=The gun carriage= for the 3-inch gun Model 1905 is of the type known as the long-recoil, in which the gun is permitted a sufficient length of recoil (about 45 inches) upon the carriage to render the latter stationary under firing stresses. The gun is mounted upon a cradle which forms a housing for the recoil controlling parts. The cradle rests upon the rocker and has a small traversing motion of 70 mils on each side of the axis of the carriage. The rocker is journaled upon the axle and its rear end is supported by the elevating mechanism, which is seated in the trail. The principal parts of the carriage are the wheels, axle, trail and elevating mechanism forming the lower carriage, the cradle and recoil-controlling parts constituting the upper carriage, and the rocker and traversing mechanism intermediate between the two. In addition there are provided shields, ammunition carriers, the road brake, and the axle seats. =The Wheels and the Axle.= The wheels are a modified form of the Archibald pattern, 56 inches in diameter, with 3-inch tires. The axle is hollow and forged from a single piece of steel. The wheels are held on by the wheel fastenings. =Trail.=—The trail consists of two steel flasks of channel section with the flanges turned inward, tied together by transoms and plates to form the sight and the tool boxes. Attached to the trail are the trail spade, float trail handspike, trail handles and the lunette. =Elevating Gear.=—The elevating gear is of double-screw type and consists of an inner and outer elevating screw, an elevating-gear bracket, an elevating bevel gear, two elevating bevel pinions, and two elevating crank shafts. The inner elevating screw is a steel screw, threaded with a right-hand thread. It is attached at its upper end by the elevating pin to the rear end of the rocker. The outer elevating screw is of bronze and is threaded on the exterior with a right-hand thread to take the inner elevating screw. On the exterior are also cut two longitudinal keyways, in which the keys of the bevel gear work. =Traversing Mechanism.=—The traversing mechanism consists of a shaft, called the traversing shaft, mounted in bearings in the traversing-gear case, and a traversing nut moving longitudinally on the shaft, but restrained from turning with it by its bearings in the gear case. A cylindrical lug on top of the nut fits in a hole in a bronze traversing link, the right end of which is pivoted by the traversing-link pivot to the traversing lug on the underside of the cradle. This pivot is secured to the cradle-traversing lug by a nut and split pin. The left bearing of the traversing shaft is split for the purpose of assembling and rests between two collars on the shaft. The bearing, with the shaft in place, is slipped into its seat in the gear case, where it is held in position by two pins. [Illustration: _TRAVERSING GEAR, VERTICAL SECTION_] [Illustration: _Elevating Gear_ _Half Elevation and Half Section_]