ADDINGTON SHELLS.

Sun (Christchurch), Volume II, Issue 617, 1 February 1916, Page 8

ADDINGTON SHELLS.

.— TRUE TO SPECIFICATION. Prett.i Association. WELLINGTON, January 31. In its interim report, the Munitions Committee, which was set up at a conference of engineer; held: last September in Wellington, at the j request of the Minister of Munitions, indicated, inter alia, that the bodies! of shells could be manufactured in i New Zealand, provided the proper| steel and copper bands could be obtaincd. In order to make a practical, demonstration, a small quantity of! steel was procured from Broken Hill. Professor R. .1. Scott, ofj Christchurch, chairman of the com-; mittee offered to undertake to turn' out an experimental batch of shells, and for this purpose Mr E. H. HileyJ General Manager of Railways, placed at his disposal the services, of Mr Jackson, Chief Mechanical Engineer, and the staff and machinery I of the Addington Railway Workshops. It is interesting now to learn that 18-poundcr explosive shell bodies, true to the War Office specification, have been turned out, the finished article presenting a decidedly workmanlike appearance, reflecting great credit on those concerned with its manufacture. THE PROCESS DESCRIBED, IMPORTANT QUESTIONS INVOLVED. ISptcinl to The San.} WELLINGTON, January 31. Referring to the manufacture of 181b high explosive shells at Addington Workshops, the authorities slate! that the steel is supplied in Sain bars by the Broken Hill Company. The whole of the formation of the shell [ is effected by machinery, no forging or pressing or heat treatment being required. Test specimens are cut! from the steel bars, and on these' j passing exacting physical tests the [bars are straightened and cut up into lengths, each of which will I make a single shell. These blanks! \ are drilled to form the cavity for thei l explosive, the cavity being subsc-j i quently carefully bored and then ex-, | posed to a sand blast, which gives the exceedingly smooth finish necessary for safe handling where high j explosive charges are used. As a i further protection the interior of the i shell is varnished. The mouth is j screwed to take the standard fuse, ! all measurements of this part being I made to the thousandth part of an i inch, the extreme permissible variai liou inside being .(JOG. Such work j can be accomplished only with the assistance of gauges and the most j accurate of tools, and to enable the shell to be made some 00 gauges had first to be manufactured by the Raili way Department, each in all portions accurate to the thousandth part of an inch. The body of the shell is turned and the nose ground, the per- ! missible variation in diameter being! lone-hundredth pari of an inch, bul .accuracy comparable with that at the fuse screw is required in the copper I driving band, which serves the ! double purpose of a gas check and 'the means of rotating lite projectile, 'by being forced into the riding of the gun. The base of the shell is recessed, and a base plate of steel, I the grain of which is Iranvcrsc to that of the body of the shell, is ; screwed and cemented into it. This is a precaution against the chance ! ignition of a bursting charge by Hash I through an undetected flaw in the ] base of the shell. "Of course it must be rememberjed," said Mr Myers to your correspondent, "that if we are to proceed ! vigorously with the manufacture of i large quantities of these shells, and to be of any real service, the RailI way Department would necessarily | have to set aside a large portion of its important work of making carriages and maintaining the present : rolling slock, while if the work were undertaken by outside firms the assembling of their plant in central localities would have Hie effect of interfering to a large extent with | the making of freezing works ma- , Ichinery and dairying machinery, | which arc so necessary for the carrying on of our important industries. ! '< ft will be seen, therefore, that the •'problem is very weighty, and will i require most careful consideration," Information in the hands of the ■ Minister of Munitions, together with the result of the experimental manufacture, will enable him to place the matter before Cabinet, who will now consider the whole question.