MAKING BOMB CASES

Southland Times, Issue 24425, 3 May 1941, Page 6

MAKING BOMB CASES

CITY’S CONTRIBUTION TO WAR EFFORT

HIGH-CLASS WORK BEING

DONE

Munition making is now being carried out in many countries of the British Empire. Australia and Canada are making impressive and increasing efforts, and New Zealand is also rapidly falling into line. Necessarily New Zealand’s contribution cannot be as large as that of either Australia or Canada, but there is every indication that, judged on a population basis, New Zealand will do her full share. The New Zealand-made tanks which appeared in the big parade in Christchurch on Saturday were an indication of this. Munitions are now being made _in several centres of New Zealand, including Invercargill, where two firms are engaged on the work of finishing off the cases of Stokes mortar bombs. This bomb is probably the most effective of its kind ever invented. It is possible to fire the bombs so quickly that during the last war the Germans nicknamed the Stokes mortar the English sausage gun. Although a bomb is only a metal case filled with an explosive, it is actually the product of several highly technical engineering processes that demand a great degree of skill. Symmetry is essential to the highest effectiveness. This means that the bomb case must be of uniform thickness all the way round and the achievement of this requires great skill and, of course, the right sort of plant, for a very exact degree of uniformity is demanded. The job of making a properly finished case from the rough casting involves the use of 10 different machines, and as the making of Stokes bombs in New Zealand began from scratch a considerable amount of experimentation was needed. Now, however, partly through a process of trial and error satisfactory results have been achieved. As an example, two of the slowest processes, those of roughing and finishing, have been so speeded up that in each case the time taken is now only a quarter of what it originally was. The Invercargill workshops are now ready to go into full production of a highly satisfactory article. An expert who saw samples of bomb cases from Invercargill pronounced them as being as good as any made anywhere in the I world. The only trouble is the supply of .rough castings. These are being made in Dunedin, and so far the supply has not been sufficient to keep the I finishing machines running at their maximum capacity. The bomb cases are not filled in Invercargill. That job is done elsewhere, but the main problem of bomb manufacture is the production of a satisfactory case, and that problem has been solved in Invercargill.