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Automatic Arc Welder Has Variable Speed Motor An automatic are welder for weld- ing the head in small tanks, such as range boilers, oil and gas tanks, ete., utilizing the electronic tornado principle is illustrated in the accom- panying cut. This piece of new equipment has been produced by the Lincoln Electric Co., Cleveland. This machine is characterized by its extreme simplicity. The holding fixture consists of a rotating table driven by a small variable speed mo- Automatic Arc Welder tor and a vertical support carrying a fixed steady rest and the welding head. The electronic tornado welding head is flexibly mounted so that the length of the arc is at all times under the control of the operator. The chief advantages claimed for this machine are high-welding speeds and smooth uniform welding speeds. In making an edge weld as illus- trated in the photograph, no addi- tional filler metal is used. The heat of the carbon arc fuses the edges of the cylinder shell with the flange of the dished head making a leak-proof joint. Welding speeds of 100 to 150 lineal feet per hour are claimed for this machine. The framework of the machine itself is constructed en- tirely from welded steel. This type of construction has been used for a number of years by the company in their standard line of motors and welders and was followed in bringing out a new line. This machine is but one of the many applications of the electronic tornado principle de- veloped by the Lincoln research laboratories and announced several months ago. Wide Charting Range in Recording Thermometer A recording thermometer capable of charting temperatures from minus 40 to plus 750 degrees Fahr. has been perfected by the Moto Meter Gauge & Equipment Corp. of Long Island City, N. Y. The instrument, developed after several years of ex- perimentation, is known as the Model 1000 Motoco recording thermometer. In design, the instrument consists of a dust, fume and moisture proof housing which encloses the working parts. The element is comprised of a bulb, capillary tube and Bourdon tube, filled solidly with a _ special liquid which has an equal coefficient of expansion over the entire scale range. When the bulb is subjected to heat or cold, the liquid content therein expands or contracts and this action is transmitted through the capillary tubing to the Bourdon tube, causing the latter to wind or unwind and move a pen across the face of a chart actuated by a 24 or a 7-hour clock mechanism. The ratio between the pressure of the liquid and the movement of the pen is one-to-one so that levers, hair springs, screws, gears and other deli- cate parts are eliminated. A com- pensating spring takes up any differ- ence between the bulb and room tem- perature and automatically resets the pen at the point on the chart corre- sponding with the bulb temperature. New Recording Thermometer Charts Temperature from 40 Minus to 750 De- grees Plus Fahr. MARINE REviEw—March, 1932 Adjustable Circular Saw Is Motor Driven Suitable for use in the marine field in operations of cutting seam- less steel tubing and forged metal where speed and a smooth cut are desirable, a circular saw has been produced by the De-Walt Products Corp., Leola, Pa. The device as shown in: the ac- companying illustration consists of a circular 12-inch hollow ground metal cutting saw driven by a 5-horsepow- er overhead direct drive. The saw is Circular Saw for Hard Steel adjustable to any angle and will handle tubing up to 3 inches in diam- eter and 4%-inch wall thickness. Op- erating speed is 3600 revolutions per minute. The saw blade is said to give 3 to 4 days continuous service in cutting molybdenum steel before resharpen- ing is necessary. Hight to 10 days is the service time claimed for the saw when low carbon steel is being cut. For holding the work an air grip vise has been incorporated: in the ma- chine. This vise operates on 30 to 150 pound air pressure and the jaws are adjustable to handle tubing up to 3 inches in diameter. The cutter first was developed to meet the needs of the airplane in- dustry in making the many angle cuts necessary in fuselage construc- tion. This material was mainly molybdenum steel, one of the hardest alloy steels. Two Dutch tugs in 166 days traveled 13,500 miles, from England to New Zealand, towing a floating dry dock which, because of its size, was launched in three sections. This is believed the longest tow on record. 41.