42 



ELEMENTARY WOODWORKING 



Bung-head wire nails, or brads as the smaller sizes 

 are called, have very small heads, which allow the nail 

 to be sunk below the surface. This is done by means 

 of the nail punch, or set, and is necessary when the sur- 

 face is to be planed after the nailing. 



26. Screws. Screws are much used, and allow the 

 pieces to be readily taken apart. They are divided 

 into two classes, flat head and round head, and are of 

 steel or brass. Steel screws are either N;ued or hrigJit. 

 Bright screws are polished and blued screws are ^^ro- 

 duced by treating the bright ones with heat or an acid. 





B 



C D 



Fig. .55. Methods of using Screws 



Fig. 55 shows a flat-head screw at a and a round-head 

 at b. Flat heads are used for the more common work 

 where it is desirable to have the screw head flush (even) 

 with the surface or below it, while round heads are used 

 where this is not necessary. In the latter case round 

 heads are used partly because they are more ornamental. 

 Flat heads must always be flush or below the surface, 

 and in all but the softest woods it is necessary not only 

 to bore a hole for the screw, but also to countersink it 

 with a countersink bit in order that it may receive the 



