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pipe tee-joint, set at an angle of 45 cleg., as 

 shown in Fig. 2. The method is exactly the 

 same as for Fig. 1. Draw the front view A 

 (to get the correct angle follow the method 

 given in the last part of this article on easy 

 method of laying out angle). Draw and 



Popular Science Monthly 



This pattern for a round pipe is developed 

 in the same manner as for the other types 



number the bottom view C. Lay off the 

 base line D-E and project lines over for the 

 pattern. For the pattern of the horizontal 

 pipe, project the length upward and get the 

 length of the line H-K by stepping off the 

 distances from the end view F. To get the 

 hole G, run the points over from the end 

 view F on the front view A , then upward 

 until they cross the same numbered lines 

 coming from the line H-K. 



The method of developing the patterns 

 for the round pipe angle of 90 deg., shown 

 in Fig. 3, is exactly the same as in the square 

 pipe Fig. 1. A larger number of lines must 

 be used in this round pipe than in the 

 square pipe and the method, though the 

 same, may appear more complicated. 

 Draw the front view A and bottom view C. 

 Divide the bottom into 16 parts. Lay off 

 the base line D-E, and step off 16 spaces 

 equal to the spaces on the bottom view. 

 This will give the correct length of the base 

 line. Project lines upwards from the bot- 

 tom view until they strike the joint lines, 

 then project them over to the right until 

 they cross the same numbered lines coming 

 up from the base line D-E. Connect these 

 crossing points with a curved line and you 

 will have the pattern as shown in the 

 drawing. 



To develop the pattern for the horizontal 

 pipe, draw the end view B and divide it 

 into 16 parts. Lay off the line H-K the 

 correct length by stepping off sixteen spaces 



from the end view; then draw lines across 

 from these points. From the end view run 

 points 13 and 5 (which are shown as one 

 line on the drawing) over to the front view 

 until they strike the lines 13 and 5 coming 

 up from the bottom view C. Run them up 

 to the pattern until they cross lines 13 and 5 

 on the pattern. Do the same with the 

 other points. The dotted lines show the 

 half hole on the edge as explained for the 

 drawing Fig. 1. The pattern for round 

 pipe tee-joint having an angle of 45 deg., 

 shown in Fig. 4, is developed in the same 

 way as for the other three joints. 



Allowances for lock seams should be 

 made on all these patterns as explained in a 

 previous article. 



Easy Method of Laying Out Angles 

 for Tee- Joints 



Angles are sometimes laid out by means 

 of an instrument called a protractor, but an 

 easy method is shown in the illustration. 

 A circle, Fig. 5, contains 360 deg.; a half 

 circle contains 180 deg., and a quarter- 

 circle gives an angle of 90 deg. In the 

 circle, Fig. 6, is shown a quarter-circle 

 divided in half, which gives two angles of 

 45 deg. each; the other quarter-circle is 

 divided into three equal parts, which gives 

 three angles of 30 deg. each. If all of the 

 degrees in the various angles are added to- 

 gether they will total 360 degrees. 



Fiq.4- 

 Rotind 4-5 



r Seam 



The plan of development of a pattern for 

 a round pipe is the same as for the square 



In the circle, Fig. 7, one quarter of it is 

 divided into three equal parts of 30 deg. 

 each, one of which is divided into two equal 

 parts of 15 deg. each, and the other into 

 three equal parts of 10 deg. each. The 

 other quarter-circle is divided into three 



