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October, 1919 ing supported by a number of hori- yontal cylindrical floats, which renders it possible to use an ordinary type prime mover for moving the carriage on its wheels, the power necessary being relatively small. The immersion floats are so propor- tioned as to be able to support, when fully immersed, not only their own weight but also the weight of the carriage, which also is immersed to halt its height, together with the trough. The floats, when the carriage ig moved up and down, are displaced in a special waterbasin, corresponding to a lock-chamber, the water level in which is constant and whose depth in- creases with the height of travel of the ferryway. This height of travel is represented by the head of the sluice, and is equal to the difference in level between the upper edge of the floats and the lower edge of the trough. When raised from the middle position, in which the carriage is im- mersed to half its height, the iron carriage projects still further out of THE MARINE REVIEW the lock chamber or basin, gradually loses buoyancy, and thus increases in weight, this increase being no longer borne by. the. floats, but by the car- riage wheels and _ the driving ma- chinery. The reverse process takes place when the carriage is lowered. Additional stresses, which cannot be taken up by the floats, are caused by wind pressure on the trough, ferrying carriage and _ vessel transported. - Various other forces are set up and are supported by the driving engine. The firm of Gruen & Bilfinger has just completed an installation of this kind for the Neckar-Danube canal. It is found that 'with this System, as compared with the usual methods, working expenses are considerably re- duced. No water is necessary for working the lock beyond what is necessary to make up for ordinary losses. Also, fewer locks are re- quired and traffic is thereby facilitated. The dry lock, the trough and the float chambers are' made of ferroconcrete. --Zettschrift des Vereines deutscher Ingenieure. Drilling Square Holes in metal, shown in THE Martini tT : drill for making square holes Review for June, is worthy of | being better known. Its history, as recalled by the writer is as. follows: In the early eighties it was shown at an industrial exhibition held in Glas- gow, Scotland. It has been used gen- erally throughout England, France and Germany, and was quite exten- sively used by the Armstrong Gun Works, now -Whitworths, on the River Tyne. Some time during 1889, a tool salesman demonstrated and sold one to the J. Morton Poole Co., Wilmington, Del., which firm used it as a model for making other sizes. A few years later John Jack, fore- Man of the Harlan & Hollings- worth Co., now the Bethlehem Ship- building 'Corp., Wilmington, Del., improved the drill and also adapted it to milling the square ends of the Ports in many sizes of. marine en- gine cylinders built at the Harlan Plant. This same style of drill has also been used at the Washington Navy yard. The accompanying illustration is a drill actually used and kept in stock in the toolroom to be checked out and used by any machinist, the same as he would obtain and use a regular ee The aut the Taree uthor is instructor of apprentices at Plant of the Bethleh Shipbuilding Corp., Wilmington, De e Bethlehem p g (A Letter to the Editor of The Marine Review) WL WORK . DRILL" GUIDE DRILL, HOLDER AND GUIDE FOR MACHINING SQUARE HOLES 485 'Late Mave Patents Copies* of 'any of the following patents can be obtained by sending 15 cents in stamps to Siggers & Siggers, National Union building, Washington, by mentioning THe Marine Review: 1304865--Boat Sprincfi ld, Mo. 1304897--Davit, Canada. 1304961--Boat-bailing means, John Good, Brook- lyn;~ N.Y; : _ 1804984--Boat davit, James R. Irwin, San Fran- c'szo. construction, Ezra K. « Failor,: Thomas H. Marten, Toronto, 1°05228--Submarine boat, Conrad Regenhogen, - Kiel-Gaarden, and Hans Techel, Kiel, Germany, ass.ignos to Fred. Krupp Aktiengesellschaft Ger- maniawerft, Kiel-Gaarden, Germany. 1805340--Method and means for propelling craft ee fluid mediums, Lou's GQ. Bostedo, Log ngelcs. ; : * es lifeboat, Barney Goldman, New. ork. . 1505379--Reinforeed concrete ship and method of constructing same, Ralph R. Leffler, Chicago. 1305643--Boat launching and lowering Rodvrick Beaton, Pollockshields, Scotland. 1305700--Means for protecting ships from torpedoes, Julius Diners, New York. ° 1305877--Ship convoy submarine Carbau, Montevidio, Uruguay. 1306275--Reversible pontoon raft, Harold .B. -Perry and Humphrey W. Chambers, Barrow-in-Furness, Eng- land. 1305896--Boat or vessel, Samuel Golden, New York, assignor to Hullfin Boat Co., Inc., New York. in | Metal twist drill on ordinary machine work. Usually, it. as the practice, fo dal, a round hole nearly as large as the desired diameter of the finished square hole. This is not absolutely neces- sary but it is commendable as the strain on the drill spindle is heavy due to the fact that the driver springs as the drill "wobbles" in its guide. It is understood, of course, that the drill guide, must be rigidly fastened above the hole to be drilled. The lower illustration is a sectional view through the guide and drill. It.shows that in order to rotate, the three corners of the triangular drill must follow the outline of the square guide and, therefore, the similarly shaped cutting corners of the drill will travel through and cut the same shape. The illustration is self-explanatory. It shows the driver which should be long and flexible, the drill guide, drill and the piece of metal to be drilled, with a square. hole partly machined through it. This drill need not be confined to square holes, as holes of any number of sides, such as six or eight, may be drilled, provided, the drill and _ its guide have the proper shape. It is seen that the guide is in reality a leader for generating the shape desired. If the guide is hardened its life is increased. (Signed) A Edward Rhodes. | gear, defense, Mario