Synthetic Rubber Hose Synthetic rubber hose has a seamless synthetic rubber inner tube covered with layers of cotton and wire braid, and an outer layer of rubber impregnated cotton braid. The hose is provided in low-, medium-, and high-pressure types. Synthetic rubber hose (if rubber-covered) is identified by the indicator stripe and markings that are stencilled along the length of the hose. The indicator stripe (also called the lay line because of its use in determining the straightness or lie of a hose) is a series of dots or dashes. The markings (letters and numerals) contain the military specification, the hose size, the cure date, and the manufacturer’s federal supply code number. This information is repeated at intervals of 9 inches. Refer to figure 5-2. Size is indicated by a dash followed by a number (referred to as a dash number). The dash number does not denote the inside or outside diameter of the hose. It refers to the equivalent outside diameter of rigid tube size in sixteenths (1/16) of an inch. A dash 8 (-8) mates to a number 8 rigid tube, which has an outside diameter of one-half inch (8/16). The inside of the hose will not be one-half inch, but slightly smaller to allow for tube thickness. The cure date is provided for age control. It is indicated by the quarter of the year and year. The year is divided into four quarters. 1st quarter — January, February, March 2d quarter — April, May, June 3d quarter — July, August, September 4th quarter — October, November, December The cure date is also marked on bulk hose containers in accordance with Military Standard 129 (MIL-STD-129). Synthetic rubber hose (if wire-braid covered) is identified by bands wrapped around the hose at the ends and at intervals along the length of the hose. Each band is marked with the same information (fig.5-2). are its operating temperature range, its chemical inertness to all fluids normally used in hydraulic and engine lubrication systems, and its long life. At this time, only medium-pressure and high-pressure types are available. These are complete assemblies with factory-installed end fittings. The fittings may be either the detachable type or the swaged type. When failures occur, replacement must be made on a complete assembly basis. Teflon® hose is identified by metal bands or pliable plastic bands at the ends and at 3-foot intervals. These bands contain the hose military specification number, size indicated by a dash (-) and a number, operating pressure, and the manufacturer’s federal supply code number. Refer to figure 5-2. HOSE ASSEMBLY HARDWARE Hose fittings are designed and constructed in accordance with military specifications and military standard drawings for particular hose configurations and operating pressures. Fittings designated by a military standard drawing number have a particular dash number to indicate size. The fitting dash number does not designate a size in the same manner as a hose dash number. The fitting dash number corresponds to the dash number of the hose so that both will match at the critical dimensions to form a hose assembly. Materials used in the construction of fittings vary according to the application. Materials include aluminum, carbon steel, and corrosion-resistant steel. Fittings that qualify under one military document may be produced by several manufacturers. Two methods or styles are used to secure the hose fitting on to the hose. They are the reusable and swage or crimp style. Reusable Style Teflon® Hose The preferred reusable style has modified internal threads in the socket to grip the hose properly. The The Teflon® hose is made up of a tetrafluoro- fitting can be disassembled from a hose assembly and ethylene resin, which is processed and extruded into reused on another hose, provided it passes an tube shape to a desired size. It is covered with inspection for defects. Reusable style fittings are stainless steel wire, which is braided over the tube for authorized replacement fittings for replacement hose strength and protection.   The advantages of this hose assemblies. 5-2