Metal Working Exercises 



49 



Method 4. Two wires, with ends touching, but not long enough 

 to overlap. 



FIG. 40. 



FIG. 41. 



Take a piece of copper foil, and roll it round a needle of the 

 same diameter as the wire. Cut about i" off this " sleeve," tin the 

 inside well, and ends of the wires. Fill the sleeve with solder, heat 

 strongly over a bunsen, and slip in the end of each wire in turn 

 before the solder solidifies (Fig. 41). 



Wires connected at an angle. Method 5. By twisting the 

 second wire in a close coil around the first, a good joint is made ; 

 but, if any vibration is likely to disturb the junction, the joined wire 

 will probably break off at A (Fig. 

 42). For this reason a third 

 wire may be coiled, as sketched. 



Wires at acute or obtuse 

 angles may be treated as above, 

 and bent before the third wire 

 is wound on. This will usually 

 be sufficient. 



Multistrand Wires. These 

 wires are usually much more 

 easily treated than single ones, FIG. 42. 



as the strain of the joint is divided 



among the strands instead of coming at one point. Wires of this 

 class have 3, 7, 19 or 37 strands, for the reason that this number is 



/ A^A_A^A,^A. \ 



QCQQD 



19 



FIG. 43. 



the most natural for securing a maximum number of strands in a 

 minimum area (Fig. 43). 



