Sheet Metal Working Simply Explained 



III. — One-piece pattern for making 

 a twenty - sided steeple ornament 



By Arthur F. Payne 



Assistant Professor Manual Arts, Bradley Polytechnical Institute 



THE problem for the development of a 

 pattern for a twenty-sided finial is 

 very interesting. Glancing at the 

 drawing of the finial it will appear difficult 

 to lay out a one-piece pattern of tin in 

 such a manner that when it is bent up it 

 will take the shape shown in the finished 

 drawing, but if the drawing is given close 

 attention and study it will be readily seen 

 that all of the twenty faces are of the same 

 size and shape, and that each face is an 

 equilateral triangle; that is, a triangle 

 having three sides the same length. 



It is necessary to get first a true pattern 

 of one of these faces. The No. 4 face is 

 the only one that is lying flat on the 

 paper, all the others are apparently re- 



To lay out a pattern for such a finial it 

 is necessary to know first how large the 

 finial is to be when finished. For conven- 

 ience of this problem we will consider one 

 10 in. in diameter at the widest part. The 

 steps taken in order are as follows: (1) 

 Draw a circle 10 in. in diameter — see 

 dotted circle in upper view. (2) Divide 

 circle into five equal parts and connect 

 these points with straight lines. (3) Pro- 

 ject one of these lines down for the top 

 line of the triangle 4 of the front view. 

 (4) With a pair of compasses and a ruler 

 draw the triangle 4 with all sides equal in 

 length. This is the true pattern for one 

 face. (5) Draw this pattern as No. 4 

 face in the "full pattern" and then draw 



A pattern in one piece having twenty faces, each of the same size and shape, or an equilateral 

 triangle, to make a twenty-sided finial to be shaped from sheet metal for a steeple ornament 



ceding from the surface of the paper. 

 When a face is lying flat on the paper, as 

 this one mentioned, it is called "lying 

 in the plane" of the paper. All such faces 

 are true patterns. 



the other faces exactly as shown in the 

 full pattern. 



Cut the pattern out of tin and proceed 

 to bend on the dotted lines. It will be 

 necessary to bend the top and bottom row 



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