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. Equipment Used Afloat and Ashore Rotary Air Grinder—Tensionmeter—Airplane Hoist Control—Oil Ring Type Marine Bear- ings—Portable Crane—Dustless Sander—Electrolysis Eliminator—Marine Signal Device NEW type of portable rotary A air grinder, produced by the Cleveland Pneumatic Tool Co., Cleve- land, is shown below. This grinder is made in several sizes and may be used for any general grinding where a portable tool can be used to advan- tage. The new Cleco rotary grinder has a single rotor which is concentric with the arbor, insuring a perfect balance at all speeds. The rotor is provided with four longitudinal New Type Portable Air Grinder slots to accommodate four separate blades which are in turn forced out- ward to the wall of a stationary eylinder which is set eccentric to the axis of the rotor. As one blade of the set is always exposed to the air current a constant rotation is estab- lished. The arbor to which the ro- tor unit is attached is rigid and made of selected steel. The governor is a detachable unit and when in op- eration controls and governs the amount of compressed air used. An oil reservoir in the rear end of the grinder body, is filled with oil au- tomatically delivered to the rotor, the flow of lubrication being con- trolled by the governor. Ease and Accuracy Mark Use of Tensionmeter HE tensionmeter shown in the ac- i aa illustration quickly and accurately gives the tension on wires, cables and lines. Its heavy aluminum case and all exposed parts are chrom- ium plated or made of stainless steel. It weighs 14 pounds and measures two and one-half feet overall. The standard model will test all wires. and ropes up to one inch in diameter and has a ten- sion capacity of 16,000 pounds. Larger capacity meters and meters for special shaped cables are also available. Hills- McCanna Co., 2551 Nelson street, Chi- cago, are the manufacturers. Docks and ship riggers use the ten- sionmeter for measuring cable tensions and for weighing. Equalizing the load on multiple cables is another important use for the instrument. This instru- ment replaces the dynamometer and provides a more accurate device for testing wires and cables without cut: ting or marring. For operation, the tensionmeter is simply hooked on to the wire in any position and the center bearing tight- ened, which deflects the cable. A cor- rect reading is given at once. The whole operation takes less than a minute. The reading is taken directly from the scale in pounds; there are no calcula- tions or temperature corrections to make. There are no liquids, glass or loose. parts to cause trouble. No wrenches or tools are required in its operation, enabling workmen, dressed for severe cold weather, to use the meter without trouble. Airplane Hoist Control On U.S. S. Pennsylvania NEW and interesting application Act shipboard installations on naval vessels is that for handling airplanes through motor driven hydraulically operated speed gears. For such an ap- plication, the motor, which is usually of the constant speed, shunt wound type, requires a suitable starting equip- ment. As the complete electrical equip- ment is installed in an exposed location, the. motors and controllers are of the waterproof type. A typical installation is that recent- ly effected on the battleship Pennsyt- VANIA and the control for this appli- cation is shown in the accompanying Hills-McCanna Tensionmeter Shown in Operation 38 MARINE REVIEwW——J uly, 1931 halftone below. This design of controller is used with a 35 horsepower 115 volt D. C. constant speed motor. The panel is constructed of asbestos illustration which appears lumber with a sub-panel suporting the necessary resistance units located for easy access. On the main panel are mounted a double pole, unfused line knife switch, an adjustable overload Airplane Hoist Control relay, two line series relay type accelerating contac- tors, navy.test link and necessary ter- minals. Operation is obtained from a remote 3 wire control waterproof pushbutton station, the controller being designed for low voltage protection. The control- ler conforms to United States navy re- quirements for class A shock, and the contactors, relays, ete., are so designed as to be not effected by pitch or roll of the vessel up to an angle of 45 degrees. from normal. All parts liable to corro- sion due to salt atmosphere are suit- ably protected by zine plating or sher- Inc., Mil- ardizing. Cutler-Hammer, waukee, are the manufacturers. Oil Ring Type Marine Bearings Perfected ECENTLY a new type of bearing for marine service has been de- veloped by the Westinghouse Elec. & Mfg. Co., East Pittsburgh, which re- contactor switches.