UTILIZATION OF ELM. 



21 



material for bending, considerable difficulty is experienced from 

 splintering and breaking because pieces as much as 2 inches square 

 must be bent quite sharply at right angles. Figure 7 shows some of 

 the common bent forms used. A good supply of satisfactory elm 

 material is important to automobile body makers, for they consider 



Fig. 7. — Some common forms of elm bent-wood pieces used in automobile bodies. The most exacting 

 demands are made upon the wood by the forms a and 6, used for back rails, on account of the sharp- 

 ness of the bends. The two common modes of failure in bending are illustrated in b, which is a cull 

 piece; in the right-hand bend at x splintering tension has taken place, and the left-hand bend shows 

 compression failure at y, the fibers of the wood being folded over. The forms c and d are not so difficult 

 to make, since the bends are more gradual. 



that no other wood can replace it for the back rails, wheel housings 

 (where thin material is bent in curved form), and other small bent 

 pieces (fig. 8). Elm from southern Michigan is considered not so 

 satisfactory for these uses as that from the northern part of the 

 southern peninsula. That from the extreme southern States is con- 



FiG. 8. — Partially assembled wooden framework of automobile body. The bent-wood piece (a) forming 

 the back rail of the rear seat is soft elm, and also the circular piece (6), above where the wheel is to be 

 located. The triangular blocks (c and d) to the right of each side door at the base are rock elm. 



sidered inferior because of the presence of numerous defects. Ma- 

 terial is secured mostly in the form of 1 and 2 inch lumber, and a 

 large supply is usually kept on hand. Many automobile body makers 

 report a purchase price of from $40 to S50 a thousand for various 

 grades of white and rock elm. Thirty-eight dollars is the average 

 price reported by a considerable number of such manufacturers, which 



