creased. This, with the change in axle-plates, would not add materially to the weight of the system. (3) Transoms, wherever practicable, be attached to flasks by rivets, as in case of the lunette. Trail handles also might be riveted to flasks. (4) Front end of elevating-screw guide-bar, instead of being suspended from upper front transom, be centered on an assembling bolt, with separator passing through cheeks; heavier screws be placed in spline in large gear-wheel. (5) All bolts be furnished with locking-nuts or nut-locks. (6) The trail handspike be strengthened by a metal band near the swell and a ferrule at the small end. (7) Better fastenings be provided for lid of tool-box; also attachments for securing to carriage 1 long sponge and rammer, 1 short ram. mer, and 1 sponge-bucket; the short rammer and the prolonge to be carried on the limber. (8) Spring brakes, for recoil checks, similar to those used during most of the trial, to be applied. (9) If axle-seats are required by the artillery service, some more suitable than any so far submitted with the different carriages must be designed. (10) Steel made by the "open-hearth" process to be used for the flasks and transoms. J. MCALLISTER, Colonel of Ordnance, President of the Board. A. MORDECAI, Lieutenant-Colonel of Ordnance. EXPLANATORY REMARKS. BY LIEUTENANT-COLONEL BUFFINGTON. I. "The form of axle-plates and number of rivets placed in them" have been shown by the severe tests to which they have been subjected, in two carriages, to be adequate for the work. The first axle with plates so riveted is still at Sandy Hook, as perfect as when fabricated, although it has been used constantly after the 500-round test given it. The plates of this axle are apparently 3" thick-edges show so-but the planing to true the surfaces of contact, after the crude hand-work of bending around a former, reduced this thickness in places to less than . This record is not departed from in the present carriage, although there was some bending at the extreme ends of the axle-plates in front and one rivet was broken. Careful measurement shows no bending of the plates in rear of the axle, and there is no evidence of weakness either in plates or rivets. The cause of the bending, attributed to the striking of the brake-rods on the brake eye straps, has escaped the Board's attention. The jaws of the brake eye straps not bearing on the plates (underneath) in front and (on top) in rear at the same time, the whole work-twice as much as should have been-was thrown on the front side of axle, until by the bending of the plate ends in front the "play" of the jaws was taken up and the rear side made to perform its share; the bending then ceased. The foreman departed from his instructions in putting on these straps. The one rivet broken may have been defective, or imperfection combined with the shearing effect of two bending plates, or the latter alone may have broken it. The axle-plates of carriage, "described in report of the Chief of Ordnance for 1884, page 539," depart from correct mechanical principle and from the model, which successfully endured the test of 500 rounds and much subsequent firing, as above related. II. The upper and lower front transoms in shape conform to the requirements of the construction. Moisture can not be "excluded" from any part of a carriage constantly exposed to the weather. The lower front transom and part of carriage under it can be painted and thus protected like the other parts from rust, and the paint can be renewed when necessary by removing the transom, which is bolted to the cheeks. The amount of dust or other matter that may collect in the space referred to can be little in amount, and have no practical bearing on the life or service of the carriage. A portion, however, from the rear of the lower front transom could be cut out with profit to the weight, to render said space accessible, and this will be done. The transoms are thick enough; they could be made still thinner. III. Only the front lower transom and parts pertaining to the elevating apparatus will be bolted in the new carriages. IV. The additional bolts uniting carriage-body to the axle-plates were added in this carriage to insure the strength needed-the carriage-body flange being but 4-inch metal. This is the raison d'être (otherwise not required at all-that is, simply as a transom it is superfluous) of the lower front transom, and for the same reason the rear front transom is also bolted to the axle plates. V. The manner of attaching the front end of the elevating screw guiding bar is preferable to the one recommended in several particulars. Holes in the flasks of a carriage are elements of weakness, and no more should be made than absolutely necessary. To substitute an "assembling bolt" would cause the boring of two unnecessary holes through the flasks in close proximity to others. As there is but little stress où this bar, the cause of the breaking of one attachment must be due to initial fracture in putting on the nut-screwed up too tight—or the vibration set up by firing, or both combined. The whole elevating apparatus was taken from the Watervliet carriage (Report of Chief of Ordnance 1885, appendix 57), but it was so badly constructed the gears were recut. The spline was without attachment of any kind to hold it in place, and a small screw was added for that purpose. The cause of the occasional hardworking was found, at the armory, to be the turning of the irregular "collar" on the shaft outside of the cheek. The construction has been remodeled to eliminate the defects. VI. A locking nut has been found that promises efficiency. VII. The trail handspike on this carriage was taken from the Watervliet carriage referred to above. An effort will be made to improve it. VIII. A hasp and turnbuckle to fasten the lid of tool-box to the side of transom will be substituted for the hook and staple fastening on top, which the spring of the trail unfastens. IX. The carriage being experimental "provision for carrying implements" was omitted to be provided after establishing the suitability of carriage for the service. X. The cap-squares and keys were taken from the Watervliet carriage referred to above, and a better fastening will be substituted. XI. To the time of fracture the defects shown in recoil brakes-throwing off the wheel and unlocking of the levers of attaching device-were matters easily corrected. The flange of the brake-shoe for overlapping the tire should be as short as possible to facilitate the placing of brake on the wheel; the longer this flange the nearer the vertical must the brake be raised to throw it on. The correction lies simply in lengthening the flange until the brake can not be thrown off. "Brakes unlocked" means the tangs on ends of lever handles out from their seats between the springs-the brakes were not unlocked from the carriage-the remedy for which is increased length of tang. The connection of the brake to the axle "was not through an eccentric." It is not eccentric but concentric and positive. The adaptability of the brake "in other respects" than strength is, therefore, something more than "immaterial." The very essential feature and one to which the Ordnance Board has attached importance (Report of Chief of Ordnance for 1883, page 315), viz, that of unlocking, when in use on the march, for braking down hill, was successfully shown, and this feature can be combined with any form of brake. The flat springs have been shown to be unsuited as fabricated for the work, but the principle-no initial tension and the expansion not limited by an unyielding shoulder-is the correct one, what is required for the carriage and what will be preserved if possible. For the twenty-five new carriages under construction, as there will be no time for further experiment with brakes, the spiral spring brake as designed by me for the first experimental carriage will be used, because this one or its equivalent has been used in all the tests. But it is considered no better than a rigid brake, and the first test, in which both spring and rigid brakes were used, would have so shown had the latter been made as desired. XII. Axle seats of any kind other than wooden ones, fitted in immediate contact with the axle, were not approved of, but the Ordnance Board desired seats. Its (then) president was consulted as to kind, and they were made for the first carriage (spring seats and of medium height), to conform to his wishes. The transportation to Sandy Hook and trial of this (first) carriage made it quite evident that they were unsuited. The same seats were put on the second carriage with a different attachment to the cheeks of the carriage. This, on one side, as with the first carriage, was broken off during transportation to Sandy Hook, and the other side, showing no efficiency, was soon removed. The criticism applies to the seats unattached to the carriage body. It was not in tended they should be so used. It was stated to the Ordnance Board before the trial that "no stock was taken" in the seats on this carriage, but their presence would serve two purposes, viz, show whether any seats of this character would suit and the manner of attaching the brakes when on the march to any seats. If a cannoneer can ride on the limber-box without support for his back he can so ride on an axle seat; backs were therefore not provided. A step or foot rest is considered a useless incumbrance, but for the height and character of the seat one had to be put on. For the new carriages the seats will be the simplest possible, without springs and backs and low enough to make steps unnecessary. Horse batteries do not require them and they will be made so they can be readily removed. XIII. When open hearth steel can be furnished possessing the qualities of the steel used, and when it is demonstrated that Bessemer steel can not be made sufficiently uniform for what the constructor of the carriage wanted, it will be time enough to discuss the relative merits of the two. The steel used was tested on the Watertown arsenal testing machine, and on inquiry as to comparison with like metal tested the following reply was made: "Colonel Buffington's inch steel plate gave the following results, the average of four specimens: E. L., 51,640 pounds per square inch; T. S., 70,750 pounds per square inch; cont., 45.3 per cent.; elong., apart from ruptured section, about 18 per cent. "Our inch plate for riveted joints gave "E. L., 40,159 pounds per square inch; T. S., 60,295 pounds per square inch; cont., 53.5 per cent.; elong. in 10 inches, 23.6 per cent., which are fully up to the average tests. Colonel Buffington's tests are unusually high. I don't recall any tests that combine so good elongation and contraction with so high a tensile strength and elastic limit. "Respectfully, "J. E. HOWARD." The cracks in the upper front transom were the result of too much heating and forging. It was used for the first carriage and reforged for the second. Though cracked, the test showed it to be strong enough. 8868 ORD-7 Above. Fired into sand butt to test carriage. Hook, N. J., from November 11 to November 24, 1886. Special remarks about each fire, such as effect on piece, sound of projectile in flight, scattering of fragments, etc. Mounted on Colonel Buffington's carriage as received November 3, 1886. The gun was received back from West Point Foundry November 9, 1886, where it had been fired 29 rounds. An incipient crack in right angle of upper front transom was detected before firing. Front and rear hooks of left seat were off when carriage was received. The gun was fired from board-walk platform until round 2215, and bow-spring brake furnished with carriage used until round 1994. Left front assembling bolt through axle plate broke and firing stopped that it might be replaced. Before firing round 1947 a slight crack in right edge of front transom was noticed. Hooks of right axle seat were jarred loose. Rear hook right seat loosened and front one partially so. 20 by 40 feet), for accuracy and to test Mean horizontal deviation from center of impact, 2'.91. Mean deviation from center of impact, 5'.28. 10.75 38.27 73.28 17.63 17.63 11.64 11.64 27.52+8=3.44 73.28-8-9.16 35.26÷8-4.41 23.28÷8=2.91 Both brakes jumped off. Left brake jumped off. Both brakes unlocked. Left brake jumped off. Both brakes unlocked. Brakes secured to axle by an eccentric fastening; this "unlocked." Both brakes unlocked. |