Passing Comments
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Trading With the U.S.S.R.
DESPITE all the political disturbances between the U.S.S.R. and some capitalist countries, the reciprocal trade between Russia and Finland, Britain, France and the Federal Republic of Germany accounted for about 40 per cent, of the total for such countries. In comparison with 1950 the trade with these four has more than quadrupled.
For 1957 the total with all capitalist countries was 8,757m. roubles, of which Britain's share was 1,204m. That with Finland was slightly more, whilst Germany's share was 533m. and the trade with France 458m. It is interesting to note that compared with the previous year, Britain's percentage increase was the greatest.
LR.T.E.'s Successful Occasion
HE could not see any reason why some members of the institute of Road Transport Engineers should not act as inspectors in connection with the " vetting " of 10-yearold vehicles, although they might not be able to undertake any repairs necessary. This was suggested by Sir Gilmour Jenkins, K.C.B., K.B.E., M.C., in proposing the toast to the Institute and its president at the recent I.R.T.E. annual dinner.
Occasionally people had remarked to Sir Gilmour that they thought it unnecessary to have more representative bodies than those major ones covering the mechanical, electrical and civil engineers. He, however, was of the opinion that others more closely connected with particular activities could be most useful and valuable, and he congratulated the I.R.T.E. on its successful development and the great work it was doing in many connections.
Thanking Sir Gilmour, the president, Mr. G. Mackenzie Junner, referred to the hard battle for official recognition which the foundation committee had to undertake until they were able to produce adequate "proof of need."
The function was held for the first time at the Piccadilly Hotel and was attended by nearly 300 members, guests, and representatives of the industry.
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Vision and Safe Driving
N American survey of vision and traffic safety, r-kA published in The Sight-Saving Review, contains much of interest on this subject. Some 75m. people are licensed to drive in the U.S.A., and of these 6m. are examined annually, a visual examination for renewal being enforced in 13 states, the ages of those concerned varying at different places from 70-80.
Drivers with one eye are accepted everywhere if that eye has a full field of vision and various requirements as to corrected acuity. No tests are made for night vision or resistance to glare, although some drivers are restricted to the daylight hours.
Ordinary screening tests are conducted rapidly with relatively simple and inexpensive apparatus, by lay personnel of limited training, but in three states an applicant who fails can be referred for further investigation to a specialist of his own choice.
The driving-research laboratory of one state claims that 60 per cent. of the general adult population require glasses, but only 30 per cent. use them, and of these, another 30 per cent. have glasses which are no longer correct. Poor vision which cannot be improved sufficiently occurs in 5 per cent.
The American Association of Motor Vehicle Administrators recommends that the driving licences of those requiring glasses should be stamped with the wording "Must wear corrective glasses while driving." The " corrective " is added, otherwise plain or sun glasses would technically meet the requirements.
It has been discovered that a driver can perceive an unexpected obstacle only half as far away as in the case of an expected one.
The importance of safety in driving is shown by the fact that one car in 12 is involved in a serious crash each year, and in 1957 traffic deaths numbered 40,000, the rate being twice as heavy in rural areas as in the cities. Nonfatal accidents were a hundred times greater and a fifth involved children, mainly in the age group of .5-6 years.
Development in Chemical Milling
CHEMICAL milling as an alternative to machining has been in operation for several years in the shaping of aluminium, magnesium, titanium arid steel sheets, rods and tubes. In the latest developments the process has been extended to castings of all shapes.
The process is that of etching in a chemical bath, and in its application to mass-production methods, as many castings as the bath will hold are dealt with collectively, and not individually as in the case of machining.
Now a masking material has been introduced for applying to parts of the casting which are not desired to be acted upon, thus widening the possibilities of the system.
The chemical solution of the bath must be compounded in conformity with the metals forming the alloy of which the castings are made, each constituent being capable of dissolving the grains of the metal of which it is a solvent. The action of the solvent takes place at microscopic level, removing the individual grains of the metallic surface, which remains chemically unchanged, nor are physical or chemical properties altered. The average rate for chemical milling provides a reduction of 0.001 in. per min, and the action can be controlled to tolerances of plus and minus 0.003 in.
Surface finish is generally improved by the process; aluminium is around 300 r.m.s. and steel casting surfaces are approximately 125 r.m.s.; these results depend upon the condition of the casting before treatment by milling. Manganese and titanium alloys give also a finish of 125 rims., and die castings result in better surfaces than do sand castings.
To conform to sonic of the necessities of foundry technique regarding metal flow and cooling, castings are often heavier than would be otherwise necessary; the use of chemical milling may permit of designing to take advantage of the possibilities of this.
It may seem difficult to predict the results of chemical milling, but actual results show that the conditions vary about as much as those in machining. Good, consistent results can be obtained on any group of parts if the casting alloys be properly controlled. The composition of the milling bath is also subjected to chemical control of the constituent&