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ii Sawmill Resaw and Power Problems A 



The growing use of the resaw in lumber manufacturing has given 

 an opportunity for sawmill men to study the machine and the best 

 way to utilize it. While not all lumber manufacturers believe that 

 the resaw is adaptable to every purpose— and in view of the wide 

 range of conditions under which sawmills are operated it would be 

 asking too much to expect that^it would fit the needs of everybody 

 in the business— those who have used it under the right conditions 

 are enthusiastic as to its possibilities in the direction of increasing 

 production and lowering manufacturing costs. 



The right conditions appear to be those under which there is sn 

 ample supply of timber, and where the profits are made through 

 putting out the maximum quantity of lumber. In the ease of the 

 small mill, which must study each log carefully as it goes through, 

 and must make out of each one the best possible lumber that can 

 be produced, altering the thickness according to the requirements of 

 this test, it must be admitted that the resaw cannot do the operator 

 much good. Hence it is logical to expect to find, and actually to 

 find, resaws ;ised most successfully in the big operations where 

 quantity, produced under uniform conditions, is desired, rather than 

 a relatively small output varied as to thickness by the necessities of 

 getting the best grade that the log will produce. 



In this connection an interesting plan has been used by one of 

 the big sawmill men of the southern hardwood country. Instead 

 of using his resaw for the output of one band mill, as is usually 

 the ease, he has planted his resaw where it may receive the lumber 

 cut by twin mills. Thus there is a regular tide of thick lumber 

 descending on the resaw and going out thin, and while it sounds 

 like asking a good deal of the crew of the resaw . to handle twice 

 as much lumber as the men who are handling the operation of the 

 band mills, it is not such a hard proposition after all. 



It must be remembered that since the resaw can be fed contin- 

 uously, while the band mill necessarily loses time after each cut in 

 getting back in position for another, the resaw ought to be able 

 to cut twice as much lumber as the band mill, and then some. 

 And by putting it up to the resaw to take the product of two band 

 mills, the lumberman has a chance to get his quantity cut at a still 

 lower figure than when the resaw is asked to cut thin lumber out of 

 thick for the output of only one band mill. 



In the instance noted the plan has worked beautifully, and the 

 sawmill man is well-pleased with the success of the idea thus far, 

 believing that it has made his resaw much more valuable than it 

 would be if it were used in the regulation fashion. While resaw 

 manufacturers do not stress this proposition, it is probable that 

 they would find it worth investigating, even though it might be 

 too extreme to justify recommendation as a general proposition. 



A big sawmill man who has always believed in the use of the resaw 

 has devised a plan of operating it which is somewhat out of the 

 ordinary, but which he thinks will be economical. That is the 

 installation of separate power equipment to take care of that par- 

 ticular machine. Everybody knows that a big resaw eats power 

 pretty fast, and consequently a mill which is running a resaw must 

 have pretty large power facilities. In this case the millman decided 

 to put a resaw in his plant, which was comparatively new, and was 

 confronted with the question of installing a new boiler and a larger 

 engine. Instead of putting the new equipment in the present power 

 plant, and operating it all as one battery, he decided on the other 

 scheme, and the resaw will be run under its own power, that is, 

 with energy developed in a plant reserved for that particular pur- 

 pose. 



The advantages of the plan are numerous. In the first place, 

 since, as stated, the power production of the mill must equal the 

 maximum requirements of all the machinery, and where a resaw is 

 used must be able to take care of that load as well as others, the 

 power capacity would be much larger than is necessary when the 

 resaw is not in operation. And as there are occasions when con- 

 ditions do not require the operation of the resaw, it would be a 



— :^4— 



big waste of power to be producing enough to run the additional 

 equipment if the latter were not being operated. 



The same argument which applies to the use of individual motors 

 is applicable to the proposition of special power equipment for the 

 resaw. You use power only when your machine is running. While 

 the coupling up of individual power units is not advisable in a steam 

 plant as a rule, and only when a large unit like a resaw, derrick 

 or similar proposition is concerned, it certainly has advantages in a 

 case of this kind. 



Another benefit to be derived from the plan is that it will 

 enable the cost of the operation of the resaw to be figured more 

 exactly than under the other plan. Inasmuch as the sawmill man 

 who has devised this scheme is using the resaw for the first time, 

 although he has always been inclined to favor it, he wants to 

 know just what it is costing him to run it, and whether he is making 

 money on its operations. If it were being run with power from the 

 main plant supplying the rest of the mill, it would be difiicult to 

 figure how much of the power produced was being consumed in the 

 resaw. With its own power units operated to take caie of its indi- 

 vidual requirements, however, it is a simple matter to separate the 

 consumption and charge to the resaw just the expense of the power 

 that is consumed. 



And the interest on the investment in the resaw itself plus its 

 power equipment can likewise be calculated easily, thus making it 

 an easy matter to get the ' ' dope ' ' on the machine from one end to 

 the other. The sawmill operator believes that by the time he has 

 had his resaw in use for six months he wiU have some interesting 

 figures as to the cost of running it, and likewise as to the cost of 

 producing lumber when it is in use. As he has been running his 

 mill for several months without it, his comparison of figures ought to 

 be a striking demonstration of whether or not the resaw is all that 

 its advocates claim. 



Speaking ' of the power question reminds one that the average 

 sawmill burns up a lot of power that it doesn't use. Of course 

 power is cheap when fuel is found in the waste of the plant, but at 

 the same time, there is no need of wasting it, and frequently added 

 boiler capacity with a rearrangement of the transmission system 

 would enable the old plant to take care of all requirements. One 

 of the easiest ways to lose power is through improper adjustment 

 of shafting. If it is not lined up perfectly true, the transmission 

 of power from the engine to the machine will be accompanied by 

 losses which would amaze and impress the most careless millman. 

 One of the disadvantages of ordinary sawmill construction is the 

 use of timbers as supports for shafting. In many instances these 

 gradually sag and get out of line, with the result that friction occurs 

 and the belt tightens up and pulls hard on the pulleys. In most of 

 the newer sawmills this feature has been taken care of by the use 

 of concrete supports for the piers holding the shafting, so that 

 there is less danger of it getting out of true. 



The use of more transmission equipment than is really needed is 

 one of the defects most frequently noted in sawmills. A graphic 

 instance of this was given recently when a millman who had 

 exhausted the timber on a tract which he had been working for 

 several years moved his mill to a point further south. His operations 

 previously had gradually developed, new equipment being put in, 

 and additional countershafts provided, with a multiplication of gears 

 and belts, so as to take care of all the various units requiring 

 power. When prepared to put in the second mill, he asked his 

 superintendent to figure out the best method of arrangement of the 

 machinery so as to reduce the power requirements if possible. 



' ' We are going to have to buy another boiler and increase the 

 size of our engine, ' ' he said, ' ' unless we can figure out a system 

 of cutting down our power requirements, for the reason that we shall 

 have some additional sawmilling machinery at the new plant. See 

 what you can do. ' ' 



The superintendent and the engineer got together and after 



