HYDRAULIC RIVETING.

Star (Christchurch), Issue 3358, 13 January 1879, Page 4

HYDRAULIC RIVETING.

{By the Lyltelton Times Special Ecpovlev.) There are now lying in tho yard at Mr John Anderson's Canterbury Foundry bouic massive pieces of machinery, which are destined to effect a highly imp'ortant change in tho production of large boilers and any othor iron •work in which much rivoting haa to be done. In articles which have from time to time appeared in the columns of this journal, the ordinary process of riveting has been often referred to, and the red hot bolte, tho labour .of tho hammermen, and the incessant din produced by their work have been duly described. Tho pieeesof machinery in question will, when erected, form ono of the direct tiding hydraulic rivoting machines, respecting which Mr Ralph H. Tweddell, on June 4, 1877, read an elaborate paper before the Society of Engineers, and evoked a highly interesting discussion. The great object which Mr John Anderson has in view in importing and fitting up this special apparatus, ia to enable him largely to extend his operations, and to compete successfully with foundry masters in other parts of tho world. There is, however, another advantage to be gained, which is tho regularity and better quality of the work done by hydraulic power »9 compared with hand labour, or even as compared with steam power. In hand work there is tho succession of hammer blows, changing to a certain extont the condition of friio boiler plate along tho lines of rivets ; in fitcam riveting thero is a sudden and violent blow which shakes everything, but in tho case of hydraulic pressure there is simply a steady squeeze, acting just at the right moment, and with the exact force of 25 tona on each rivet-head. With this immense force the plato3 aro nipped together, and the hot rivet is closed upon them, to make tho joint still firmer as tho cooling procuss goes on. Cold riveting has bcon attempted, both in America and in England, at works in Gloucester. The experiment has Leon pronounced a failuro, attributable to tho quality of the iron. In the United States, however, some high pressure boiier3 made of thin plate3 havo been cold riveted, and with good results, especially a3 for cold work a rivet of inferior iron could not possibly be used. In tho apparatus which Mr Anderson is About to erect, thero is a massive frame trork, ivliich is carried to such a height tliat a long boiler can. be suspended perpendicularly within it, and, by means of a eeries of pulleya and counterweights, be topt at any desired elevation. Within the framework, near one side, there rises up from the ground an enormous pair of jawa, hinged in tho manner of strong shears, and armed with a single tooth in each jaw — the punch and counterpart for closing up tho rivet. Tho motive power for these jaws is supplied by a liydrauuc pump, worked by pulloy and strap connection with a steam-engine. The power of tho hydraulic pump is augmented by an apparatus known as tho accumulators. There is a vertical pillar, up and down which slides a cylinder, loaded with weight riuga. Tho pressure of the water is Bufliciont to raise tho cylinder and rings, and as theso riso tho mas»ive jaws open. The process being reversed, tho weight of the cylinder and rings acting on the water imparts to it a pressure of 15001bs to the square inch. Tlioaccumulator,havingoniya email area, will if requirod fall for a coneiderablo distance dowu the central pillar, and euch distanco will bo largely in excess of the movement of tho riveting jaws. Thus, ■while tho ram carrying the die of the rivoter travels two and a half inches, tho cylinder and rings, weighing some fivo tons, will fall 24 inches. The result of this arrangement is tliat owing to the suddenly* arrested fall of the weights, the effect of a sharp blow is obtained in the ram of the riveter, as well as the steady pressure characteristic of hydraulic power. To this combined feature is due the success of hydraulic rivoting, especially for boilers. The rise and fall of the cylinder, and the resulting squeoze-blow, is by no means a slow operation, and carof ully conducted experiments havo shown that great speed of working is quite consistent with tho use oi hydraulic power. A speed of 20 rivets per minute can be obtained; or, in straight forward work, a steady average of eight pci minute throughout the day will bo tho rate of progress, and from 1800 to 2000 rivets it very irregular work. At the Stratford shops of tho Great Eastern Eailway, tho riveting has long been dono by hydraulic power, and in tho discussion at tho meeting of the Socioty of Engineers which has been referred to, the result of 18 months' experience was given. The speaker said he had inquired how lnanyfaUurea hadoccurred with rivets put ic by the hydraulic lnriclnno, una'cno most that the workmen would admit was that one rivet had leaked in ono boiler. With regard to the «conomy of using tho machines, he had found that with one riveter, ono labourer) and ono boy, 300 boiler rivots could be put in in one day, while for doing the same work by hand thoy would requiro twdvo men and four boys. With the plant which they had in use and intended to order, they would be enabled to turn out 56 locomotivo boilers in a year, with 050 rivets in each. Allowing .interest at 6 per cent., tho saving in labour would bo £470 per year, and that ostiunatc put entirely out of consideration tho question ol lime. Work is coinmoncod by rivoting a ring tc one of the end plates of tho boilor, the tackle which suppjrts tho work and communicates with tho compensating weight, allowing of any given point being introduced botween the jaws of tho hydraulic raiu. When this section has been completed, another ring is added from beneath, aud the boilor gradually rises until the whole is completed. In working the hydruuliu jmuip, comparatively littlo water is roouirod, siucn it is used jjguin and again. Nor is any difficulty experienced from frost, even during tho most eevoro winters. Mr Tweddell has Bont machinery to Eussia, and ovon in that region of frost-bitton noses all difliculty was overcome by placing tho pipes in the workshops from 18in to 2ft underground, aud by mixing a littlo methylated spirit with tho wator. Elsewhoro a gallon of glycerine put into about 300 gallons of water has effectually obviated all difliculty from frost. Punching, shearing, &0., aro equally well dono by hydraulic power, tho workman having perfect control ovor tho movemont of tho ram by mean3 of tho vulvo handle. There is no noise, no dirt, no dust. Thero is no danger to tho workman ; the wear and tear is in exact proportion to tho work dono, for if no work is boing dono nothing is moving. Enough has now been said to give some idea of the advantages of hydraulic powor in iron work, aud to show that Mr John Anderson's new venturo is but another strido in the steady progress which has marked tho career of tho Canterbury Foundry.