Metal Working Additional Processes 59 



The flat pane of the hammer is used at first in riveting, 

 the tail being hammered lightly across the top from A 

 to B, Fig. 55, until a somewhat flattened head is made 

 upon it, when it may 

 be hammered more 

 heavily, and finally 

 flattened to the surface 

 of the joined plates. 

 During hammering, the FlG ss ._Ri ve t in position ready for closing, 

 plates should occasion- 

 ally be struck in order to ensure that they do not " creep " 

 up the rivet, and it is well also to watch that the rivet head 

 and plates are touching all the time. 



No difficulty is to be anticipated in making use of this 

 process with success. 



A word may be said with advantage concerning the repair 

 of china by " riveting." Though badly named in this connection, 

 a metal stay is frequently of great service in the union of 

 porcelain, as a supplement to a cemented joint. To make 

 this, a hole is drilled (see Glass Drilling) well into the china 

 article, about J" from the joint, and a piece of hard copper 

 wire (or better still, tinned iron wire), No. 18 about i^" long, is 

 bent very sharply at right angles, " from each end. This 

 wire is then placed at right angles across the proposed joint, 

 and the ends cut down until, when one end is put into the 

 drilled hole, the wire lies flat on the article. A second hole 

 is then drilled in the china, opposite the first, a shade out of 

 reach of the wire stay the exact amount being learned only 

 by experience, it is really the maximum the wire will stretch, 

 so that when drilled, the stay may be sprung into place, and 

 will actually pull together the broken surfaces. Several such 

 stays are prepared, not less than three as a rule. The broken 

 edges are then treated with a suitable cement, placed to- 

 gether, the stays inserted, and the remaining spaces in the 

 drilled holes at once filled with plaster of Paris. 



This method is equally applicable to glass. 



Brazing. This operation is one not usually conducted in 

 the laboratory, owing to the difficulty of securing sufficient 



