Polytechnic Association. 9(59 



"Mr. Adamson lias found, by direct experiments, that a plate rolled 

 very hot, and a ' black-rolled ' plate, will expand at such different 

 rates when heated as to strain the rivet-seams ; and, when tested at 

 the same temperature, the rates of elongation vary so much that two 

 such plates, when joined, will never take the strain equally. The 

 process of annealing is, therefore, carried on at the works, and is 

 combined with that of bending the plates. 



" After the process of bending, the plates are fitted together by 

 means of a few temporary bolts which pass through holes previously 

 punched through them. The diameter of these holes is much less 

 than that of the rivet holes, in order that they may be drilled out to 

 their proper size for riveting, after they have served their temporary 

 purpose. 



" The plates are next put under a drilling frame having six head 

 stocks, with horizontal drills, all placed radially, and so arranged as 

 to be adjustable to the diameter of each shell. The holes are drilled 

 with great speed and accuracy, six at a time, and through both super- 

 posed plates at the same time. 



"The plates, being drilled together, never change their relative 

 position, and each rivet is thereby made an absolute mechanical fit. 

 * * # # Riveting is effected by machinery, wherever the shape 

 and position of the parts will allow the application of the 'machine. 

 Mr. Adamson considers a machine-riveted seam superior to one made 

 by hand, particularly when steel rivets are used ; as, with hand-rivet- 

 ing, numerous blows with the hammer cause that degree of brittle- 

 ness called ' hammer-hardening.' The machines used for riveting at 

 Newton Moor are of Mr. Adamson' s own design. They act by rais- 

 ing an adjustable weight through a series of compound levers, this 

 weight actuating the riveting die by its sudden descent. This princi- 

 ple insures the exertion of an exact pressure upon eacb rivet, and this 

 pressure, whilst it can be adjusted to each kind of work, cannot be 

 altered by the workmen tampering in any way with the action of the 

 machine." 



By following this plan there is, first, a trial made of the quality of 

 iron in every plate which is used. After the quality is ascertained, 

 every sheet is annealed and bent into the required form, while soft- 

 ened by the heat, so that its strength may not be reduced by that 

 operation. Drilling the rivet holes, in the manner described, not only 

 leaves ten per cent more iron between them, but leaves the whole in 

 much better condition. When the holes are punched they are 

 always so irregular that for five-eighth rivets they are usually made 



