Page:Popular Science Monthly Volume 92.djvu/156

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��Popular Science Monthly

��When the intersections of these lines have been marked with a cross, connect the lines with straight lines and the pattern will be complete. Make allowances for seams and laps.

To develop the pattern for the large

���In the working out of this problem two additional steps are taken

pipe proceed in the same manner as de- scribed in the last article. First draw the lines G — H and K — L, obtaining the correct length by transferring the dis- tances from the points on the end view as was done in the problems in the pre- vious article; then run the lines up from the joint on the front view. Where the same numbered lines intersect, make a cross.

Now we come to the first new step required by this problem. No diiiiculty will be found with the lines 3 and 4, as it will be seen from the end view that lines 4 and 2 of the small pipe rest on them, but when you come up with lines 3 and 1 from the front view you will find that you have no place for them. By looking at the end view of the large pipe it will be noticed that lines 1 and 3 of the small pipe meet the large pipe exactly midway between 3 and 4 on the pattern. The point where the lines 1 and 3 from the front view cross this line marks the loca- tion you are trying to find, as shown in the drawing.

The second problem. Fig. 2, is worked out in a similar manner, but is made a little more complicated by the fact that it requires more extra lines to locate the pattern for the hole in the large pipe.

��Briefly, the steps to be taken are: Draw front view A, end view B; complete the front view A by drawing the joint. Do this in the manner described in Fig. 1, this being one of the two new steps men- tioned in the first paragraph; develop the pattern for the small pipe, in the manner already described, drawing the base line E — i and obtaining the correct length by transferring the distance from the bottom view; run the lines upward from the base line, and the lines over from the joint line, and where the same numbered lines inter- sect make a cross to indicate the pattern line.

To develop the pattern for the large pipe, draw the line G — H and K — L, obtaining the correct length by trans- ferring the spaces from the end view.

Now we come to another of the new steps in these problems. By looking at the end view you will notice that the hole in the large pipe will be between numbers 4 and 6, and that the hole does not rest exactly on the numbers. We also see that number 7 of the small pipe coming up from the bottom view meets the large pipe a short distance away from number 6. With the dividers, measure that distance and transfer it to the pattern as indicated by lines 6 and 7

���A little different application of one of the new stepS is shown in this problem

on the pattern. Lines 8 and 6 with 2 and 4 are a short distance away from 5 of the large pipe. Mark the distance on the pattern and number the lines with the same numbers as the spaces on the small pipe. Then from the front view

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