Simple Designs for Sheet Metal Working 



VI. — Method of developing patterns for elbows of various shapes 

 By Arthur F. Payne 



Director of Vocational Education 



T 



O the students who have been follow- 

 ing and working out the problems 

 in this series of articles, the six 

 elbows drawn and described will be simple 

 to develop. The first three — the square, 

 oblong and oval elbows — are in common 



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6 



'," — Pattern 



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everyday use. The others are 

 more uncommon, and are used 

 in special cases for special pur- 

 poses. These will make good 

 exhibit pieces to place in shop 

 windows as a proof of ability to 

 develop and make unusual 

 pieces. The patterns for all of 

 these six elbows are developed 



torn B. It will be necessary to develop the 

 pattern for one piece of the elbow, the same 

 as in the round elbow. In this case the 

 pattern is developed for the part marked A . 

 The seam is indicated in the center of the 

 short side of the elbow (see bottom view B). 

 Moving clockwise around the bottom view, 

 number each point I, 2, 3, 4, 5 and 6 as 

 shown. Lay off the base line C-D, finding 

 the correct length by taking the distance 

 1 to 2, 2 to 3, 3 to 4, 4 to 5 and 5 to 6, from 

 the bottom view B. Run these points up- 

 ward from the base line as indicated by the 

 faint lines, then from the joint line project 



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The square, the oblong and the oval elbows are in common everyday use and the method for their 

 development is exactly the same as that for making the pattern for the ordinary round elbow 



in exactly the same way as the pattern for 

 the ordinary round elbow illustrated in the 

 first article of the series (June, 191 7, issue). 

 The square elbow, Fig. 1 , is the simplest 

 to make. First, draw a front view of the 

 elbow shown at A and then draw the bot- 



the points of intersection to the pattern, 

 marking each point with a cross where it 

 intersects the similarly numbered line com- 

 ing up from the base line C-D. Connect 

 these crosses with straight lines and the 

 result will be the pattern as shown. Allow- 



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