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-cumference, 103. | BEARINGS OF NAVAL ENGINES. By a Naval Expert Engineer, London. This very important subject does not up to the present ap- pear to have received the attention it deserves. In none of the numerous text-books, manuals, pocket-books, etc., on engineering which are published am I able to find out any specific information as to how to adjust a bearing properly, or what is the proper treat- ment to.administer. to one which has got damaged. Even the "Steam Manual," published by the admiralty as a vade mecum for the naval engineer is silent as to what ought to be done. The last naval maneuvers very forcibly demonstrated the importance of the subject, when several of our newest and most powerful battle- ships and cruisers. were temporarily hors de combat through hot bearings, and even Mr. Chamberlain was delayed in his journey to South Africa in the new cruiser Good Hope through the same cause. That the admiralty does not specify for large enough bear- ing surfaces has a very great deal to do with it, but T cannot help thinking that if what surface is provided be kept in the highest: state of efficiency the number of cases of failure on trials and dut- ing the ordinary work of a commission would be very much re- duced. But to start with, there is no method of adjusting brasses in the navy at.all, every engineer fitting his brasses according to his own ideas. In the large steamship companies there is a uni- form system made out by the superintendent engineer, with the result that hot bearings are almost unheard of. Ask a dozen en- gineers_in the navy how they adjust their brasses, and each one will tell you different. In the hope of, perhaps, giving a hint or two which may prove useful to your readers, and all of which are based on actual experience, I offer the following suggestions: _ First, with regard to.the-lubrication, it is almost needless. to say that the oil pipes must be kept clear and the worsteds kept clean. The latter should be occasionally washed in hot water and soda. The stokers who do the, greasing in the navy are not all thoroughly acquainted with the laws of syphoning,. and more-than, _ one hot bearing has come under my notice due to the fact that the level of the oil in the box.was below the lowest level of the worst-. ed down the pipe. The quantity of oil allowed by the admiralty is really sufficient if it is properly used; but, unfortunately, there are a large number of chief engineers of warships who have very © _ confused ideas as to 'their stores, and erroneously imagine that they gain favor by saving up a surplus. Olive oil is: undoubtedly the best lubricant for bearings, but, as the quantity supplied is hardly sufficient, a capital mixture can be made of two olive to © one Crane. Having attended 'to the lubrication, the next point demanding Bearings aré usually adjusted in » three different ways in the 'navy. The first is by "swinging," by. < which is meant that, after-the- bearing has been adjusted to-the ~ _ proposed position, the rod is taken in the hand and swung through attention is the bearing itself. an arc to test its tightness. This, naturally, is only applicable to b small, light machinery. The second. method is by flogging up the . Nuts on.the bolts till the brasses grip the journal and then slack- ~-ing. back a given amount, calculated by the number of threads per inch on the bolt, the diameter from corner to corner of the nut, and the amount that the chosen corner has been eased back from the "hard-up mark." Liners are then inserted. The third is by inserting between the brass and the journal a piece, or several pieces, of lead wire, tightening up.to the former position and.then removing 'the wire, and by'its thickness, gauging 'the amount of. clearance between the journal and brasses. FI will deal' with each of these methods in turn. Swinging a rod is the best metliod Tor light machinery, which . catty bé comfortably managed by one man, using only his: right -- hand. A very little experience will teach how much to tighten | et ine t should never 'be forgotten to put the check nuts on proves nothing as to the bearing surface between the brasses and journal.. An examination of the brasses may prove. that they . are only bearing on one corner; so to find out what is really the State of affairs under working conditions, a lead should be laid « along the bottom brass, aad two--if it be small--round the cir- cum The flatness of the lead will show where the bear- ie. surface lies, and this must be filed or scraped away till the» lead comes out'uniformly flattened. a Wee. » Now, with regard to the second method, namely, tightening up and slacking back, which is much in vogue amongst the older . hiaval engineers, there are several possible sources of error. "In~ the first place, a powerful man with a heavy hammer can spring a long bolt and perhaps tighten up from a quarter to half an inch _ more than a weaker man-with a light hammer. Not infrequently, _ the brasses themselves get sprung in at the "horns" and bulge _ Out at the crown. Having tightened up to this movable "hard-up _ .mark," the nut is slackened back, but no allowance is made for the w _ the be ho knowledge can be obtained by this method as to the amount ar. of the threads and consequent slackness of the nut, on t, But my final objection is that, as in the case of swinging, of the bearing; it may be on a couple of small spots in the horns, Which, when they have been scraped down, leave the brass a blank, unless the process of riddling with red lead and oil be Tesorted to, which is a very long and trying process, and not always accurate. The most accurate and, to my mind, only scien- _ tific method, is lead wire and a wire gauge. 1 t manner, all that is required is to insert the lead wire, one piece To adjust in this along the bottom and two or three round according to size of journal, tighten up hard on the liners, slack back, take out the MARINE REVIEW AND MARINE RECORD. iA ad Scndae hentai a efore. swinging, as a 'rod which swings quite easily, will often | »- be found ,too stiff' to move by hand when the check nuts are . tightened down. Granted that the rod swings satisfactorily, this 27 wire, and put'it into the slots in the wire gauge. It'can be accur- ately measured to the thousandth of an inch by this method, and the record kept conveniently in a pocket-book, instead of filling the office with old leads, which get damaged; and all bearings can be adjusted to the same amount of clearances. Now, with regard to the wire gauge, we will take the legal standard gauge, as this is now most generally adopted, although any engineer's pocket-book will give the equivalents in the other gauges. For the engines of a battleship or large cruiser, 24 L.S.G. will be a good adjustment for all the main bearings, 24 L.S.G. for the crank pin brasses, and 26 L.S.G. for the crosshead if of white metal, or 24 L.S.G. if of brass. Nothing should warm up,.at that, and no worry need be caused by a_ sud- den gréat "increase of speed, although the engines may not be perfectly silent at very low speeds, But you cannot adjust bear- ings so that the engines 'shall run:cool and quietly at every speed, and safety at high powers is perhaps better than a slight bump when running slow. For the engines of smaller cruisers making from.120 to 180 revolutions per minute 27 L.S:G. for main and crank pin brasses, and 28 L.S.G. for crossheads will be found ...Satisfactory...But itis always better to err on the slack side, because it saves the use of sea water, which not only spoils any journal, but decays the white metal through setting up galvanic action. The engines of destroyers can be swung, but if leads are required a 30 L.S.G. for main bearings and cranks and cross- heads will run without trouble. Ya With regard to the thrusts, if they be of the now almost universal horseshoe type, they can easily be set with feelers; and I would here recommend all who have the adjusting of engines to purchase'a wire gauge and a set of feelers, the cost of which ~ will not' ammount to-more: than ~"five~or" six shillings. First;~the engines have to be got aft to the required position. This is easily done by slacking off the collars, and turning the engines astern by the turning engine. Should there be no marks to indicate when the.-engines are central, a very easy way is to try by feelers the clearances between the forward and aft sides of the link blocks and the fork end of the slide rod, that is, provided the engines are fitted with Stephenson's double bar link gear, which nearly all 'modern ships have. This is generally where the wearing forward ofthe shaft first exhibits itself, and I have always found if the 'valve gear is true the cranks and crossheads are not far out. Having got the engines central, the next. thing.is to tighten up the thrust collars, so that a very thin feeler can be inserted all round, which will prove that the collar and shoe are parallel, and that the bearing is taking all over. To go into the adjustments of all the other bearing surfaces would make this article too long, but it is hoped that enough has been said to show the importance of the subject. Carelessness and neglect are sure to appear, and gémerally at the most inconyenient-time.--Too- much care: to- the exact measurement of all adjustménts cannot be paid. BELLEVILLE COMING INTO ITS OWN. Sentiment in reference to the Belleville boiler in England has undergone so complete a change as to amount to revolution. No scorn at-one time was too withering for this type of boiler; no praise. at present can be*too high. The English journals have been, unanimous in their approval of the performances of this poijler.. In fact they couldn't be otherwise and be fair. The rec- ord of the' Spartiate put an effectual quietus upon the anvil chorus. "Concerning recent performances the London Telegraph ' "Those of us who thought that the Belleville boiler had been "somewhat hastily. condemned by the boiler commission, and as 'hastily abandoned by the admiralty, in deference to a certain amount of popular clamor raised by Sir William Allan and others, are beginning to find our justification. We shall find it more fully as time goes on. The Belleville may or may not be the best water-tube. boiler; I hold no brief for it, and nothing but practical experience can show its merits or demerits in compari- 'son' with other water-tube boilers. But that the cylindrical boiler is as dead. as a door nail is hardly open. to question, and the ' sooner the admiralty recognizes the fact and makes the neces- sary adjustments in the boilers of some of the ships now under construction the better. The present Victoria and Albert is a standing testimony to the merits of the Belleville when. it is properly understood. So is the Spartiate, which traveled 25,000 miles without a defect in her boilers of any kind, though her engines once gave a little trouble. During the recent maneuvers -.ghe- steamed for- ninety-six- hours at. 18 -knots--because her en- gineers and stokers knew their business, though they. had been changed three times in five months--and the maneuvers are really the best evidence of the merits of the Belleville. There was no break-down among the Belleville-boilered ships of the X fleet, and two of the three ships of the squadron which were not fitted with Belleville boilers were the two that dropped behind--the Cesar and the Illustrious. True that they were not originally designed to steam as fast as the others, but the fact that the eight Belleville-boilered ships did so well says a great deal for the boilers. So do the performances of the Spartiate and Europa and of the Good Hope, which increased her speed from 9 to 19 knots in under ten minutes. The Belleville boiler wants a lot of keeping clean, but if it is thoroughly understood and properly treated it also wants a lot of beating," - .Mr. J. M. Martin has resigned his position as distfict sales agent at the Philadelphia office of the Nernst. Lamp' Co., and _ Mr. A. E. Baker has been appointed as his successor... .