STRVCTVRAL DRAWING C.F.EDMINSTER LIBRARY OF THE UNIVERSITY OF CALIFORNIA. Class STRUCTURAL DRAWING BY C. FRANKLIN EDMINSTER INSTRUCTOR IN DEPARTMENT OF FINE AND APPLIED ARTS, PRATT INSTITUTE, BROOKLYN, NEW YORK. FIRST EDITION, PUBLISHED BY THE AUTHOR. StNtHAt COPYRIGHT, 1907, BY C. FRANKLIN EDMINSTER. PREFACE. IN preparing this work, the author has aimed to present to the mechanic and others who are interested, a systematic course of instruction in structural drawing, beginning with the standard forms and leading to the typical columns, girders, trusses, and framing details. The drawings are made as simple as possible, and many isometric views are given to further as- sist in reading and understanding the subject. A few problems in geometry and projection have been introduced for the benefit of those who have not studied drawing: also a short chapter covering the general notes on drawing materials. The student should begin with the first plate and follow in the order given, mastering each prob- lem in succession. C. FRANKLIN EDMINSTER 174531 CONTENTS. CHAPTER PAGE I. Notes on Materials 7 II. Geometrical Problems - 13 III. Simple Projection. Introducing the Prin- ciples of Working Drawings - - 24 CHAPTER IV. Structural Details - V. Steel Mill Construction VI. Iron Staircase Construction PAGE 38 1 08 132 ABCDEFGHIJKLMNOPQRSTUVWXYZ ABCDEFGHIJKLMNOPQRSTUVWXYZ a bcdefg hij klmnopqrstuvwx LJ z CHI L XY 12 34567890 STRUCTURAL DRAWING. CHAPTER I. NOTES ON MATERIALS. THE student beginning the study of struc- tural drawing should provide himself with the necessary instruments of a good quality. He should not be hampered by using inferior ma- terials, as many difficulties will arise under even the best conditions. Drawing Boards. One of the best methods of making a drawing board is to glue together narrow strips of boards, fastening two cleats (about two inches wide) across the back in such a way that there will be perfect freedom for the wood to expand and contract, which it surely will do as the humidity of the atmos- phere changes. This freedom may be obtained by cutting slots in the cleats through which the screws pass and placing iron washers under the heads of the screws. A much cheaper board can be constructed by securing narrow pieces across each end, which serve to hold the board from warping. This form of board will answer very well, especially if the paper used is not stretched. It is extremely important that one end and one side of the board should be per- fectly straight. Drawing Paper. Drawing paper that is to be used for general draughting and line work in pencil or ink should have a firm, smooth surface that is not easily roughened when era- STRUCTURAL DRAWING. sures are made. As a rule, paper that is well adapted to line work will not receive a flat wash readily. Paper suitable for wash drawings is made with a surface less firm but rougher than for line work. Whatman's cold pressed paper possesses unusual properties, in that it works well for both line and wash drawings. For general detail work, some of the tinted papers are more pleasant to work upon than white, as the white is rather trying to the eyes, especially when used in the evening. For highly finished drawings, however, white paper is gen- erally preferred. The right side of the paper can usually be determined by holding it to the light and finding the water-mark, which should read correctly on the side used. Drawing paper may be obtained in sheets of standard sizes as follows: Cap, i3"xi;"; Demy, 15" x 20"; Medium, i7"x22"; Royal, I9"x24"; Super Royal, 19" x 27"; Imperial, 22"x3o"; Ele- phant, 23" x 28"; Atlas, 26" x 34" ; Double Elephant, 27"x4o"; Antiquarian, 3i"x53"; Emperor, 48" x 68". The above terms apply only to the sizes of the sheets, and not in any way to grade or quality of the paper. T-Square. The T-square is made of two parts, the head and blade, which are fastened together at right angles to each other. This instrument should be used for drawing horizon- tal lines only, always holding the head against the left-hand edge of the board. Should the draughtsman allow himself to use either left or right side of the board at will, the results ob- tained would be very inaccurate, owing to the fact that two ends or sides of the board are sel- dom, if ever, parallel. Again, many times the T-square blade does not form right angles with the head. One may readily see that horizontal lines drawn under such conditions would not be parallel. Triangles. The draughtsman should provide himself with two triangles ; the 45, and the 30 and 60. The triangles are used for draw- ing all lines that are not horizontal. Vertical STRUCTURAL DRAWING. lines should always be drawn by placing the tri- angle on the upper edge of the T-square blade, holding the pencil or pen in a plane perpendic- ular to the surface of the paper, inclining it slightly, and drawing upward, but never down- ward. In drawing horizontal lines, the pencil or pen should be held in a plane perpendicular to the paper, inclining it slightly to the right. Draw from left to right. Angles of 45, 30, 60 and 90, with a horizontal line, can be drawn at once by placing the triangle on the T-square blade. Instruments. Instruments should be selected with the greatest care. It is much better to have a few pieces of excellent quality than a great number of inferior make. Choose qual- ity rather than quantity. Instruments should be well cared for, properly wiped each time after using, and the points prevented from con- tact with hard substances which will tend to in- jure them. Compasses. When drawing with the com- passes the head should be held lightly between the thumb and two fingers, moving the leg con- taining the lead in the direction traversed by the hands of a clock, inclining it slightly in the direction of the line to be drawn. The joints in the legs should be so adjusted as to keep the lower sections perpendicular to the surface of the paper, and when a circle is of such a size as will not admit of this the lengthening bar should be inserted. Ruling Pen: The ruling pen is a very impor- tant instrument and should be made of the very best hardened steel ; if not, it will give the stu- dent endless trouble. Most of the prepared inks in general use are provided with a quill in the cork of the bottle which lifts a certain amount of ink. The quill may be inserted be- tween the nibs of the pen and the ink allowed to flow into the pen. The ink should not be more than one-fourth of an inch deep between the nibs. Clean the pen frequently by immers- ing it first in clear water and then passing a STRUCTURAL DRAWING. piece of cloth or chamois skin between the nibs. The pen should never be put away after using without being thoroughly cleansed. Pencil. The character of the work performed by a student is generally influenced by the condition in which he keeps his pencil. It is impossible to do accurate work with a dull pen- cil. For all rule work the wedge-shaped point possesses an advantage over the round point, in that it has a greater wearing surface, hence will not require sharpening so often. For all freehand work nothing but the round or con- ical point should be used. Some draughtsmen prefer this point for rule work as well. The wood should be cut well back, leaving at least one-fourth of an inch of the lead exposed. One of the best sharpeners for a pencil is a fine flat file, on which the lead should be frequently applied, to produce a sharp point. Where great accuracy is required, the beginner should use a 4 H pencil. As skill in draughting is acquired, a softer grade may be substituted. A medium grade pencil should be used for lin- ing-in the drawings where strength of line is required. The Scale. A scale is an instrument used in reducing a drawing that would otherwise be too large for the sheet of paper on which it is to be placed. For instance, if we have a building measuring 40 x 60 ft., the drawing may be made on a scale of Vt, of an inch to i ft. The space occupied upon the plate would be 10 x 15 in., exactly in proportion to the actual size. In using this scale, or proportion, we have taken an actual % of an inch and considered it i ft. ; and this being taken as i ft. we divide it into 12 parts, each part being equal to i in. There will be found several different scales upon the instrument, all of which are divided in a similar manner. Irregular Curve, This instrument is used in drawing curves that cannot be accomplished by the use of the compass. Such curved lines usu- ally pass through a succession of points which STRUCTURAL DRAWING. II have already been found. The edge of the ir- regular curve should be so placed (by repeated trials) as to pass through as many points as pos- sible and also a portion of the line already drawn. Never draw through the last point covered by the irregular curve. This operation requires a great deal of care in order to produce a per- fectly smooth curve. Penciling, Too much stress cannot be placed upon the first penciling of a drawing. All draw- ings, whether to be inked-in or left in a strong pencil line, should first be worked out with a light line and very accurately placed. Many students have the feeling that they can correct the little errors while lining-in the drawing ; this is not so, the chances being that they will greatly increase rather than diminish the faults. Inking. For highly finished drawings the stick India ink is generally preferred, but for ordinary work the prepared will be found satis- factory. The great advantage that stick ink possesses over the prepared is, that in case of error the line can readily be removed with the ordinary eraser. The disadvantage in using the stick ink is that considerable time each day is required to grind a fresh supply. In inking a drawing the student should ink all circles and arcs of circles first, then, beginning with the upper horizontal line, ink in order those below. With the vertical lines, begin on the left side of the plate and ink each line in succession. When several lines meet at a point always begin to ink from that point, allowing each successive line to dry before drawing another, thus pre- venting a blot that would otherwise occur at their junction. Visible Lines. The visible lines of an object are represented by a full black line. Invisible Lines. Invisible lines or lines that are hidden are represented by a dash line, the dashes being about one-quarter of an inch long, the spaces between them being less than one- eighth of an inch. This line should be of the same strength as a visible line. 12 STRUCTURAL DRAWING. Working Lines, Working lines are used to obtain certain results, and if left in pencil should be very light, or if shown in ink, should be very light red or short dash black lines. Arrow Heads. Arrow heads should always be in black and made with great care, their points just touching the line to be measured. Dimensioning. In placing the dimensions it is always well to group as far as possible and not scatter them over the entire drawing. As a rule the same measurement should not appear in more than one view. The measurement line upon which the dimension is placed should not be drawn too near the line measured, usually about one-quarter of an inch away. It is cus- tomary to place all dimensions over twelve inches, as feet and inches, thus: 5'-6" (five feet and six inches), or if in even feet, thus: 3'-o"(three feet and no inches). When the space between two lines is not sufficient to place the measurements in the usual manner they may be placed thus : Horizontal measurements should ft read from left to right, an d vertical \J 'lObv^ * * measurements should read up- ward. Great care should be taken in making figures, as the worth and appearance of the draw- ing depend greatly upon them. CHAPTER II. GEOMETRICAL PROBLEMS. Prob. J. To bisect a given straight line A B. FROM points A and B as centers and with any radius greater than half of the line A B, describe arcs above and below, intersecting in points i and 2. Draw a straight line through points i and 2, cutting the line A B at 3, thus bisecting the given line A B. Prob. 2. To bisect an arc of a circle A B. From a point A as center and with any ra- dius greater than half of curve A B, draw arcs above and below. With B as center and the same radius, cut the arcs already drawn in points i and 2. Draw a straight line through points i and 2, intersecting the curve A B in 3, which will bisect the given arc A B. Prob. 3. To bisect a given angle ABC With B as center and any radius, draw an arc cutting the lines B A and B C in points i and 2. With points i and 2 as centers and any radius greater than half of arc i - 2, describe arcs intersecting in point 3. Draw a line through points B and 3 which will bisect the given angle ABC. Prob. 4. To trisect a given right angle ABC With B as center and any radius, draw an arc cutting the sides of the right angle in points STRUCTURAL DRAWING. i and 2. With points i and 2 as centers and the same radius, draw arcs cutting in 3 and 4. Draw lines B 4 and B 3 which trisect the given right angle ABC. Prob. 5. To divide a given straight line A B into 6 equal parts (applicable for any number) . Draw the line A C at any angle to A B ; lay off on this line 6 divisions, each equal to about | of A B. Connect points 6 and B by a straight line. From points i, 2, 3, 4 and 5, draw lines parallel with 6 B cutting A B in a, b, c, d and e. Prob. 6. To divide line A B into the same proportional parts as the given line C D. From point A draw a line at any angle to A B. Lay off on this line the points correspond- ing to points on line C D. Connect points 4 and B. From points i, 2 and 3, draw lines parallel with 4 B, cutting the line A B in a, b and c. Prob. 7. To divide a circle having the center given, into 6 equal parts. Draw the diameter 1-5. With points i and 5 as centers and radius 1-2 describe arcs cutting the circle in points 3, 4, 6 and 7, which, with points i and 5, are the desired divisions. Prob. 8. From point A above the given line B Q draw a perpendicular to B C With point A as center and any radius, cut B C in i and 2. With i and 2 as centers and any radius, draw arcs below. From A draw a straight line to point 3, which is the desired perpen- dicular. Prob. 9. On a given line A B to erect a perpendic- ular at point A. With point A as center and any radius, draw an arc cutting A B in i. With i as center and the same radius, lay off points 2 and 3. With points 2 and 3 as centers and any radius, describe arcs above, cutting in 4. Connect points 4 and A, thus erecting the desired per- pendicular. Prob. JO. To draw a line C D parallel to a given line A B at a given distance, as E F above it. Erect perpendiculars at points i and 2 by Prob. 9, lay off on these the distance E F, giv- Plate i. PHOH.I. 'X PROB.. PROB.5. -3* PROB. 4 PROB. 8. PROB. 6. /I \ \ \ b o PROB. S. A ^-c i6 STRUCTURAL DRAWING. ing points 3 and 4. Draw line C D through 3 and 4. Prob. 1 1. Through point C draw the line D E paral- lel to A B. With point C as center and any radius, de- scribe an arc cutting A B in i. With i as cen- ter and same radius, describe an arc which will cut line A B in 2. With i as center and radius C 2, describe an arc cutting 1-3 in 3. Draw a straight line through points 3 and C, which will be the required line D E. Prob. 12. To construct an angle equal to a given angle BAG. Draw the line D F. With A as center and any radius, describe an arc cutting the sides of the angle in points i and 2. With D as center and the same radius, describe an arc cutting D F in 3. With radius 1-2, and 3 as center, de- scribe an arc cutting 3-4 in 4. Draw D E through 04. E D F is the angle required. Prob. 13. Through point F draw a straight line which "would meet the intersection of A B and C D if continued. Draw F i and F 2 at any angle. Connect 1-2. From point 3 anywhere on A B make 3-4 parallel with 1-2, 3 E parallel with i F, and 4 E parallel with 2 F. Pass a straight line through points F and E, which will be the desired line. Prob. 14. Find the mean proportion between the two lines A B and C D. Lay off on E F, 1-2 equal to A B and 2-3 equal to C D. Bisect 1-3 in 4. With 4 as center and radius 4-1, describe a semicircle. From 2 erect a perpendicular (Prob. 9) to E F, cutting semicircle in 5. 2-5 will be the desired mean. Prob. 15. On the given line A B to construct a square. Draw B i perpendicular to A B (Prob. 9) and equal to A B. With points A and i as centers and A B as radius, describe arcs cutting in 2. Draw A-2 and 2-1. Prob. 16. On a given line A B to construct an equilateral triangle. With A and B as centers, and A B as radius, describe arcs cutting in i. Draw A i and B i. Prob. 17. Having given the three sides of a triangle, as A B, C D and E F, to construct the figure. With point B as center and the radius C D, Plate 2. PBOB. 10. I * \i PROB. II. PROB. 12. PROB. 15. PROB. 14. PROS. 16. xl * / \ 1 ' \ \ \ / \ / \ / / \ ,1 L 4 i IS . c PROB. 18. '2 1 = ^ 1" / i3 STRUCTURAL DRAWING. describe an arc. With point A as center and E F as radius, describe an arc cutting the first in i. Draw A i and B i. Prob. J8. On a given base A B to construct a regular hexagon. With A and B as centers and A B as radius, describe arcs cutting in i. With i as center and the same radius, describe a circle. A B is equal to ^ of its circumference. Step off points 2, 3, 4 and 5, and draw B-2, 2-3, 3-4, 4-5 and 5-A. Prob. J9. Within a given square A B C D to inscribe an octagon. Draw the diagonals A C and B D, intersect- ing in i. With A, B, C and D as centers and radius A i, describe arcs 2-3, 4-5, 6-7 and 8-9 : draw 3-6, 5-8, 7-2 and 9-4. Prob. 20. On a given line A B to construct a pentagon. With A and B as centers and radius A B, describe arcs cutting in i and 2. Connect i and 2. With i as center and the same radius. describe an arc cutting at 3, 4 and 5. Pass a line through 3-4 to 6, and one through 5-4 to 7. With 7 and 6 as centers and radius A B, describe arcs intersecting in 8. Draw A 7, 7-8, 8-6 and 6B. Prob. 2J. On a given base A B to construct an octagon. Erect perpendiculars at A and B. Bisect the exterior angles and set off A i and B 2 equal to A B. Connect 1-2, cutting the perpendicu- lars in 3 and 4. Make 3-5 and 4-6 equal to 3-4. Extend line through 5-6 indefinitely. Make 5-7, 6-8, 5-9 and 6-10 equal to 3 A. Draw A i, 1-7, 7-9, 9-10, 10-8, 8-2 and 2 B. Prob. 22. Within a given equilateral triangle ABC to inscribe a circle- Bisect the angles of the triangle by Prob. 3. The bisectors will intersect in i. The perpen- dicular distance from i to any side of the tri- angle will be the radius of the desired circle. Note, this problem is true in any form of tri- angle. Plate 3. PROS. 13. P. ? C X Ir-// V\ PROB. 21. PROS. 22. PROB. 23. 0. _?_ c PROB. A iz 20 STRUCTURAL DRAWING. Prob. 23. Within a square A B C D to inscribe four semicircles, each touching; one side of the square and their diameters forming; a square. Draw diagonals A C and D B, intersecting in i. Draw diameters passing through i. Draw 2-3, 3-4, 4-5 and 5-2. Draw 6-7, 7-8, 8-9 and 9-6, which give us points 1 1, 12, 13 and 14, the centers of the required semicircles. Prob. 24. Within a given equilateral triangle ABC to inscribe three equal circles, each touching; two sides of the triangle and two other circles. Bisect the angles of the triangle, letting the bisectors cut the sides of the triangle in i, 2 and 3. With centers i, 2 and 3 and radius 1-2, describe arcs cutting bisectors in 4, 5 and 6, the centers of the required circles. A perpendicu- lar (Prob. 8) from the center of any circle to the side of the triangle will determine the radius of the circle, and also the point of tangency. Prob. 25. Within a given circle to inscribe three semi- circles, each touching; the circumscribing; circle, and their diameters forming a regular triangle. Draw two diameters, 1-2 and 3-4 at right an- gles to each other, intersecting in 5. Divide the circle into twice as many parts as there are semicircles to be inscribed, beginning at i. Draw diameters 6-7 and 8-9. Connect 2-3, cut- ting diameter 8-9 in 10, which locates one point of the required triangle. With 5 as center and radius 5-10, set off u and 12, which when con- nected form the triangle. Draw 10-11, 11-12 and 12-10, giving points 13, 14 and 15, the cen- ters of the required semicircles. Prob. 26. Within a given square A B C D to inscribe four equal circles, each tangent to two others and two sides of a square. Draw the diagonals and the diameters inter- secting in i and giving points 2, 3, 4 and 5. Connect points 2-3, 3-4, 4-5 and 5-2, intersect- ing diagonals in 6, 7, 8 and 9, which will be the centers of the required circles. Prob. 27. Within a given circle to inscribe any num- ber of equal circles which shall be tangent to two others and to the circumscribing circle. In this problem, five. Divide the circumference of the circle into twice as many equal parts as there are to be circles inscribed. Produce the diameters on STRUCTURAL DRAWING. 21 either side of 2-7 until they meet a perpendicu- lar erected to 2-7 at 2. Bisect angles 12 and 13 and let bisectors cut diameter 2-7 in 14. With i as center and radius 1-14, draw a circle cut- ting diameters in 15, 16, 17 and 18, the centers of the required circles. Prob. 28. To draw a line tangent to a given circle through a given point A. Pass a line through center i and point A in- definitely. With point A as center and any ra- dius, cut this line in points 2 and 3. With 2 and 3 as centers and any radius, describe arcs cutting in 4 and 5. Connect 4 and 5, which will be the desired line. Prob. 29. To draw a line tangent to a given point A in a circle when the center is not accessible. Draw any chord A i. Bisect the chord and arc (Probs. i and 2) in 2 and 3. With A as center and A 3 as a radius, draw an arc 4-5 ; with 3 as center and 3-5 as a radius, draw an arc cutting 4-5 in 4. Draw line through A 4 tan- gent to the circle. Prob. 30. Draw a circle tangent to a given point C in line A B and through the fixed point D without the line. At point C erect a perpendicular (Prob. 9). Connect C D and draw a perpendicular to its center (Prob. i) intersecting the first perpendicu- lar in i, which is the center of the required circle. Prob. 31. Draw a circle tangent to a given circle A, also to a given line B C at a given point D in the line. Pass a line through D perpendicular to B C. Lay off D i the length of the radius of circle A and draw A i. Draw perpendicular to A i (Prob. i) intersecting the line i D in 2, which is the center of the required circle. 3 and D are the points of tangency. Prob. 32. At a given point E in line D B draw two arcs of circles tangent at this point and to the two lines A B and C D. Make B i equal to B E. Make D 2 equal to D E. Draw E 3 perpendicular to D B, 1-4 perpendicular to A B and 2-3 perpendicular to C D. Points 3 and 4 are the centers of the required arcs. STRUCTURAL DRAWING. Prob. 33. Having given parallel lines A B and C D, to connect by two arcs of circle which shall be tangent at points B and C and pass through point E, which is any- where on line B C. At B and C erect perpendiculars. Bisect B E and E C, intersecting the perpendiculars in i and 2, the centers of the required arcs. Prob. 34. To draw an ellipse by means of a trammel, having the axes given. The semi-diameters of the ellipse are repre- sented by A B and A C. Lay off on the straight edge of a piece of paper 1-2 equal to A B, also 3-2 equal to A C. Keeping point i on the short diameter and point 3 on the long, mark off as many points at 2 as desired to form the curve of the ellipse. Prob. 35. To draw a line tangent to an ellipse at any given point, as E, in the curve. With point C as center and A i as radius, describe an arc cutting diameter A B in F and F', which points are called foci. Extend a line from F' through E indefinitely. Make E 2 equal to E F. Bisect the angle F E 2, giving the desired tangent. Prob. 36. To draw a line tangent to an ellipse, passing through a given point E without it. Find the foci as in Prob. 35. With point E as center and radius E F, describe an arc. With F' as center and A B as radius, describe an arc cutting the first arc in points i and 2. Connect F' i and F' 2, cutting the ellipse in points 3 and 4. Draw lines from E through 3 and 4, which will be tangent at 3 and 4. Plate 4. PROB. 28. PROB. 29. PHOB.50. PROB. 31 PROB. 32. -*- ,0 PROB. 53. CHAPTER III. SIMPLE PROJECTION, INTRODUCING THE PRINCIPLES OF WORKING DRAWINGS. THE working drawings of any object are such drawings, accompanied by the proper measure- ments, as will tell all the facts concerning that object. Such drawings if sent to a mechanic would be sufficient to enable him to perform the desired piece of work without further ex- planation. The number of views required de- pends entirely upon the character of the subject to be drawn; for instance, in Plate 5, Fig. i, two views are sufficient to tell all that concerns the cube, whereas for a more complicated object three or even more views may be necessary to tell all the facts. Plate 5, To draw the front and top views of the cube in three positions. Fig. i represents the cube so placed in the top view that two edges are parallel to an imag- inary horizontal line. In drawing the front view we suppose the cube to be resting upon a horizontal plane upon one of its faces, and so placed as to appear as a square if seen directly in front. In the top view we are supposed to be looking down upon the cube, its position being unchanged. As noted before, the cube will be seen as a square in both the front and top views, and these should appear directly above one another. The space between the two views is immaterial, but should be such as to appear well on the sheet. The horizontal lines should be drawn with a T-square, having its head against the left-hand edge of the board, whereas the vertical lines should be drawn with a triangle resting on the edge of the T-square blade. Only three measurements are necessary. They should be carefully placed as indicated in the drawings, the arrow heads just touching the Plate 5. FIG. I. FIG. 5. FRONT VIEW FRONT VIEW FRONT VIEW 26 STRUCTURAL DRAWING. extension lines from those that they measure, not overrunning or falling short. Fig. 2 represents the cube turned in the top view so that its edges make angles of 45 with an imaginary horizontal line. Fig. 3 represents the cube turned in a similar manner, but at angles of 30 and 60 with a horizontal line. In both of these figures the top views should be drawn first. From them project down and construct the front views di- rectly opposite the front view in Fig. i. These problems should be lined-in with a medium grade pencil, making the result lines, or, in other words, the outlines" of the cubes, strong and black, uniform in thickness throughout the drawing, and much resembling an inked line. Extension lines should be at right angles to the lines to be measured, and measurement lines should be left light. Care should be given to printing and figuring, as the appearance of the sheet depends much upon this feature of the work. Figs. 2 and 3 are not necessary as work- ing drawings of a cube, but are given as simple exercises for the use of the T-square and trian- gles, and as a method of representing foreshort- ened surfaces and of placing measurements upon inclined lines. Plate 6. Fig. i represents the front, top and side views of an equilateral triangular prism placed so that two of its faces are equally visi- ble in the front view. In this drawing the top view should first be made, from which the front and side views are projected. The stu- dent should take notice that the width of the side view is equal to the altitude of the trian- gles formed by the top view and not to one of its sides, as many beginners are apt to suppose. Fig. 2. Draw the front and top views of a regular hexagonal prism according to the meas- urements given. In this, as in Fig. i, the top view should be drawn first and the front view projected directly below. Both the triangle in Fig. i and the hexagon in Fig. 2 may be con- structed by the use of the 30 and 60 triangle, or more accurately, by the use of the compasses as given in geometric problems 16 and 18. Plate 6. FIG. I. FIG. 2.. TRIANGULAR AND HEXAGONAL PRISMS FRONT VIEW SIDE: VIEW FRONT VIEW 28 STRUCTURAL DRAWING. Pkte 7. The drawing at the left represents the front and top views of a square pyramid. Note that the height of the pyramid is given on a measurement line parallel to the axis and not parallel to the slant line of the pyramid. The chimney model is represented by front and top views and a vertical section ; this section is supposed to be cut through line A and the front half removed. The surface cut by this ver- tical plane is section lined at 45. Different pieces of material adjoining one another are sec- tion lined in different directions as shown in this problem. Plate 7. SQUARE PYRAMID AND CHIMNEY MODEL A 1 H ,- ii e" VI I I TOP VIEW I III II I I I I I I 'T i i i I FRONT VIEW SECTION FRONT VIEW STRUCTURAL DRAWING. Plate 8. The drawing at the left represents the front and top views of a paneled prism turned at an angle of 30 and 60. The top view should be drawn first ; the main lines of the prism and the vertical lines of the panel may then be projected down to their respective places as indicated by the connecting lines. In the drawing at the right we have the front and top views, and a vertical section of a hollow flanged cylinder. The top view should be drawn first, as in nearly all cases when the object is based upon the cylinder. As but one piece cf material is shown in the section, all the section lines run in the same direction. In mechanical drawing, the front view of objects based upon the cylinder are frequently represented half in elevation and half in section, instead of making a separate drawing of the section, as in this case. Plate 8. SQUARE PRISM AND HOLLOW CYLINDER *- -i"- TOP 1 VIEW 1 "7- ~ l TRONT VIEW SECTION FRONT VIEW 32 STRUCTURAL DRAWING. Plate 9. Draw the front, top, right and left the front view. The spaces A', B', C', D' and E' side views of a cylinder and a cube, as placed in of the right side view are equal to spaces A, B, the drawing. Locate the top view, from which C, Dand Eof the top view The vertical heights project points down, so placing the objects in in the side views are equal to those of the front. ('UNIVERSITY ' Plate 9. COMBINATION or CYLINDER A* CUBE: 4 1 TOl'' VIEW I I I I I I I I r >ICO .1 -EH SIDE VIEW. TRONT VIE1W. RI&MT SIDE VIEW. 34 STRUCTURAL DRAWING. Plate JO. Fig. i represents the front and top views of a hexagonal prism. In the front view this object shows two of its faces equally and is so inclined that its base makes an angle of 30 with the horizontal plane. First, draw the front view, making the short lines at 30 and the long lines at 60, and the distances A and B in the front view equivalent to A' and B' in the diagram Fig. 2 ; this diagram being a reg- ular hexagon. In the top view the distances C, D and E are equal to C', D' and E' in the diagram. Having obtained the position of these horizontal lines, project points in the front view to corresponding lines in the top view, giving points to be connected by straight lines. Fig. 3. The top view as shown in this figure is the same as in Fig. i, but turned at an angle of 45. The front view of this object in the turned position must be quite different in appearance from that in Fig. i ; but all its points will appear to be at the same height as before it was revolved. This being so, we have simply to project corresponding points in the top and front views until the lines intersect, giving the several points, which are connected by straight lines. For instance, point F may be traced from one view to another, as shown in the drawing. ERSITY of / Plate 10. no. i. FIG. 3. FRONT VCW FRONT VIEW 3 5 STRUCTURAL DRAWING. Plate H. In this plate we have the hexago- the hexagonal prism as shown on the left por- nal prism resting across the square prism, their tion of the plate, proceed as in Plate 10. projections to be- carried out precisely as in the Measurements should be placed only upon plate preceding. To find the projection of lines that are not foreshortened. Plate i i . HEXAGONAL AND SQUARE PRISMS FRONT VIEW FRONT VIEW CHAPTER IV. STRUCTURAL DETAILS. PLATES 12, 13 and 14 are given to acquaint the student with the exact shapes given to the principal members that enter into the steel structure. He should make careful drawings, full size, according to the given measurements, which are taken directly from the standards used by the leading rolling mills of America. The slant for the flange in both the I and channel beams is drawn to the American Stand- ard of one to six, or i6f per cent. Fillet A in both the I and channel beam is formed by an arc whose radius is ^ the thickness of the web at its thinnest section. Fillet B is formed by an arc whose radius is equal to the thickness of the web plus j^ of an inch. If the student cannot secure an engineer's scale, he may reduce the decimal fractions to the nearest sixteenth or thirty-second of an inch. With care the scale illustrated below can be made on a heavy paper. This will give any measurement necessary from ^ of an inch to six inches. OJ2.34.Sj67.8S 1 u i 997 >[ 1 Sr^ ^^ d Tl r^ ^ 8^ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ ,a^ \ \ \ \ S * ^^ ,#xyJ i * ^pHi "^. " .. " I 4X* I 4x4 L. fa 6x6 L. at- ANGLES W.TM UNEQUAL LEGS 3" ^zmmmsim ^mmmm^rn^ tt&k'L. ' ' 2 ''- 1 "- -2'- L. eV- vL^i_ V)i ill fa n( p^ , ^ D \ - Tf *D I T 'f? _i .L 50 STRUCTURAL DRAWING. Plate 20. This sheet represents the standard drawings, given by the American Bridge Co., of the loop rod, eye bar and clevis. Two views are given of both the loop rod and eye bar, and three of the clevis. This plate makes an excellent exercise in drawing especially in the use of the tangents. To derive the full benefit of the problem the student should make this drawing at least one half full size. STRUCTURAL DRAWING. Plate 21. This plate gives the working drawings of a sleeve nut and turnbuckle, accord- ing to the standard proportions given by the American Bridge Co. The student should first consider the center lines, and after they are placed block in the main proportions ; the small details will follow in order. This affords an excellent exercise in drawing, especially in the use of the tangents. Plate 2 i . L: SLEEVE NUT TURNBUCKLE 5CALE - 12 54 STRUCTURAL DRAWING. Plate 22. This plate presents four typical anchors that are in general use. In each draw- ing the front view and horizontal section are shown, that is, the I beam is supposed to be cut horizontally just above its connection with the anchor, thus showing the details more clearly. In Fig. i, A represents the front view of the I beam with its connections, B the top view or horizontal section. In drawing this the student should first consider the front and top views of the I beam, after which the anchor and its details may be added. K I Plate 22. B A .T F1G.1. ft -/,< 1 QD . I *-4 <-3^ iioKf f ANCHORS :r -H 1U < o <0 STRUCTURAL DRAWING. Plate 24. This plate gives the conventional signs for rivets as designed by F. C. Osborn, C. E. Fig. i represents the front and bottom views of two angles riveted to a web plate. The student will note that the four rivets at the left of the dotted line are designated as Shop; this means that the riveting is to be done at the shop ; those at the right of the dotted line are designated as Field; that is, the riveting is to be done at the building. The student will also notice that the signs indicate whether the rivets are to be countersunk or not, and the side on which the countersinking is to occur. Fig. 2 gives the method of showing whether the heads of the rivets are to be flattened or not, and how much ; the amount being indicated by the diagonal lines. Plate 24. OSBORN RIVET SIGNS SHOP PLAIN COUNTERSUNK N CHIPPE:D I FAR SIDE NEAR SIDE BOTH SIDES FIELD COUNTER SUNK *NO CHIPPED FAR S10F. NEAR SIDE BOTH SIDES PLAIN 1 . i a r 1 15 X ft k ^ ft x J 1 , , T ^ 9 * X 5 * V^ - y~~~}%t~~x ^> ' I rxvvxVx'XxN c V c A pz: i 1 1 V -i i JV/Ayy.'V^- *u^, i 1 1 %//, ^////^/.^ ^^ ^ FLATTEN CD TO i" HIGH FAR SIDE NEAR SIDE BOTH SIDE.S FtG-1- FLATTENED TO FAR SIDE NEAR SIDE BOTH SIDES FLATTENED FAR SIDE NEAR SIDE BOTH SIDES I 60 STRUCTURAL DRAWING. Plate 25. This plate represents the rivet differs a little from the preceding, being not signs used by the American Bridge Co. and quite as complete, known as the Pencoyd System. This method Of . CAi.irc*. in (N tL LJ H Z U D 9 o O co r o h Q LJ Z h I- CL o _J LJ L. ir y h z 8 o 62 STRUCTURAL DRAWING. Plate 26. Fig. i gives the front and top Fig. 2 represents the drawing of a double views of a single laced column. The student laced column. In this, as in Fig. i, the lacings will note that this is made up of two channel are drawn at an angle of 45. beams held in position by plates of steel, in Fig. 3 gives several standard sizes of lattice this instance 2" wide by \" thick. bars in general use. "fr )- * -< )- -< ?- : * 00 rj i| .1 -|F BssmnB|

;l i r> 1 > '*-* K/\M w * * ; T y 3 o |i| biJ!L^,_ji,^ H * * M i " W^ iTW- f J S OJ o .1 h u > E H*. M'-n ^ o- H u > i|! CC "lD|O -.jl-l G>- l fcs-S SFsl I7T E \rfS.\ /-t rO)^ N <_ _*. r-|co -.*2-J i 1 ;f 2 ^ j 1 0- I k _I IP 6 ^^ lu o C 6 4 STRUCTURAL DRAWING. Plate 27. This and the following plate rep- resent the framing angles that are in general use among the principal construction compa- nies. The student will note that in every in- stance, the measurement from the center of the first row of rivets to the back of the angle is two and one half inches, and from the center of the first row to that of the second, two and one quarter inches. This regularity is de- signed to simplify the punchings for the rivets, so that the several holes may be punched at one operation. o r STANDARD FRAMING ANGLES ~ f 3^-^i .? ttZl.^-^040' 7 X If ! j n 00 1 S / ,-or- *t i* j -M- i J < - IT * tSBL ^ 1 A i 1 A 1 r J O , a . I 1 * 1 i .it^ p 4 I 1 1 f 1 -.9 < ?2->* V k ** -s- KJf2> _ o -^ z _u ll*~ j -J|iwJ t ..fz^i*- i i -J | to -( < >l ~\ t < -( M > ) f i ( i t i -^ f ^ c ^ c ^ , T -!rj csl & 1 y k j < \ ) } c \ ) } J V. ^ /" j \. -\ c J ~\ ^ ^ ^ J ^ J 9H 'UNIVERSITY a en LJ J CD z z I n D: | f CO + I I t t T-f tr Tfc -.-. -c-i- JS l-o ^4-f -t-i- J_ :_L 68 STRUCTURAL DRAWING. Plate 29, This plate presents the front, top and side views of the framing of a steel floor beam into a girder. The isometric drawing in the upper right-hand section of the plate is given to show the student more clearly the relative positions of the different members, the positions of the rivets being omitted. The size of the rivets in this and all other plates to follow are to be f " unless otherwise mentioned. The drawing should be made at least one half full size, and all measurements placed as indi- cated. O* 'HE r U N I V^. ft 3 I T Y * Plate 29. ISOMETRIC VIEW 12' 9" 6" J" O SCALE = I i. I I I l4-l 7 o STRUCTURAL DRAWING. Plate 30. This plate represents the front, top and sectional views of a plate girder. This girder is built up with one central plate, known as the web, and reenforced by top and bottom plates and angles. The student will see that the angles used in the upper and lower members are 5" x 6" while the stiffeners or upright angles are 4" x 4". Both single and double riveting is used in this girder. The space between the rivets which is technically called " pitch," is governed by the character of the design and the load to be carried. The maximum spacing for a f " rivet is 6" and the min- imum 2\". The distance between the center of a rivet and the outside edge of any flange should not be less than ij". The measurement directly to the right of the section is read thus : Six 3^" spaces are equal to i '-9". This applies to the spacing of rivets when several are spaced equally as in this drawing. This problem should be drawn at least one fourth full size. Plate 30. 1 f be. &, f &{ \ f \ c > lid *\ ( k_L ^ "V -f 'J| ) \ \ \ 2 r \ r -\ f \ c \ c \ c &f >|! c ~\ f ~\ f 51 \ c Be S f -' )|!c 1 * P 'J C p i]q DETAIL or PLATE GIRDER 2jf 3 j- 3 - - 3-, I-COV PL Ifc'xjf S ^ A "\ / J 4 r j-J \ jA. / \ /" -^ f N /" ^ / ^ ^ ^ /Y\ f >, f 1 I y > T -^ V, A f ^ ^ V. rh y \. ; 1 ^ I ^ \- J V, J c j A I r &_/" i rh c c r 9 ^ ^ V- ^ ^ c s ^ r ") C ^ / Br ^ _/ ~\ 4 T "I C =L-~ - > < >- Z-L? 3X6X5 -< J- j -( > -i H 'too -( >- -i+ : 5 I-WB 30X|- -( V -i >- -X.x -< > t * .X >0 -t #- -i >- ^IC -< )- -< >- - > 2-L 5X6 X|" -< )- c &(- Df ^ c K / ""i r" s / *\ f] -, r ~^ f \ T 4, C 1 rfi cb f (Jo- ^ \ ^ N S 9 ^ < ^ \ / s /- -, f ^ ^ J //////////////////////////////////^t: - V v ^ 'Uy v I-COV -j- - -- \/ ^ / ^ / \_ PL I6X|" ^ S \ X \, /\Le ) \, 1 1 1 7 1 - r a to -i I ) . 5 M > ) i c -c -c c c > > > ) "> tp ^ l^J ^ -> -< ( ( ( < f ) ) ) ) ) a-i5 0^x6 L,^ loko 2-WB5 v SHJ Al tl_ 30x2" 6 e'x J -( < c ( ( > ) ) ) ) >- -( >- -< )- -( )- -< >- -< p- 1 b_ 1 & p- 1 i c ^ d^ rh rl *- rh 3< > < > < )- ( f ) :)- -C >- -< tr h 1 1 c < ) r\i I _ * SiZ _/S C|; ^ cp cp vU S g W/tt/^W^///////// 'i I-COV. PL. J6X 5." 8 Mill l<0 MM F r 1 STRUCTURAL DRAWING. Plate 32. This drawing presents the front, top and side views of a base together with the connection of a "closed column." The base is made of cast iron, the top surface being faced or planed off at the mill, giving an even bear- ing surface for the column. The small circle at A represents a hole in the casting, about i" in diameter. These holes are arranged so the mason can pour in grout (thin mortar), after the ba: e is properly set. By this method the mason is able to fill any openings that may have been left unfilled. This type of base is quite generally used ; but in practice, special designs and dimensions must be considered to meet the requirements of the particular problem. Plate 32. DETAIL or BASE: FOR COLUMN FACED 1 L ^ 7 6 STRUCTURAL DRAWING. Plate 33. This drawing gives the front, top and side views of a "closed column," built up of plates and angles. It is an enlarged detail of the preceding plate, taking in the portion of the column above the face line. Detail A gives the measurements necessary to make the drawing of the upright angle, while section B gives the measurements for the horizontal angle. /--\ s\ r t- _~\ * r v ^N c^ r\ c.~\ ci L^^_ u _i < o 7 8 STRUCTURAL DRAWING. Plate 34, This drawing presents an " open section column," built up with an I beam and two channels. Detail A gives a portion of the necessary measurements in making the drawing. The student should draw this to a large scale in order to get the full benefit of the problem. a Kt 1 ; J, J, -4; 4= y ^P A A T V7| =tz.di^. >_:i^:_< ll U -I < O <0 8o STRUCTURAL DRAWING. Plate 35. This plate presents a " closed col- umn," built up of four Z-bars and three plates. Two angles are used at the base to stiffen and create a proper connection between the base and the column. Fig. i gives an enlarged de- tail of a portion of one of the Z-bars. This is given to assist the student with the minor details. OF THE E 01 o>- >J. "" II UJ _l < O <0 82 STRUCTURAL DRAWING. Plate 36. This plate gives the front, top and side views of the connection between an I-beam and a Z-bar column. This is one of the sim- plest connections in use, the supporting mem- ber being simply an angle iron. The student will note that the solid black openings as at A indicate "field riveting," that is, the riveting is to be done as the building is being erected. Fig. i presents an enlarged detail of one of the Z-bars while Fig. 2 gives the detail of an I-beam. U z 2 1 3 7 i o o s K 5 U rrS Z 012 IO O ,OI2'( ET"f _1- 1*- ^ *H t O C rt 1 ;. rj sw( ,fn(-^ v ^ w ^ 7 lO | t - > #- ^ - c "N f ^ \ J k i \ - J k ? J > 1. rh rh rf^i -C. V^ "Vn a Vfl ^-f^ X- "jJ-U II u J < o to 86 STRUCTURAL DRAWING. Plate 38. This plate gives the front, top and side views of a channel column with its various I-beam connections. In many respects the connections in this are similar to the last plate. Just above the I-beam connections a method of splicing the column is shown which usually occurs every second story. Fig. i gives the detail of the channel, Fig. 2 the detail of the 12" I-beam, and Fig. 3 the detail of the 8" I-beam. S * t +1|'- ^M> STRUCTURAL DRAWING. Plate 39. This plate gives a typical form of the Phoenix segmental column. The col- umn is seldom used on account of expense, but makes an excellent exercise in drawing. < U o CO z o (J u. *- o U O u z LJ O TTA M H SLEEPER I J | i~ i t I Tj ~B IS* |I BEAM c.lRDtJ. 1 1 LJ 1 -/ I SLEEPER i IT / 1 i DETAIL OF FLOOR CONSTRUCTION ISOMETRIC VIEW or TERRA COTTA BLOCK i" j ! 6 >K l-b -*i / J \ TERRA toTfA ARCH/ .r \ aJ JL | i aa aa aa aa aa aa ac ac . :tj . j'ji sKP * 1-0 > MB -(tiitj x^_ p .ASTER a' 3CAUE 102 STRUCTURAL DRAWING. Plate 46. This drawing gives the front, top and right side views of the plate and angle col- umn used in Plate 44. In making the drawing the student will do well to locate the main lines of the column and girder in all three views be- fore considering the minor details. Fig. i gives the detail of the angle used in building up the column. Fig. 2 gives the de- tail of the 15" I-beam girder. Fig. 3 gives the detail of the 9" I-beam. Fig. 4 gives an iso- metric view showing the relative positions of the several members. Make the drawing to as large a scale as possible. 104 STRUCTURAL DRAWING. Pkte 47. This plate represents the working drawings of column, No. 32, Plate 44, showing the connections between the spandrel beams and the column. These beams are located at the floor level and carry the wall above as well as their portion of the floor. Figs, i, 2 and 3 represent the front, top and side views of the spandrel girder as shown at section E. F., Plate 44. The student should first lay out the three views of the cplumn and the main 15" girder, after which proceed to the details. Plate 47. FIG 3 FIG 1 9~ 12 1 1 "V *1 i u ~ 1 ..i- >; 1 A" 2,-r-j/ "\//. 22 X/////A i '//// 00 Plate 4Q. COLUMN CONNECTION, WALL AND FLOOR CONSTRUCTION CHAPTER V. STEEL MILL CONSTRUCTION. Plate 50. THIS plate gives the elevation and two sectional views of a typical mill construc- tion. The corrugated iron in the elevation is largely omitted to show the student the method of framing. In drawing this, it will be well to make the sections first and project directly from these to the elevation. The drawing should be made large ; and for a more definite idea of the construction the student will do well to con- sult the four plates of details that follow. o m g J3 Q. 2 O (J < O fl 61 Pi a "?* 4 no STRUCTURAL DRAWING. Pkte 51. This plate presents the detail drawing of a corner of the building, including a part of the foundation. While making this the student should consult the previous plate, and not merely copy the lines as given. Every line should be considered in both drawings. The corrugated iron in the top view is shown as a single wavy line. It is best to draw the sections before the elevation. 'UNIVERSITY V /->r HVJO ^i^yoNoo CD STRUCTURAL DRAWING. Pkte 52. This plate gives the detail draw- ings of an upper corner of the building, taking in the cornice. The section at the right should be considered before drawing the elevation. Draw the main outlines of the frame before any of the minor details. Note that the front view of the gutter is omitted, leaving the framework to stand out clearly. =| Id Q i i ;, _ _ > i S y 'P 1 i t \ Q_ i *) ~ 1 > si h T33J.S V ~^~ I J 1 L-t j CO in s a. n6 STRUCTURAL DRAWING. Plate. 54. This illustration represents the detail of the window and a portion of the foun- dation, as shown in Plate 50. This and the above mentioned plate should be studied care- fully. Draw the two sections first, and then project to the front view, completing the draw- ing. o Q z U Q r-.* c H |_, K-jfc- n 1 3u i 3-0+ 8 n8 STRUCTURAL DRAWING. Plate 55. This plate presents the details of In making the drawing consider first the see- the window, as shown in Plate 50. This draw- tions and the main framework, and later the ing takes in the upper portion of the window as minor details, well as a section through the meeting-rail. Plate 55. DETAILS OF WINDOW ID in I22 STRUCTURAL DRAWING. Plate 57. This illustration gives the general ing consider the plates that follow, especially in outlay of a sixty-foot truss, showing the position locating the smaller details, of its several members. In making this draw- Plate 57. DETAIL or TRUSS 124 STRUCTURAL DRAWING. Plate 58. This and the three following plates represent details taken at the principal connec- tions, as shown in Plate 57. In this as in the details mentioned several views are given to bring out all the facts con- cerning the connections. The student should make a careful study of every portion, noting the manner in which the members are connected. Plate 58. DETAILS OF TRUSS Plate 59. DETAILS or TRUSS i I i 1 O (~\ f~} ~~ 1 s A ,r, c ~^ffr iJ rK ffi ^ q t\j -> ^ [^ 7^ -*VJ" y\ '~? fi (i (H V) y * i SECT ION C-D SECTION o-A- DETAILS OF TRUSS Plate 60. ( . ^ Xjijiw: \ /" AJ^ s ]L ~M 4- -^Jrvfrr 7~T T i f J ^ Plate 61, DETAILS OF TRUSS CHAPTER VI. IRON STAIRCASE CONSTRUCTION. Plate 62. This plate gives the front, top and side views of an iron staircase. In making a drawing of this the student should study the three following sheets of details and not merely copy the lines given. The exercise can be made more helpful by changing the conditions of the problem slightly, and using this as a reference plate. OF THE fuNlVERSlTYj OF Plate 62. DRAWING 5TAIRCA5E 134 STRUCTURAL DRAWING. Plate 63. This plate presents the detail draw- ing of the lower portion of the staircase together with the newel-post, as shown in Plate 62. The isometric drawing in the upper left-hand portion of the sheet is given to assist the student, showing how the riser and treads are secured to the newel-post and the stringer. The student in making this drawing should first locate the risers and treads in all three views, then the newel-posts, and finally the minor details. late 03. 136 STRUCTURAL DRAWING. Plate 64. This drawing gives the detail of staircase taken at the square landing, Plate 62, showing the connections of the risers and treads with the angle-posts - and the stringers. The isometric drawings are given to assist in locating the various members of the staircase and show- ing their connections. To make an intelligent drawing this problem should be studied in connection with the above mentioned plate. Plate 64. NOTE-SLATE ON TWEAOS SLATt ON LANDING 2THICK 1 DETAIL OF ANGLE POST ISOMETRIC OT POST SHOWING ARRANGEMENT Of LUGS STRUCTURAL DRAWING. Plate 65. This plate presents the upper sec- connections between the stringer and the I-beam tion of the staircase (Plate 62), showing the girder. I -^ 'ETAIL 1 1 - I 1 4 J "ws" 1-6'- ,a -ijj . T- CM T Plate 65. 140 STRUCTURAL DRAWING. Plate 66. This drawing presents three views of an iron staircase which is enclosed on three sides by a brick wall. The student should first consider the plan, after which carefully lay out the outline of the treads and risers in both the front and side views. The following plates should be carefully studied in relation to the minor details. I 4 2 STRUCTURAL DRAWING. Plate 67. This plate presents the working drawing of the lower section of the staircase, including a portion of the newel-post. By the isometric drawing one will readily see the con- nections of the various parts. The details should be drawn as large as possible. The iron dowel protruding from the lug on the stringer, as rep- resented at A, is arranged to hold the slate tread in position. "V! .4,VE8.TV: Plate 67. DETAIL or STAIR 144 STRUCTURAL DRAWING. Plate 68, In this drawing we have the front, top and side views of an angle-post, showing how the risers and treads are connected with the stringers and angle-post. In making the draw- ing the student should first locate the angle-post in the three views, then the risers and treads, finally the lug connections. If he follows this method little difficulty will be encountered. 146 STRUCTURAL DRAWING. Plate 69. This drawing gives the connection main lines of the stringer and tread, finally the between the upper portion of the staircase and small details. The isometric drawing in the the floor construction. First locate the I-beam, upper left-hand section of the plate will greatly then the floor and ceiling lines, after which the assist the student. Plate 69. STAIR DETAILS i ~-*j T ttt-- CvW-S S'XE" FLAT BAR IMBED &W ED IN 148 STRUCTURAL DRAWING. Plate 70. This and the following four plates present an iron staircase in which winders are introduced. The main features in this problem are not unlike those of the two foregoing exam- ples, and by carefully studying the isometric drawings little or no difficulty will be encoun- tered. OF THE UNIVERSITY OF & OF * VUVE* S ' TY J M 1^ _o> J2 CL Plate 74. STAIRCASE DETAIL THIS BOOK IS DUE ON THE LAST DATE STAMPED BELOW AN INITIAL FINE OP 25 CENTS WILL BE ASSESSED FOR FAILURE TO RETURN THIS BOOK ON THE DATE DUE. THE PENALTY WILL INCREASE TO SO CENTS ON THE FOURTH DAY AND TO $1.OO ON THE SEVENTH DAY OVERDUE. JAN 1ft 1035 12 30 194? LD >. -t IAN. 11 194: 28 VD 04214