HARDWOOD RECORD 



21 



reicrreii to. since the sawmill operator can see the changes iu iiia 

 market and take advantage of them without having to be a seer, 

 as at present, when he is from three to six months away from the 

 consumer, in point of delivery possibilities. 



The furniture man is determined to "let the lumberman carry 

 the stocks. ' ' The lumberman has been carrying them all alon;;, 



and will continue to do so. The actual consumption will remain the 

 same, and it will cost no more to deliver steadily on contract than 

 to pile up a lot of lumber in a consumer's yard and wait for it to 

 be used before making another delivery. It will merely save 

 the consumer a lot of expense and trouble, and will not be dis- 

 advantageous to the lumberman in any appreciable degree. 



> !B^y>^Aa!/^y.■>i;:v:;it!)^!;i^^Lk:^'^^<^.^;<x«H!>^;/^;>>c;M:^;^;;^;^^ WiOWls^H*!) '" 



A Question in Veneer Trimming 



One of the questions of the day which is just beginning to push 

 itself forward noticeably is that of veneer trimming — when and 

 how often veneer should be trimmed between the time of cutting 

 and its final use. 



Usaally the veneer user passes this question by on the theory 

 that it is no concern of his when or how often veneer is trimmed 

 just so he gets the material in shape and size to suit his need at 

 the time of using. It does interest the veneer user, however, as 

 well as the veneer maker, mainly because it is a question of 

 utility or efficiency in utilizing timber, but also partly because 

 there is involved a matter of getting the veneer to be used in 

 exactly the shape that he wants it. 

 . To understand this matter of trimming veneer, what it means 

 and all its aspects and the when, why and how of it, we must 

 go back to the time and place of its production and then follow 

 it through to the finishing room. 



Usually when rotary veneer is being made there is a part of the 

 end of the block that is trimmed off in the process of cutting, 

 being separated from the main sheet by what are termed score 

 knives. This gives a veneer product which consists of a straight 

 sheet or ribbon of veneer uniform in width or length and with the 

 ends trimmed exactly square with the cutting and parallel with 

 each oiher. It naturally makes a more presentable sheet of veneer 

 than if the score knives were not used and the entire face of the 

 block were peeled off because then there would be some irregularity 

 in the width of the ribbon or the length of the veneer, and this 

 is objectionable in a way. 



Usually when the veneer is peeled out in this way it is cut up 

 into dimensions of some kind. One may make it a business to cut 

 to a size that will allow for shrinkage in drying and the final 

 trimming to the exact dimensions required. Another may clip his 

 veneer out in long sheets, as long as can be handled, and dry 

 these sheets before clipping to dimensions. 



In following this process the first noticeable feature about it 

 ig the waste incident to the end trimming by the score knives. 

 This waste varies from one inch at each end to as high as three 

 and four inches, sometimes, and in the course of a day's run it 

 counts up considerably. If the logs are brought into the veneer 

 mill in long lengths and are freshly cut with a drag saw before 

 working, it is^ practicable, by careful attention, to reduce this end 

 waste to a minimum of approximately one inch to each end. 

 Where the logs are cut to short lengths in the woods, however, there 

 is some checking in the ends and for this reason a more liberal 

 allowance is made for end waste, the allowance being approxi 

 mately three inches for each end. 



One might well argue that it is immaterial whether this extra 

 end length is trimmed off and thrown in the waste pile at the 

 veneer machine or afterward. Indeed, one might urge that the 

 sooner it was trimmed off and disposed of the better because it 

 saves the handling of the waste through the driers and the trim 

 mers and so on; hut another factor enters there, which concerns tin- 

 veneer user as well as the veneer manufacturer. It is the factor 

 of shrinkage. 



Veneer does most of its shrinking, though not all of it, side 

 wise. This is well known and understood. But the side shrinkage 

 is not always uniform. There is some end shrinkage and there 

 it also enough irregularity in the side shrinkage to draw the ends 



out of square and make another trimming necessary to straighten 

 them out. 



There have probably been wrangles galore over this matter of 

 end shrinkage in veneer, mainly because we are too much in the 

 habit of taking the attitude that end shrinkage is small, insig- 

 nificant, and therefore needs but little attention. It is a known 

 fact that where men are cutting drawer bottoms or other single ply 

 stock to fit into grooved spaces neatly and cutting to exact dimen- 

 sions with score knives at the veneer machine, it often turns out 

 that the stock fails to fit. It will be short in length, it will be 

 found so out of square that the sides and ends will not fit up at 

 the same time. Then will come the charges from the user that the 

 veneer manufacturer did not cut to specifications, and the veneer 

 manufacturer will accuse his veneer cutter of carelessness in fol- 

 lowing instructions as to length. 



The only way to get exact dimensions in veneer is to make those 

 dimensions after the veneer is thoroughly dry. Cutting to specific 

 dimension in either length or width before drying will result in 

 disappointment if the requirements are very exacting. To give 

 satisfaction where the requirements are exacting as to dimensions, 

 the trimming to size must be done after the veneer is thoroughly 

 dry, and generally it is best to do it with saws. Some thin veneer 

 is cut both crosswise and lengthwise with knives but to get the 

 best results in trimming veneer to size the ideal way, either with 

 thin veneer or thick, take it in bulk and trim it with saws. 



This being true, the question naturally rises as to whether veneer 

 should be trimmed twice or only once, whether it should be cut 

 to length with score knives and made long enough for a re- 

 trimming, or whether the score knives should be abolished and one 

 trimming made to do it all. 



The answer to the question depends somewhat on circumstances. 

 Some trimming is quite often essential before drying. This is 

 true especially of side trimming. Sheets of veneer must be cut 

 to some sort of dimensions so that they can be handled, and in 

 cutting to these dimensions notice must be taken of the final size 

 requirements and allowance made for shrinkage in drying and 

 for the final trimming to size. It requires the exercise of some 

 care in making this allowance to prevent unnecessary waste on 

 the one hand and to prevent an unusual amount of culls through 

 lack of width on the other hand. 



The usual allowance for shrinkage in width is ten per cent — 

 one inch for every ten. Some woods, notably maple, will not 

 shrink this much, but gum will come very near it. The shrinkage 

 allowance would be the same whether the veneer sheet is cut up 

 into individual sizes or into sheets of two or three sizes. If the 

 final dimensions are small, however, a saving in trimming allow- 

 ance may be effected by handling the sheets in multiples of the 

 final size. 



In the end shrinkage and allowance for trimming we might 

 argue that since there must be a final trimming after drying, the 

 score knives should be taken off and let the full length of the 

 block go into the sheet with all its variations in alignment with 

 the sheet. This argument is good, too, where the veneer is being 

 dried, shipped and handled single ply. It involves only the drying 

 and shipping of that extra length, and in return the extra length 

 insures better stock after the final trimming and more room to 

 do the trimming. 



