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Experience Talks on Woodworking 



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When a planer pulls hard and seems to take more jjower than it 

 should, do not assume immediately that the knives are dull or that 

 jou liave taken too heavy a cut, but investigate and analyze it. 



If the knives are requiring too much power, this will generally 

 manifest itself in a strain on the cutter-head belts. Even then, 

 though it may not be due to dull knives or deep cutting, it may be 

 due to tight journals or to any one of several causes. The knives 

 may not be ground slender enough and the heel of the bevel may be 

 striking. They may be too close to the lip for the kind of work they 

 are doing, thus making the cutting unnecessarily heavy. In fact, 

 there are a number of things that may use up power, and those sug- 

 gested here are only a few of them. 



There is really more unnecessary power used up in the feeding 

 mechanism of the average planer than anywhere else. Sometimes this 

 is hard to avoid because it is essential to hold the stock firmly as it 

 passes through the machine to get good work. One can minimize the 

 piower required, though, by a careful analytical study of his machine 

 and its adjustment and by proper lubrication. Sometimes the pressure 

 bar may be unnecessarily tight, the feed roUs may be coming down 

 heavier than is really necessary, or the stock may be running so flat 

 on the bed plate that it drags hard. Possibly it can be improved 

 with a little lubrication on the bed. Anyway, there is always room 

 to study every detail of these things carefully. It will not only help 

 save power, but is a great aid to understanding thoroughly the work 

 of the machine, and frequently in the process of eliminating waste 

 power one will also be led into doing better work with the machine. 



Considering the question of motor drive, in the final analysis it 

 would seem the question of using individual drives for all the small 

 machines in a plant, as well as the large ones, is more a matter of 

 motor cost than anything else. The best authorities on the subject 

 seem to agree that there is hardly a thing, from the spindle of a bor- 

 ing machine up to the heaviest drive in the shop, that cannot be made 

 with an individual motor. Whether or not it is always advisable to do 

 this depends more on motor cost than on relative power cost. 



It involves quite a sum of money to put individual motors on all 

 machines. In some instances the cost of the motor would amount to 

 more than the cost of the machine itself, and there are very likely 

 many instances where this outlay in first cost would not be justified 

 by the advantages gained. 



It is noticeable that the man who gets individual motor drive sel- 

 dom wants to change, but even the ardent advocates of electric drive 

 seldom advise the provision of individual motors for aU machines. 

 Groups of light machines can be driven from one motor, and the in- 

 vestment in motors reduced without any great inconvenience and 

 without impairing the elfieiency of the driving system. 



Perhaps, by and by, motor cost itself will be reduced. Anyway, 

 with motor cost as it is at present, there is a strong inclination to 

 go more and more toward individual motors, where electric transmis- 

 sion is used. 



There is a strong tendency now to dispense with a lot of counter- 

 shafting formerly used in driving woodworking machines, and the 

 electric motor and the high-speed lineshaft are doing it. It is easy 

 to understand the high speed and light sizes in connection with elec- 

 tric motors, but even among those not using motors there is the same 

 tendency to use lighter shafting and run it at higher speed. It helps 

 to reduce the friction load by making the shafting and pulleys 

 lighter, the belts smaller, and the strain or i)ull less. With some 

 machines there is still the need of the countershaft, no matter what 

 the speed of the line (such machines as fourside moulders, for ex- 

 ample), so as to get belting oonuections and pulley alignment for 

 all heads. But there are many machines, like ripsaws, which may well 

 be driven direct from the high-speed lineshaft, with a clutch pulley 

 for cutting in and out, instead of the regulation counter, with its 

 tight and loose pulley and the shifting belt. Indeed, there is room 



for ehmmating more of the counters than one would surmise at first 

 glance, for the clutch pulley can easily take the place of the belt 

 shifter, with a possible saving in both equipment and power. 



Good machinery is not more essential to the success of a manufac- 

 turmg enterprise than is a thoroughly modern office and factory sys- 

 tem. Every machine in the plant m:iy be of the latest and most ex- 

 pensive type, but if the system upon which the business is conducted 

 IS antiquated and ineflScient, the organization is behind the leaders 

 and in a fair way to meet with disaster. 



Practice has disproved the predictions that band saws would not 

 successfully saw yellow pine logs because of the resinous gums they 

 contain. Predicting what machinery wUl not do is about as certain 

 and satisfactory as predicting what the weather will be. 



The crosscut filer in the woods may not study the science of filing 

 like the man in the mills, but he nubs after the' knack of making his 

 saws eat wood and pull light in a way that usuaUy delivers the goods. 



A tight belt to a pulley fastened to a shaft midway between bear- 

 ings is likely to become a troublesome proposition, for the shaft is 

 quite apt to spring. 



It may be the number of feet going through the mill that makes the 

 sawyer '.s talley, but it is the quantity and quaUty that he gets from 

 each thousand feet of logs that finally makes his reputation— and is 

 often a deciding factor in the mill 's chance for profits. 



Bright, clean machines may not do any more or better work than 

 dirty, greasy machines, but they make one think that the mill in 

 which they are operated is up to date and well managed. Then, 

 too, the insurance man never fails to note the diflference. 



Elements Impair Strength of Wood 



Little iliagoual streaks or wrinkles across the grain of a piece of 

 timber not only betray weakness, but sometimes indicate periods of 

 stress through which the wood passed when it was growing. They 

 may even be taken as a sort of check on the official record of wind 

 storms, as in the ease of some lumber tested at the Forest Service 

 Laboratory at Madison, Wis. 



The marks are caused by what are called "compression failures," 

 wliich occur when the fibers bond or buckle under a too hca\-y strain. 

 In cutting up logs collected for experiments at the laboratory, it was 

 noticed that these compression failures appeared on the north side of a 

 number of trees which came from the same locality in Florida. By count- 

 ing the annual rings of the wood and from knowledge of the time 

 when it was cut in the forest, it was decided that the compression 

 failures must have been caused by a severe wind from the south about 

 the year 189S. Inquiries were made in Florida and it was found that 

 a hurricane had, in fact, swept over the region at the time indicated. 



The experiments have determined that the strength of a piece of 

 wood may bo seriously impaired by slight compression failures due to 

 rough handling. Dropping a beam across a skid may cause a com- 

 j)ression failure at the point at which the beam strikes the skid and 

 it will be at this point that the beam gives way when it breaks under 

 a strain too severe for the weakened fibers to withstand. Hitherto 

 unaccountable breakage in hickory wagon spokes and other pre- 

 sumably strong material is now attributed to compression failures 

 caused by wind storms in the period of growth or by hard usage in 

 lumbering and manufacturing processes. 



Boxmakers in the United States use more than 4,500,000,000 board 

 feet of lumber each year, or more than one-tenth of the entire lumber 

 cut of the country. 



In northern Idaho and Montana, which had many fires during the 

 past summer, thirty-five per cent of the fires on national forests were 

 caused by railroads, twenty -six per cent by lightning, and ten per cent 

 by campers. The remainder were due to brush burning and other mis- 

 cellaneous or unknown causes. 



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