Opinions from Others.
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British Interests in the Argentine.
The Editor, THE COMMERCIAL MOTOR.
1,205] Sir,—In your issue of 1st September, you have a very-interesting article headed " British Interests in the Argentine," but on reading through that article you do not seem to warn British firms of the very-serious risk they run in doing business in the Argentine supposing they want to collect money from somebody, for example, who has not met their bills. I note you rather recommend that credit should be given to open up business. Is that really wise, if the method of collecting—supposing the people do not keep their undertaking—is so difficult to be practically sure you will lose your money ? Perhaps you would get your correspondent to give some little consideration to this side of the question.—Yours faithfully,
S. F. Enos.
The article was from the pen of Sir John Bonn. Manufacturers and traders will, no doubt, especially after Mr. Edge's remarks, take all precautions. A general intimation, that credit is expected, does not preclude specific inquiry as to character.—ED. I
The Proper Lubrication and Protection of Ball Bearings. The Editor, THE COMMERCIAL MOTOR.
[1,206] Sir,—In your issue of 31st March last, there appeared a letter from Mr. Alexander Duckham on the subject of ball bearings and their lubrication. In that letter, he criticized the remarks which Colonel Crompton had made in connection with Mr. I'. B. Browne's paper. Mr. Duckham concluded by advancing a theory that the peculiar black marking, which starts on the race at some slight distance from the point of contact, may be due to some electrolytic action. This black marking has been a bugbear to ball-bearing manufacturers, because it was wont to appear while the bearings were stored in a preservative medium and packed in store. We had already done what we could to help Mr. Duckham in his experiments, but we were glad to adopt his suggestion that we should make still further experiments to see whether a preservative compound of high dielectric strength, and which had a minimum coefficient of saturation of water, would obviate the marking in question. We therefore prepared a number of bearings dressed with various compounds, placing them in positions where they would be most-severely tested by the presence of moisture. At the end of some three months, we found that the bearings and balls dressed with the material, which Mr. Duckham's firm had prepared as possessing the highestpossible dielectric and non-absorbent properties, had no sign of the black marking or etching referred to above, whilst the other bearings, which had been dressed with -the usual rust preventives and greases, showed this marking most distinctly. These latter preservatives and the greases all had a marked tendency to absorb moisture from the atmosphere, and some of them contained metallic salts and fatty acids, which still further tended to reduce their dielectric strengths and power of resisting the absorption of moisture. When making these experiments, we had hoped to be able to make some definite statements as to the cause of this phenomenon of black marking, but unfortunately the evidence is only negative, and all that we can say is that when Messrs. Alexander Duckham and Co.'s non-absorbent insulating grease is employed the marking does not appear.
The great importance of most-careful treatment of hardened and ground steel parts is, perhaps, not sufficiently recognized by engineers. The grinding process
• leaves the surface of the metal unprotected, and very :susceptible to external chemical and electrolytic influences. Ilf a ball bearing is filled with one of the ordinary lubri eating greases, sometimes known as cup grease or solidified oil, or again as rust preventive, such must absorb its water of saturation, and an etching effect will commence upon the balls and race, even though the bearing be wrapped in oiled paper and kept in what is considered to be a dry place for, as long as such a grease is employed, it will absorb its quota of moisture from the atmosphere. Until engineers fully realize the great importance of keeping moisture and metallic salts away, there will be a proportion of failures with ball bearings. To minimize such failures, we always recommend that not only the ball-bearing parts, but the whole of the homing in which they are mounted, shall he completely filled with a preservative medium. It is, we know, very difficult to have this carried out, because the fitters who do the work look upon it as a waste of grease, and fail to realize that very little—if any—of such grease is required afterwards. The object, of course, in filling the whole of the housing is to exclude the moisture in the atmosphere as difference of temperature will cause the condensation Of the moisture in the air, both upon the grease and, more especially, on the parts of the bearing. Another reason for keeping the bearing full of grease is that it prevents circulation in the housing of air, which would carry with it a certain quantity of dirt. Ball bearings, therefore, should be mounted in housings which are crammed full of grease, and, further, leather dust washers, or other suitable means, should be employed where the shaft protrudes through the housing. A Stauffer-type lubricator should be fitted, and a certaix amount of grease be occasionally forced in until it commences to exude past the dust washers. If these precautions are taken, and the grease which we recommend be used, not only will the black marking and etching, but also rust of the bearing parts, be prevented, and dirt and dust will he excluded.
This non-absorbent insulating grease is being put on the market by the firm of Messrs. Alexander Duckhaut and Co., of Millwall, who will call it " Hoffmann Ball Bearing Grease." We are in no way interested financially in the manufacture or sale Of this grease, but recommend it solely from the experience we have gained with it.—Yours faithfully,
THE HOFFMANN MANUFACTURING CO., LTD.
G. F. Barrett, Director.
Chelmsford.
" Flats " on Tires.
The Editor, TEE COMMERCIAL MOTOR.
[1,207] Sir,—I have been interested to read the various letters, which have appeared in recent iseuee of THE COMMERCIAL MOTOR, On the subject of " flats " on front tires, and the most reasonable explanation so far seems te me to be that given by " R.A.W." (letter No. 1,200), is which he attributes their development, to badly-worn leading-wheel bushes. The other letter which appeared ix the same issue as that from " R.A.W.," written by a correspondent signing himself "Traveller," might explain the matter were the presence of " flats " confined to the off-side front tire only, but, in my experience, they occur equally on both tires, although, in the vehicles of which " Traveller " speaks, it is probable that the steering gear is not maintained in the highest state of efficiency, and, by reason of a large amount of back lash, he might get the " flats " of which he speaks. In my opinion, one of the chief reasons for the formation of " flats" is that the wheel bush is not bored exactly at right-angles to the vertical axis of the wheel, and, therefore, the wheel wobbles and slips sideways over the ground. Another reason, and one which, in practise, I have found to cause " flats," is incorrect "setting " of the two leading wheels. When set for the straight-ahead position, the two front wheels should be absolutely parallel with each other; if this condition is not obtained, the wheels tend either to run in towards each other, or to run away from each other, and, whichever condition may prevail, there can be no doubt that the treads of the tires continue to follow the rolling lines until the rubber is stressed to a maximum; one or both the tires will then slide sideways over the surface of the ground, until the stress in the rubber is relieved. Once a " flat" has been started on the tread of the tire, the probability is that the side-slip will recur each time the "flat " touches the ground while the tire is in a state of stress, in preference to sliding on an unflattened section of the tire. My statement is not based on assumption, but from actual observations with rubber tires on lorries taking up to four-ton
loads.—Yours faithfully, GEOFFRY WALLACE. Richmond, 9th September, 1910,
Miniature Vans Wanted.
The Editor, THE COMMERCIAL MOTOR.
[1,208] Sir,—I hope your call for more attention to the matter of well-built small vans will meet with an early response at the hands of manufacturers. As you point out, there is a remarkable gap between the tricycle carriers now on the market and any 10 cwt. vans of proved commercial worth. It seems to me that there is plenty of time, between the present date and the commercials-abide show at Olympia next March, for a useful and successful attack to be made upon designs which will comply with the specification that you have sketched. May I be allowed also to enter a plea for large-diameter wheels. Any maker who uses 22 in. wheels upon such a van will be courting trouble, and it certainly presents no insuperable difficulty for wheels of at least 30 in. in diameter to be fitted, without gearing the vehicle to speeds which are unnecessary. I look for a top speed of 17 or
18 m.p.h.—Yours faithfully, " ROTAX."
Users Experiences: the Life of Rubber Tires for 12-ton Gross Loads. The Editor, THE Comtaxamar., MOTOR.
[1,209] Sir,—The somewhat-lengthy break in the record of my experiences as a motor-wagon carrier is due to. the fact that I have been endeavouring to introduce a new factor into the business. I have, in fact, been trying to arrange for a reasonable summer holiday for the staff. So far as I am concerned, the result has been somewhat questionable, for, when anyone is away, I have to climb down from my exalted pedestal, of a little tin god, and to do some real hard work. I have no doubt ray men have fully appreciated the humour of the situation.
We have had a. very-busy tin ie this summer ; the wagons have got through a tremendous amount of work, and they would have done this with a considerablygreater degree of comfort if our customers had only shown a little more consideration to us. As it is, I find that the public will often refuse to take any steps themselves to meet " a rush order" promptly, if they feel that there is the smallest chance of the carrier's saving the situation for them at the last moment.
We have just completed 10,000 miles on a set of Polack rubber tires, carrying a gross load of 12 tons. The tires, which were fitted at the beginning of the year, are still in use; they are, however, nearly worn out. The difference between the effect of winter and summer weather upon the tires was very .marked ; the hot bright weather seems to cause them to wear dawn rapidly, as compared with the colder and wetter weather which prevails in the winter. I think the best results will be obtained by having them fitted at such a time of year that they may end their existence during the winter months. There is no doubt that the life of rubber tires depends largely upon the consideration they receive from the driver in starting and stopping, in turning corners, and as far as possible in avoiding tramlines. The financial return they bring to their owner is a negligible quantity, and does not corn
pare favourably with steel tires, even allowing for winter stoppages with the latter. At their present price, the convenience of rubber tires is their greatest charm, and in this respect alone they are worth the careful attention of all users of heavy motors, for there is no doubt in my mind that the financial difficulties will eventually adjust thernselve.s. The effect which rubber tires have upon the surface of a road appears to he even more disastrous than that of the steel tire, owing to the sucking action of the rubber, and I fancy that before long road surveyors will recognize that a steel-tired heavy motor is by no means their worst enemy.
During the past summer, we have been troubled by the amount of tar which is thrown off the wheels into the chains, causing the former to wear very rapidly ; the tar also gets into the wheel bearings, causing them to run hot.
Our log sheet for the past week is as follows : Earnings, £105; tonnage, 240; mileage, 1,270; percentage of work done, 90; coke used, 15 tons; oil used (gear), 12 gallons and (cylinder) 5 gallons.—Yours faithfully, MOTOR-WAGON CARRIER:: The Future Three-tonner.
The Editor, THE COMMERCIAL MOTOR.
[1,210] Sir,—Now that steam-wagon builders arc again turning their attention to the development of the threeton wagon, it will be interesting to consider the advantages and disadvantages developed by the use of steam for this purpose. As in shipbuilding, the reduction cf the ratio between the total load and the load carried is
the main problem. Now, no successful three-ton steamer can be put on the road unless fitted with rubber tires, in order to compete with its stronger brother, the five-ton steam wagon, and its internal-combustion-engined rival. It is just this adoption of the rubber tires that militates against the advantages of steam. With steam, we have an increased tare weight: moreover, the drive being direct and not by means Of a clutch, a heavy strain is put on the rubber tires of the driving wheels of the threeton steamer in starting and stopping. All rubber-tire manufacturers, when guaranteeing, give the first consideration to the total moving load, and every hundredweight that can be saved in this direction without diminishing the load carried increases the guarantee given and lowers the running cost of the rubber-tire vehicle. A year on a rubber-tired steamer will see £150 worth of tires destroyed. Now, the petrol vehicle, with its tare weight some 30 cwt. or 40 cwt, lighter, and with its clutch-driven wheels, considerably increases the life of the tires—the most-expensive item in running a rubber-tired vehicle. Although the steam vehicle is silent and a fascinating suggestion. given two or three years, the heavy expenses of tire upkeep will put the internal-combustion vehicle far ahead of it in comparative running costs. The picking-up of sometimes-inferior water, the raising of steam, the continual attention to firing, water level, the pump, the injector, steam joints, etc., and last but not least the need of two men to drive, all point to the use of the internal-combustion engine in place of the coal-fired boiler and the steam engine for the development of the power necessary for the transport of goods on the highways. If it is agreed that the reduction of the ratio between the total moving load and the useful load is the base of the problem, then eventually the boiler and steam engine for this class of work must be discarded.—Yours T. C. AVELING.
Birmingham. 1We hope that some of our steam friends will answer Mr. Aveling's arguments and points.—E.]