34 



HARDWOOD RECORD 



November 25, 1918 



taxes" to be collected in 1019. Tbls Is clone by the issue of these tax 

 anticipations. 



To avoid possible high interest rates next March when taxes tall due. 

 all corporations and individuals liable for federal tax payments should 

 purchase these tax anticipation certiflcatcs. It is a patriotic duty and it 

 is good business. 



Wornout Railroad Ties as Fuel 



After a railroad tie has served its day in tlie tracls it is not wholly use- 

 less. Its principal damage may consist of deep notches worn by the 

 rails, or it may be split or partly crushed, or partial decay may have 

 rendered it unsafe as a tie. It still has a value as fuel. Some railroads 

 use ties as kindling wood for the locomotives in round houses. Railroad 

 worliers provide their winter fuel from the heaps of rejected ties, and 

 farmers who live near the tracks often use many ties in the same way. 

 The ties thrown out of tracks each year exceed 100,000,000, equivalent 

 to 5,000,000 cords of wood. This is an important resource in time of 

 fuel shortage. 



Selecting Oil for Bearings 



The pressure which any bearing will withstand without seizing depends 

 largely on the temperature, velocity of rubbing, and quality and descrip- 

 tion of the lubricant used. 



The lower the temperature the greater the permissible pressure, and the 

 higher the velocity of rubbing the less the permissible pressure. This is 

 due to the fact that oils become thinner and more free-flowing as higher 

 temperatures are reached, and consequently more easily squeezed out of 

 the bearing. A very light oil is liable to be squeezed out with a pressure 

 as low as from 50 to 60 pounds per square inch, whilst a heavy cylinder 

 oil will possibly stand a pressure of 1,000 pounds per square inch. The 

 maximum pressure that commercial oils will withstanding varies from 500 

 to 1.000 pounds per square inch where the load is steady. It is not 

 advisable that more than two-thirds suih loads should be applied at slow 

 speeds, and this should be reduced proportionately as the speed increases. 

 The advantage of selecting suitable oil is therefore apparent. 



Wood for Violin Bows Is Scarce 



The violin bow is small and does not require much wood in the mak- 

 ing, but that little is now hard to get. Wood for the bow must possess 

 certain qualities in a high degree. Many woods have been tried and a 

 number are in use, but the one now most wanted and the hardest to get 

 is a species belonging to the numerous rosewood family, and is a native 

 of tropical Africa, chiefly on the west coast in Senegal and_ Sierra Leone. 

 It is known in the market by so many names that some persons suppose 

 there are several distinct woods. Among the names arc ebony. Senegal 

 ebony, purple ebony, brazil wood, grendilla, dialamban, congoholz, amerim- 

 non, dalbergian, and African blackwood. Some of these are names 

 belonging to other woods, and some of the names are misleading. For 

 Instance, It is called ebony, but it is not even in the ebony family. It 

 is more nearly related to locust. Botanists call it Dalhcrijia melanoxylon, 

 and its relation to the rosewood of comiuerce is very close. 



It is scarce now because it was formerly olitained through Germany, 

 and of course the Germans are no longer exploiting African resources. 

 It is so heavy that perfectly dry wood sinks in water. It is hard as ebony, 

 which is usually classed as the hardest wood, and it is as black as ebony, 

 or blacker. The wood is exceedingly dense; the pores are filled with resin, 

 and the medullary rays are so small that they are invisible without a 

 microscope. One inch may contain 250 of the rays. It is highly elastic, 

 and that is one of the chief qualities demanded by the violin bow maker. 

 .\nother is weight, and still another is strength. 



Persons in this country who are interested in violin making are taking 

 steps to secure this wood without dependance upon Germany. There is 

 likewise a movement to make in this country such violins as we need and 

 not import them from Germany and .\ustria, as was done before the war. 



U. S. Commerce with the Dominican Republic 



During the year 1917 imports from the United States into the Dominican 

 Republic are shown in the following figures recently published by the 

 Dominican customs receivership: 



Agricultural machinery .$ 109,495 



Vehicles l*'^'*^! 



Railway and train cars 177,627 



Musical instruments 26,373 



Lumber 48,498 



Furniture 103,822 



Total <if all kinds for United States. . . .' $14,320,351 



During the same period the exports from the I>ominican Republic to 

 the United States were : 



DJewoods .f 122, 156 



Lignum vitae 49,111 



Mahogany 4,302 



Facts About Flywheels 



The speed at which a flywheel may be safely run depends upon the 

 material of which it is constructed, upon its design and upon the con- 

 dltlons under which it is used. 



For any given material, the strength to resist centrifugal force does 

 not depend upon the quantity of material in the rim, but only upon the 

 tensile strength of that material, and for any given material in a flywheel- 

 rlm there is a definite rimspeed or velocity that cannot be safely exceeded. 



It is current practice to operate flywheels at a rimspeed of about a 

 mile a minute. The limit of safety, however, varies with the material of 

 which the wheel is built, and in sectional wheels also with the type of 

 rim-joint employed. 



Wood is a better material for flywheel-rlms than cast-iron, and steel 

 is better still. The best materials of all for this purpose are boiler- 

 plate or steel-wire, and both of these have been used in the construction 

 of special wheels. With wood, boiler-plate, or steel-wire rims, the hub 

 and arms are generally made of cast-iron. 



Wooden wheels may be run at a considerably higher speed than cast- 

 iron wheels. For example, a well-constructed maple wheel made of seg- 

 ments with staggered joints may be run at a rimspeed of 1.75 miles per 

 minute (approximately 52 per cent higher speed than a cast-iron wheel 

 with a solid rim), provided the rim is laminated so that 50 per cent of 

 the material must break to part the rim. It would be unsafe, however, 

 to run some wooden wheels at a speed ot a mile a minute, owing to their 

 imperfect construction. 



Well-constructed steel wheels may be run with ample margin tor safety 

 at a rimspeed of 1.90 miles per miuute. The cost of such steel flywheels 

 is so great, however, as to preclude their general adoption. 



The usual flywheel is made of cast-iron. This Is on account of Its 

 facility of machining. Provided that the wheel is properly designed ; that 

 the best grade of cast-iron Is used ; that the construction is first-class ; 

 that the conditions of service are suited to the limitations of the material, 

 and that the engine on which the wheel is used is equipped with proper 

 over-speed safety devices which are kept In working order, cast-iron may 

 he regarded as satisfactory for the purpose. 



Where a flywheel serves also as a belt-wheel and it is desirable to have 

 more power than the belt can transmit at normal speed, there is a great 

 temptation to increase the speed. This is because the power transmitted 

 by a belt is proportional to its width and speed, and any increase in speed, 

 up to the point where the belt begins to slip badly, means that much more 

 power transmitted. The temptation to run flywheels at high speed ts 

 therefore very great, so great, in tact, that they are often run at a speed 

 dangerously close to the limit of safety. To yield to this temptation Is 

 deliberately to invite disaster. 



Failure of a llywheol usually begins by the starting of a minute crack 

 on the under surface of the rim at the point of greatest stress, viz., near 

 the ends of the arms adjacent to the rim-jolnt. The cracks gradually 

 deepen until failure occui's with all its disastrous consequences. These 

 minute cracks are visible to an experienced eye, and careful inspection 

 will aid materially in the prevention of flywheel explosions. In wheels 

 built in sections, care should be taken to see that the Holts are properly 

 drawn up. 



Wood Stands Up Under Fire 



Illustrating the remarkable Hre resistant qualities of wood, the accom- 

 panying cut gives a convincing demonstration that wood is by no means 

 so dangerous a building material as some folks try to represent it to be. 



The picture shows the framework on which is carried a very heavy 

 traveling crane for handling logs for a certain well-known veneer mill. 



A large part of this plant was entirely destroyed in 1916. and the crane 

 shown in the illustration was built right up along side ot the frame struc- 

 ture which was burnt. In fact, the building was just as high as the tres- 

 tlework on which the crane is carried. Thus the timbers were literally 

 bathed in flames during the entire period ot conflagration. 



This trestlework is made of 8xS oak timbers, and the best indication of 

 the way it is done up is seen in the fact that it is now doing the same 

 service as before the Hre and not a nail or board has been changed. The 

 surface was penetrated for a depth of possibly a quarter of an inch and 

 there the damage ceased, and the strength of the structure was not 

 injui-ed in the slightest. 



ISATIIED IN FLAME BUT UNDAMAGED 



