August Ui, l'.t21 



HARDWOOD RECORD 



21 



By E. R. Whittin 



My cx|ii'ri('iui' and obsi'rvatioiis in workinf; with band saws has 

 sliown Mil- that in almost all I'ases whore cracked saws have come 

 into the filing roiini the craiks occurred either in the first run or 

 between the first and sixth runs. In other words, the bands cracked 

 while being broken in and adjusted. We filers have all had this 

 exjierit'Tic-r with new saws and in my opinion it is due to faulty 

 tension. II' the band is not cracked beyond all hope we simply 

 repair ami wear it out in service. However, experience and infor- 

 mation from men in the \)usiness has taught me some faets which 

 I am going to put In'fore you. 



Tile first few runs a band saw makes are the most iuipcirtarit in 

 deteruiiiiing flu- future of the saw. It is by the first six runs that 

 a filer makes his observations and forms his opinions of tliu saw, 

 satisfying himself as to the material and workmanship in Ihe saw. 

 I myself, do not believe in jiassing judgment after the first run, 

 but always give a leeway of about six runs in order not to use 

 .".nap judgment. There is a fact existing about all new machinery 

 and tools — they "work stifT" until broken in, as we all know. 

 The bearings must be worn in, etc. A b.-ind saw is no exception 

 to this rule. 



Let us look ;i little further into the band saw situation, and I 

 think you will bear with me in my arguments and assertions. Very 

 few bands coming from the steel mills or from liardening and 

 tempering in the same shape. Some conform to the back and 

 tension gauges more readily than do others. From this it follows 

 that in putting one band u)i more hammer work and rolling is 

 required, ])erhaps, on one than another. In man}' cases one portion 

 of a saw will be a quarter of an inch over or under the back gauge 

 and on either side of this portion the saw will fit to the gauge 

 nicely. It may run straight the entire remainder of the back. 



It follows quite naturally that more rolling and stretching will 

 be required in that portion which drops away or is full to the 

 gauge. The result is that in the first few runs which the new band 

 makes the parts which have been worked more in order to draw 

 up or bring down the back, will hold their tension much longer 

 than the [lortions which did not require so much rolling. This 

 results in uneven tension which gives the appearance of soft spots 

 or uneven temper. 



Let us take up another case of uneven temper or soft spots. 

 After a short run on the mill it is found that some parts of the 

 band have held their tension while others have not. Narrow, tight 

 spots will also show up in the center of the saw. This is caused by 

 rolling the tension — dropping the saw to fit the tension gauge in 

 the first tensioning. Naturally, when a saw has been rolle<l heavy, 

 the rolled lines are placed further apart than they would have been 

 had lighter pressure and more rolling been used. These tight spots 

 will always be found between the heavy rolled lines. This is often 

 called, as we all know, false tension, and is one of the reasons why 

 a new saw will not as a rule stand as deep a tension as one that 

 has been run. 



To sum up, the whole situation amounts to this; stretching takes 

 place from working the saw, and parts of the band which have 

 been worked more than other parts maintain their tension longer. 

 This condition exists until the band has thoroughly adapted itself 

 to conditions and has been adjusted uniformly all around to the 

 running bend from passing over the wheels. 



In breaking in new bands I have found by experience that a 



few points have helped me a great deal. It is always well to use 



a shaper on all new saws, grind the teeth to or near to the shape 



you are using, and then put on the bench. 



^ It is always advisable, in my estimation, in working over a new 



band to have the e<lges firm. Hunning the tension too close to thi- 

 edge (tooth edge especially) jiroves disastrous to miaiy a good saw. 



A new band will not stand as deep a tension as one which has 

 been stretched and adjusted uniformly. Put up an old saw so 

 that it will just lie flat on the leveling block, and put up a new 

 saw with the same gauge. It is difiicult to make th(^ new s;iw lie 

 flat on the block. This demonstrates the fact. 



A new band in other words is like a new machine of any kind 

 or like a new shoe. It has got to be broken in gradually. If w<- 

 try to force it, it is quite apt to result in a disaster to something. 

 This something is bound to be the band saw, because it is the 

 delicate part. In the case of the shoe, it is the man's foot that 

 usually catches the punishment. .\ band which has been thoroughly 

 worked with the rolls has the tension evenly distributed through 

 out the blade, and the strain likewise is evenly distribiiteil when 

 the band is running on the mill; whereas a new band in its fir.st 

 few runs has not been sufficiently worked over to have this tension 

 distributed evenly and therefore the strain is thrown onto the 

 fast spots between the rolled lines. Until the tension is evenly 

 distributed you will have these fast spots and an uni'ipi:i) distri- 

 bution of strain. 



Plan to Reduce the Time and Cost of Air 

 Seasoning Wood 



In co-operation with the sawmills and wood utilization plants 

 throughout the country, the Forest Products Laboratory, Madison, 

 Wisconsin, is organizing an extensive field study on the air season- 

 ing of wood. This study, it is believed, will be of extreme in- 

 terest to the lumber manufacturer and to the wood-using industries. 

 The purpose is to determine the i)iling practice which will result 

 in the fastest drying rates consistent with the least depreciation 

 of stock, the least amount of required yard space, and the least 

 handling costs. The study will be carried on concurrently on both 

 hardwoods and softwoods. All the impoi'tant comn)ercial woods 

 of the United States will eventually receive consideration. 



A tentative working plan of the air seasoning study has been 

 prepared by the Forest Products Laboratory, and copies are being 

 sent to the secretaries of the various lumber and wood-using asso- 

 ciations, state foresters, forest school heads, and others eminently 

 qualified to comment on the plan. 



Co-operation in the air seasoning study is being offered on every 

 side. As yet the plants at which the work will aitually be dom- 

 have not been definitely chosen, but the extreme interest alread.v 

 manifested indicates that there will be no difliculty in si'iuring 

 co-operation with plants ideal for the study. Actual fielil work 

 will soon be well under way. 



Reoomnundations will be made to Congress by the Adminis- 

 tration relative-to pulp wood lands in Alaska as aooii as the iuvi'sti- 

 gation which is now under way is completed. 



The question of the restrictions on Alaskan wood iuilii l.i.ds li.i:< 

 ueen taken up several times by the Cabinet and the Pre i<le;it him- 

 self is understood to be very much inti'rested in the whob situa'iou. 

 In addition to being a newsi)aiier publisher and, thereliMc, being 

 interested in the pulpwood situation, the President haf ividenci' I 

 much interest in the reopening of Alaska. It is understood that 

 high Government oflScials feel that the restrictions in Alaska 

 probably have been carried too far to allow the <le\elopmein of 

 these lands. 



