
 MECHANICAL DRAWING 
 
 INTERSECTIONS AND DEVELOPMENTS 
 PARALLEL LINE DEVELOPMENT 
 
 SCALE full Size DUG. NO. C.I 017 
 
LESSON No. 23. 
 
 INTERSECTIONS. From Drawing C-ioi8, make a full-size 
 pencil drawing of the intersecting cone and cylinder and their develop- 
 ments. 
 
 If the student has fully mastered the previous lesson on intersections, 
 he should be able to develop the curves of intersection shown in the 
 top and front views of the present lesson. These curves are found in 
 the same manner as those of the intersecting cylinders; that is, point 
 by point. 
 
 The student may divide the end of the cylinder into any number of 
 points, then draw radial lines through these points. Or he may draw 
 the radial lines first, and then place points at the intersections of the 
 lines with the end of the cylinder, as shown by points i and 4. 
 
 The latter method is the one used in the illustration, and the stu- 
 dent should observe that to project these points i and 4, it is first 
 necessary to have the radial line 1-4 projected upon the top 
 view. 
 
 RADIAL-LINE DEVELOPMENT. In our last lesson the sur- 
 faces of the figures were composed of parallel lines, the method of 
 development being named from the kind of lines used. 
 
 In our present lesson we find it necessary to use radial lines to 
 develop the surface of the cone, from which this method derives the 
 name of "Radial-line Development." 
 
 When laying out the development of the cone, the student must 
 bear in mind that the true length of the lines on the cone can be found 
 on the sides of the cone only, as in all other positions the lines are fore- 
 shortened. Thus to get the true distance from the apex of the cone 
 to point i, this point must be projected to one of the sides. 
 
 The length of the arc of the development is equal to the circum- 
 ference of the base of the cone. 
 
 The radial lines used in finding the intersections are also used in 
 locating the opening in the development. 
 
 Do your work very carefully. 
 
THE CARNEGIE TECHNICAL SCHOOLS 
 
 CLASS Industrial TRADE Machinist 
 
 NAME John W.Roberts DATE April 26,07. 
 
 PITTSBURGH. PA 
 
 or APPRENTICES AND 
 MECHANICAL DRAWING 
 
 INTERSECTIONS AND DEVELOPMENTS 
 RADIAL LINE DEVELOPMENT 
 
 SCALE Full Size 
 
 owe. /vo. C. IO IB 
 
LESSON No. 24. 
 
 TRIANGULATION DEVELOPMENT. Upon a B-size sheet 
 of drawing paper (i5"X22"), make a full-size pencil drawing of the 
 Transition Piece and its development. 
 
 Sheet-metal workers require a great many patterns which cannot 
 be laid out to good advantage by either the Parallel- or Radial-line 
 methods of development. 
 
 These patterns may usually be laid out by dividing the surface of 
 the figures into a series of triangles, from which this method gets the 
 name " Triangulation Development." 
 
 LESSON. First lay out the two views of the piece illustrated, 
 marking them with letters and figures as shown. Then find the true 
 length of each of the slope lines ABCD, etc. These lengths may be 
 found in the manner indicated on the illustration, which the student 
 should be able to understand without help. 
 
 Now, using these lines with the top and base lines, construct the 
 triangles into which the figure had been previously divided. Connect 
 these triangles in the manner indicated by the partial development, 
 and the result will be the complete pattern desired. 
 
b 
 
 True length 
 
 CLA33 Industrial TRADE: Machinist 
 
 John W.Roberts DATE May ff,O7. 
 
 THE CARNEGIE TECHNICAL SCHOOLS 
 
 PITTSBURGH, PA. 
 
 SCHOOL or APPRENTICES AND JOURNEYMEN 
 
 MECHANICAL DRAWING 
 
 INTERSECTIONS AND DEVELOPMENTS 
 TRIANCULATION DEVELOPMENT 
 
 SCALE Pull Size OWG./VO. i 
 
LESSON No. 25. 
 
 VALUE OF PRACTICE. From the previous lessons the stu- 
 dent should have become familiar with the general principles of 
 mechanical drawing. With this assumption in mind, the main 
 requirement of the student is now to obtain sufficient practice, making 
 detail and assembly drawings, to help him to become proficient in 
 turning out rapidly work that is accurate, with the lettering and dimen- 
 sioning done in a neat and attractive manner. 
 
 No modern drafting room will send out blue prints of drawings 
 upon which the lettering has been poorly done, or the dimensions of 
 which are indistinct. Many a young draftsman has been refused em- 
 ployment simply because he was a poor letterer. If the applicant's 
 sample drawing is neatly lettered and dimensioned, the chances are 
 that he will be given an opportunity to show what he can do. 
 
 The student is expected to do the very best work he is capable of, 
 on the following working drawings. 
 
 DETAIL DRAWING. The present lesson is a quarter-size 
 detail drawing of the lathe leg shown on Drawing C-ioao. Make a 
 
 tracing of the finished pencil drawing. 
 
 The student will observe that the metal of the side Of the leg is 
 J inch thick near the back, and that it tapers down to J inch at the 
 front edge. This is shown in the top view, and is for two purposes: 
 To make the casting light but strong, and also to allow the pattern to 
 be easily lifted out of the sand when making molds in the foundry. 
 
 The openings in the back of the leg are for the purpose of making 
 the casting lighter. The J-inch rib around these openings strengthens 
 the casting without adding much weight. 
 
 To throw in the large radii given, the student will find it necessary 
 to use a beam compass, as these radii are too long for the ordinary 
 compass, even though the extension bar were used. 
 
 In most drafting rooms a mark of some kind is used on the draw- 
 ings to indicate that a surface is to be finished, that is, machined in the 
 shop. The "finish mark" shown on the present lesson is adopted 
 from the Universal Dictionary of Mechanical Drawing by Prof. G. 
 H. Follows 
 
s~jg3to 
 
 fj Holes 
 
 BILL OF MATERIAL 
 
 Description and Mafer/al 
 
 Paf. No. 
 
 7O 
 
 Peq. 
 
 is Holes in -feet 
 Section A-B 
 
 Industrial TRADE Machinist 
 John W. Roberts DATE: May fl- 07. 
 
 THE: CARNEGIE TECHNICAL SCHOOLS 
 
 PITTSBURGH, PA. 
 
 SCHOOL. Of APPRENTICES AND JOURNEYMEN 
 
 MECHANICAL OfAWIMG 
 
 2 SPEED LATHE 
 LEG DETAILS 
 
 SCALE: j- Size 
 
 Dwa.fJo.C-/OfO 
 
LESSON No. 26. 
 
 LATHE BED. Make a half-size pencil drawing of the lathe bed 
 shown on drawing C-iozi. Make a tracing of the finished pencil 
 drawing. 
 
 This drawing shows the method commonly used to take care of 
 pieces which are too large for standard-size sheets; this method is to 
 show the piece " broken, " as it is termed. 
 
 The lathe bed shown is five feet long, and to show it without " break- 
 ing," or the complete bed, would necessitate that it be drawn to a very 
 small scale, so small, in fact, that the views would not show to the best 
 advantage what the drawing was intended to show. 
 
 By breaking away part of the bed, we are able to draw it to a larger 
 scale and show more clearly its shape and size. The part broken 
 away is of no value to any one using the drawing, as it is similar to the 
 rest of the bed adjoining the break. 
 
 Observe carefully all notes and dimensions, and see that none are 
 overlooked, as full information must be furnished on working drawings. 
 
 The cap screws referred to in the "Bill of Material" are for bolting 
 the legs to the bed. 
 
 The broken views of the top and bottom of the bed are intended 
 to show more clearly the shape of the corners, the sizes of fillets, and 
 to show the position of bolt holes. 
 
 The student should refer to the leg drawing, -1020, if he desires 
 to see whether the positions of the clearance holes in the top view of 
 the leg correspond to the tapped holes in the bottom of the bed. 
 
 Observe the method of using the "finish mark" shown at the top 
 of the end view. This indicates that the whole surface between marks 
 is to be finished. 
 
Drill g dia^deep 
 Tap g-!6Thds. 
 
 No. 
 
 Description and Material 
 
 Pat. No. 
 
 Req. 
 
 S 
 
 Bed C.I. 
 
 71 
 
 I 
 
 i 
 
 ix/i'Hex.Hd. Cap Sc. 
 
 
 a 
 
 Industrial TWXDC Machinist 
 
 NAME John W.Roberfs DATC May 10-07. 
 
 THE CARNEGIE TECHNICAL SCHOOLS 
 
 PITTSBURGH, PA. 
 
 SCHOOL or APPRENTICES ANO JOURNEYMEN 
 
 MECHANICAL DRAWING 
 
 12 
 
 SCALE 75 Size 
 
 LATHE: 
 DETAILS 
 
 OWG.HO. C.I OS I 
 
LESSON No. 27. 
 
 TOOL-REST DETAILS. Most of the parts or details of a 
 speed-lathe tool rest are shown on Drawing -1022; part of these 
 details are drawn half size, and the rest full size. 
 
 Make an accurate pencil drawing and tracing of the details shown. 
 
 The hand wheel is very similar to one drawn in an earlier lesson, 
 with the exception that it is an "offset" wheel, that is, the rim is not 
 central over the arms, but set to one side. The necessary radii with 
 the location of their centers are shown, so that the student should be 
 
 able to draw this hand wheel without difficulty. 
 
 When drawing the arms of the hand wheel, bear in mind what was 
 said in the earlier hand-wheel lesson, in regard to using a straight line 
 for the purpose of joining two curves. 
 
 Do not overlook any of the dimensions on the various details, for 
 you must remember that you are furnishing the man in the shop with 
 the necessary information to machine these parts correctly. 
 
 Use great care with the lettering and figures. 
 
Finish all over- 
 
 f?ivef 
 
 Harden 
 
 CLASS Industrial TffAOC Machinist 
 
 NAME John W.Roberts DATE Dec. /cl.07. 
 
 77VE CARNEGIE TECHNICAL SCHOOLS 
 
 PITTSBURGH PA. 
 
 SCHOOL or APPITENTICCS AND JOURNEYMEN 
 
 MECHANICAL DRAWING 
 
 12 SPEED LATHE: 
 TOOL REST DETAILS 
 
 & Full Size owe.No. C-/02e 
 
LESSON No. 28. 
 
 TOOL-REST ASSEMBLY. Drawing -1023 is an assembly 
 drawing of the complete tool rest. 
 
 This drawing is used for the purpose of showing how the different 
 parts are fastened together, or assembled, as it is termed. 
 
 The only parts dimensioned are the stand and clamp, all of the 
 other details being machined from Drawing -1022. This assembly 
 drawing is, therefore, used as a detail drawing also, as the stand and 
 clamp may be machined from it. 
 
 When drawing the parts that are not dimensioned, the student must 
 necessarily refer to the detail drawing to obtain the sizes needed. 
 
 Study the drawing carefully so as to obtain a clear understanding 
 of the meaning of each line. Do not simply copy the various lines 
 because they are shown on the original; satisfy yourself as to their 
 meaning. 
 
 Think for yourself. 
 

 
 J- /" 
 
 
 
 a l 
 
 
 
 
 
 
 
 
 
 r /V" 1 
 
 
 
 ' 
 
 
 
 -. X 
 
 
 
 '__ _^_^- 
 
 
 
 
 
 
 
 
 
 
 N\fiw 
 
 Drills-Tap ^'-16 Thds. 
 
 ) 
 
 BILL or MATERIAL 
 
 Detail of Stand 
 
 Hem 
 No. 
 
 Description and Material 
 
 Pat. No. 
 
 Req. 
 
 (JJ 
 
 Tool Rest. C.I. 
 
 79 
 
 1 
 
 
 
 - Stand, C. 1. 
 
 80 
 
 I 
 
 1 
 
 Base, C.I. 
 
 81 
 
 1 
 
 
 
 - Hand Wheel, C.I. 
 
 82 
 
 1 
 
 i 
 
 Clamp, W. 1. 
 
 
 1 
 
 i 
 
 Clamp Bolt, W. 1. 
 
 
 1 
 
 
 
 Adjusting Screw, C.R. 
 
 
 1 
 
 r 
 
 Adj. Screw Lever, C.R. 
 
 
 1 
 
 CLASS Industrial TRADE Machinist 
 
 f 
 John W. Roberts r>ATc Dec.P4.O7. 
 
 THE CARNEGIE TECHNICAL SCHOOLS 
 
 PITTSBURGH, PA. 
 
 SCHOOL or APPRENTICES AND JOURNEYMEN 
 
 MECHANICAL D?4WfNG 
 
 /<? SPEED LATHE. 
 TOOL REST A SSEMBLY 
 
 SCALC ->5 Size 
 
 OIVG. NO. C. IO2-3 
 
LESSON No. 29. 
 
 TAILSTOCK DETAILS. Part of the details of a lathe tailstock 
 are shown on Drawing -1024. 
 
 The sectional view of the spindle shows the taper bore in one end, 
 and the method of fastening the bronze nut in the other end. 
 
 The end of the spindle is bored to a taper of f inch per foot, or the 
 "Morse Taper," a name by which this particular taper is known in 
 shops and drafting rooms. By a taper of f inch per foot, we mean 
 that a cylindrical piece 12 inches long and i inch in diameter at the 
 small end will be if inches in diameter at the large end. In other 
 
 words, the piece is f inch larger in diameter at one end than at the 
 other. 
 
 By this time the student should be sufficiently familiar with hand 
 wheels to need no instruction on this subject. 
 
 The binding screw shown is an illustration which shows the value 
 of a knowledge of shop practice. This screw is machined in a lathe 
 in the manner shown by the solid lines; after being finished, it is placed 
 in a special forming tool, where it is bent to the shape shown by the 
 dash lines. Make a tracing of the finished pencil drawing. 
 
Not? Morse Taper 
 
 
 
 '. per 'in. 
 
 Ci/<ss Industrial TRADE Machinist 
 NAME John W.Roberts DATE Dec. JO- 07. 
 
 THE CARNEGIE TECHNICAL SCHOOLS 
 
 PITTSBURGH. PA. 
 
 SCHOOL OF APPRZNTICES AND JOURNEYMEN 
 MECHANICAL DRAWING 
 
 IS SPEED LATHE 
 TAILSTOCK DETAILS 
 
 SCALE full Size owa. o. C_ IOS4 
 
LESSON No. 30. 
 
 TAILSTOCK DETAILS. The rest of the details of the lathe 
 tailstock are shown on Drawing 0-1025. 
 
 The small spindle key is used to prevent the spindle from revolving. 
 
 The square-thread screw is used to move the spindle in and out of 
 the tailstock barrel. The manner in which the thread is shown on 
 this screw indicates that it is to be cut the full length to the collar. 
 The main object in showing the thread in this manner is to save the 
 draftsman's time. 
 
 The small key set into the stem of the screw is known as a Wood- 
 ruff key. This key resembles a portion of a washer driven into a slot 
 
 milled in the screw. 
 
 From the rules given in a previous lesson, the student can obtain 
 the dimensions necessary to draw the hexagon nut. 
 
 The wrench shown is used to tighten the nut on the clamp bolt, 
 thus fastening the tailstock to the bed. 
 
 The tailstock plug, or bell, as it is usually termed, supports the 
 spindle screw. 
 
 The small steel oiler is used to drop oil on the centers. Make a 
 pencil drawing and tracing of this lesson. Do the very best work you 
 are capable of. 
 
 F i 
 
 UNIVERSITY 
 
-to 
 
 to 
 
 U? 
 
 
 IS 
 
 '6 ~ 
 
 -- rr -* 
 
 
 
 
 I 
 
 
 
 ~J J 
 
 j"-^ 
 
 jfe 
 
 
 ^ -> 
 
 1 ' <? /"//" TV -J 1 
 
 Itllf 
 
 
 J * 
 
 
 
 
 1 s 
 
 J l<lj x- ^^ ''"-' 
 
 ffi 
 
 
 x lAj 
 
 
 j 
 
 J 
 
 I V 
 
 t 
 
 
 
 t 
 
 
 /. 
 
 1 
 
 g J 
 
 W- 
 
 / 
 /6 Thd.per in. 
 
 r* 
 
 i_r^ 
 
 t * 
 
 CLASS Industrial T/TADC Machinist 
 
 NAME John W.ffoberfs OATC Jan. 6- OB. 
 
 THE CARNEGIE TECHNICAL SCHOOLS 
 
 QH, PA. 
 SCHOOL or APPRENTICES AND J 
 
 MECHANICAL. &PAWM 
 
 //? SPEED LATHE: 
 TAILSTOCK DETAILS 
 
 SCALC rull Size 
 
 DWB.No. C-1025 
 
LESSON No. 31, 
 
 TAILSTOCK ASSEMBLY. Drawing -1026 shows the tail- 
 stock completely assembled, with all the details numbered to corre- 
 spond with the numbers in the "Bill of Material." 
 
 Where dimensions are not shown on certain parts, the student is 
 expected to refer to the detail drawings for the necessary informa- 
 tion. 
 
 The saw cut on the side of the tailstock barrel is for the purpose of 
 
 allowing this part to clamp tightly around the spindle when the bind- 
 ing screw is tightened down. 
 
 The oil hole shown in the bell should be drilled after it is in place 
 in the barrel, as it should of necessity be on the upper side of the bell. 
 
 Make this drawing and tracing very carefully; do not overlook any 
 dimensions or notes. Bear in mind that nothing is good enough but 
 the best work you are able to do. 
 
**--;-= -p* * = =.-=i--r-_-s.-=.i.-fs.-B. = --^a-^ s.-s.*^i 
 
 hole 
 
 Bore l Tap I$-I2 Thd. 
 
 BILL or MATERIAL 
 
 Note: For details see Dwgs. CJO24 & C./OP5 
 
 //<?//? 
 
 A/o. 
 
 Description and Material 
 
 Pat. No. 
 
 Req. 
 
 s 
 
 Tailstock, C.I. 
 
 76 
 
 I 
 
 1 
 
 Spindle, Corona Steel 
 
 
 1 
 
 i 
 
 Screw C.R. with j'Hex. Nut. 
 
 
 / 
 
 i 
 
 Bell, C.I. 
 
 77 
 
 I 
 
 i 
 
 Hand Wheel. C. 1. 
 
 78 
 
 1 
 
 i 
 
 Dead Center, Tool Steel 
 
 
 1 
 
 a 
 
 Spindle Nut, Bz. 
 
 
 1 
 
 $ 
 
 X? Woodruff Key, C.R. 
 
 
 1 
 
 | 
 
 /} Washer, C.f?. 
 
 
 1 
 
 @ 
 
 ,fXitxj? Spindle Key, C.R. 
 
 
 1 
 
 
 
 Oiler. C.R. 
 
 
 1 
 
 i 
 
 Binding Screw, C.R. 
 
 
 1 
 
 1 
 
 f~X6 Clamp Bolt with Hex.Nut 
 
 
 1 
 
 s 
 
 Clamp , W. 1. 
 
 
 I 
 
 CLASS Industrial T/MOC Machinist 
 HAMcJohn W. Roberts DATE Jan. I - 
 
 THE CARNEGIE TECHNICAL SCHOOLS 
 
 PITTSBURGH, PA. 
 
 SCHOOL or APPRENTICES AND JOURNEYMEN 
 
 MECHANICAL DRAWING 
 
 12 SPEED LATHE 
 TAILSTOCK ASSEMBLY 
 
 Size 
 
 owe. NO. C.I026 
 
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 Andre, Geo. G. The Draughtsman's Hand Book of Plaa and Map 
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 Cryer, T' an .d Jordan, H. G. Machine Construction and Mechanical 
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 course of Instruction for the Practical Engineer. Illustrated by 
 numerous engravings, 4to, half mor. 10.00 
 
 Fox, Wm. and Chas. W. Thomas. A Practical Course in Mechan- 
 ical Drawing. Being a course of progressive lessons illustrated with 
 many diagrams and figures. Especially adapted to use of schools, col- 
 leges, etc. Second edition revised. 12mo, cloth, 1-25 
 
 The object of this work is to provide a simple, practical course of 
 progressive lessons in Mechanical Drawing. All instructions are given 
 in connection with a special concrete exercise, instead of being pre- 
 sented in an abstract and general manner. 
 
 Heather, J. F. Mathematical Instruments; their Construction, Ad- 
 justment, Testing, and Use, Comprising Drawing, Measuring. Optical, 
 Surveying, and Astronomical Instruments. Enlarged edition, for the 
 most part re-written. With numerous diagrams and figures. 12mo, 
 
 cloth 1-80 
 
 Minifie, Wm. Mechanical Drawing. A Text-Book of Geometrical 
 Drawing, for the use of Mechanics and Schools, in which the Defini- 
 tions and Rules of Geometry are familiarly explained ; the Practical 
 Problems are arranged from the most simple to the more complex, 
 and in their descriptions technicalities are avoided as much as possible. 
 With illustrations for Drawing Plans, Sections and Elevations of 
 Buildings and Machinery ; an Introduction to Isometrical Drawing, and 
 an Essay on Linear Perspective and Shadows. Illustrated by over 
 200 diagrams, engraved on steel. With an Appendix on the Theory 
 and Application of Colors. 8vo, cloth, (Ith thousand 4.00 
 
 Rauteiistrauch, W., and Williams, J. T. Machine Drafting 
 and Empirical Design. A Text-book for Students in Engineering 
 Schools. Part I on Machine Drafting. 8vo, cloth, 70 pp net, 1.25 
 
 Keinhardt, C. W. Lettering for Draftsmen, Engineers, and 
 Students. A Practical System of Freehand Lettering for Work- 
 ing Drawings. Revised and Enlarged. Twenty-sixth Thousand. 
 Oblong Boards 1.00 
 
 Kipper, William. A course of Instruction in Machine Drawing 
 and Design for Technical Schools and Engineer Stmlc-nis. \Villi '<^ 
 plates and numerous explanatory engravings. Folio, cloth 0.00 
 
 Rose, Joshun.- Mechanical Drawing Self-Taught. Comprising In- 
 structions in the Selection and Preparation of Drawing Instruments, 
 Elementary Instruction in Practical Mechanical Drawing, together 
 with Examples in Simple Geometry and Elementary Mechanism. 
 including Screw Threads, Gear Wheels, Mechanical Motions, Engines 
 and Boilers. Illustrated. 8vo, cloth 4.00 
 
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