658 CONSTRUCTION OF BINDING SCREWS; 



manner shown at B in the figure, they fulfil every requirement. 

 The flat terminal pieces of the wires are simply placed between 

 the end of the screw and the inner side of the clamp, and the screw 

 is turned until the terminals are held with firm pressure. 



The other binding screws are made of brass wire, 10 or 12 mm 

 thick, of which pieces of suitable length are cut with the metal saw 

 or the narrow cut edge of a flat file. Holes are drilled through the 

 pieces, nuts cut in them with the smallest tap, and the necessary 

 screws for them are made of brass wire. The handles of the screws 

 are made by softening the wire and bending one end into the 

 form of a ring ; the portion of the wire which is to be left straight 

 being clamped in the vice, the projecting end is brought into the re- 

 quired shape by bending with the round pliers and hammering 

 with the mallet. : As the wire is rather thick, it is usually not 

 possible to close the ring by this operation, but by proceeding as 

 has been described when making a pinchcock (see page 21), a com- 

 plete ring will be formed. 



Fig. 337, (7, is the section of a binding screw for connecting two 

 wires : a hole into which the ends of the wires are inserted is drilled 

 lengthwise through the little cylinder of brass, and the two screws 

 for clamping the wires enter from opposite sides. 



Fig. 337, D, serves for connecting a flat terminal with one of wire. 

 The hole for the wire reaches from one end to the middle ; for the 

 reception of the flat terminal, a slit is cut down with the metal saw 

 from the opposite end of the cylinder, about 12 mm deep. 



The forms E and F in the figure are intended to be attached to 

 the wooden parts of the apparatus used. E serves 'for clamping 

 flat strips of metal, and differs from A only in having the lower part 

 longer, so as to be capable of being fixed by means of two wood- 

 screws. In order that the flat heads of the screws may 

 not project, the entrance of the holes in the clamp must 

 be enlarged and made funnel-shaped. This operation 

 is performed with the * rose counter- sink ; ' fig. 338 

 shows the conical cutting portion of it with its tri- 

 angular facets. The handle may be fixed into a brace 

 or simply worked by a strong drill-bow, exerting mode- 

 FIG. 338 rate pressure upon the instrument until the funnel- 

 (rea size), g^pgfl entrance is of the requisite width. 



In form F the upper screw serves for clamping wires, which are 

 inserted from the sides into a horizontal hole. The lower screw is 

 used for attaching the binding screw to the apparatus, which may 

 be done either by simply screwing it like a common screw into a 

 hole made in the wood, or by boring, from one side of the piece of 

 wood, a hole through which the screw just passes, and, from the 



