## A Textbook on Sheet-metal Pattern Drafting, Volume 2 |

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axis base line circle completed cone construction Construction.—Draw convenient number corresponding cube cutting plane cylinder defined desired determined develop the patterns dimensions distance divided draftsman DRAWING PLATE elbow elements eleva ellipse equal spaces Explanation.—The figure flange foot front elevation frustum full view Gauge Number given horizontal line hypotenuse illustration inches in diameter indefinite length indicated irregular laid line A B line drawn line of intersection lines of sight lower base manner shown method miter line necessary number of equal object oblique octagonal octagonal prism parallel lines perpendicular pipe plan and elevation plate points thus located portion position preceding problem primary projectors principles prism produced projection drawing projectors drawn pyramid represented right angles rightly inclined scale scratch awl seam seen semicircle shown in Fig side elevation similar solid standard gauge stretchout student taken thickness tion transition piece triangles true length upper base usual vertex weight width

### Popular passages

Page 40 - To find the capacity multiply the inside length by the inside breadth and by the inside height and divide by 231, the number of cubic inches in a gallon, the result will be the capacity in gallons of the tank or vat. For example, a rectangular tank is 120 inches long, 108 inches wide, and 100 inches deep. What is its capacity?

Page 71 - C y of the outer circle. Before this blank can be utilized in the construction of a conveyor, it must be stretched, or " raised," by dies or by hand methods known to every sheet-metal worker. A method of development that more closely approximates the theoretical standpoint, but one that is seldom used in practice on account of the waste of stock involved, is shown in Fig. 40. By this method it is first necessary to construct an additional helix that will follow the central line of the helicoidal...

Page 66 - FIG. 38. conveyor flight is referred to by mathematicians as helicoidal, and as will be seen from the drawings now to be made, is such as would be developed by a straight line that is at all times held perpendicular to the axis of the cylinder, but yet is constantly moving upwards along the line of the helix. Further explanation of the principles involved will be given during the construction of the drawings. For the purposes of this problem, it may be assumed that the conveyor tube is 12 inches...

Page 116 - Through a sphere whose diameter is 10 in. a cylindrical hole of 5 m. diameter is bored. Find the volume of the solid if the axis of the cylinder passes through the center of the sphere. Ex. 1251. The surface of a sphere is equivalent to the lateral surface of the circumscribed cylinder. Ex. 1252. Two bi.rectangular spherical triangles are equal if the oblique angles are equal. Ex. 1253. Find the ratio of a sphere to its circumscribed cube. Ex. 1254. The area of a zone on a sphere...

Page 43 - The capital has two rows of leaves, eight in each row, so disposed that of the taller ones, composing the upper row, one comes in the middle, beneath each face of the abacus, and the lower leaves alternate with the upper ones, coming between the stems of the latter; so that in the first or lower tier of leaves there is in the middle of each face, a space between two leaves occupied by the stem of the central leaf above them. Over these two rows is a third series of eight leaves, turned so as to support...

Page 25 - ... determined, the triangles may be constructed as shown at Fig. 1 (c). Draw the line ab, making it equal in length to the corresponding line in the elevation — that is, a' b; next, describe an arc from a as a center, with a radius ac, taken from the plan at (a); intersect this arc by an arc described from b as a center, with a radius equal to the length of the hypotenuse of the triangle whose base is b' c

Page 91 - N and space off on its length the widths ab, bc, cd, etc., as taken from the outline of the section; draw edge lines and developers and trace the curved outline of the pattern as shown in Fig. 44. As previously stated, the scoop shown in Fig. 43 is made up of parts that are considered as irregular conic frustums. This being the case, the projections may be made to better advantage if the cones are first represented in their full outline, as in Fig. 45, and the frustums afterwards designated by suitable...

Page 3 - Fig. 2 (a), an angle a be is constructed whose measurement will be the same as that of the desired elbow — in this case 90°. From b as a center and with any convenient radius, describe an arc, as shown, that shall intersect ab and bc ; bisect the angle abc by the line bd and then divide that portion of the arc included between the lines...

Page 16 - On the contrary, it represents an outlay of six dollars; he is used to it; he measures everything by it; and he is mad when anything does not measure to suit it. A still more serious difficulty arises from a very common mode of ordering. We frequently have orders for such a gauge, 'light' or 'tight,' 'full' or 'scant,' 'heavy' or 'easy'; or such a number and one-half, for instance, 15£.

Page 14 - No trade stupidity is more thoroughly senseless than the adherence to the various Birmingham, Lancashire, etc. gauges, instead of at once denoting the thickness and diameter of sheets, wire, etc. by the parts of an inch, as has long been suggested * * * * To avoid mistakes that are very apt to occur from the number of gauges in use and from the absurd practice of applying the same gauge number to different thicknesses of different metals in different towns, it is best to ignore them all, and, in...