April 10, 1917 



Hardwood Record — Veneer & Panel Section 



23 



How Thick Should Face Veneers Be? 



Sanding Methods Emphasize a Question Which Is of General Importance 



UTTING PANELS THROUGH THE SANDER 

 is always a more or less ticklish job, in view 

 of the possibilities of spoiling a piece by cut- 

 ting through the veneer. If a face veneer is 

 damaged in this way, it is possible to patch it up in some 

 cases, but the job is always relatively unsatisfactory. In 

 view of the labor and overhead expense which have gone 

 into the manufacture of a panel up to the sanding point, 

 it is obvious that the loss of one through an error of this 

 kind is more than is represented by the value of the 

 material which it contains. 



This has demanded careful adjustment of the drums 

 so as to cut just enough, and careful attention to the 

 sandpaper to avoid any stretching, which is likely to 

 cause the application of too much pressure at a certain 

 point, and cutting through there. Some of the sanders 

 have automatic adjustments which control this feature, 

 while others need to be adjusted by hand. But this is a 

 proposition which is of obvious importance. 



In this connection a big veneer manufacturer and job- 

 ber, who handles a lot of fancy face veneers, said re- 

 cently that he had noticed an increased call for thicker 

 veneers of late from some of the important panel manu- 

 facturers. This demand involved supplying veneers 1 20" 

 to 1 '24" thick instead of those which are 1 28" or 

 1/32". The veneer man said that the explanation given 

 him was that the newer types of sanders are taking off 

 more, and that in order to "play it safe" the panel men 

 were using somewhat thicker stock. 



Investigation of this suggestion among machinery 

 manufacturers indicated that no radical changes in San- 

 der design have been made. One concern is putting 

 out a Sander for which greater speed is claimed, but it 

 is contended that it is possible to adjust it so accurately 

 that no matter how thin the veneer there will be no 

 danger of cutting through. Stock no thicker than 1 '32", 

 it was stated, can be handled w^ithout any difficulty, even 

 at the increased speeds at which the machine is operated. 



On the other hand, it has been pointed out that speed 

 in sanding is not a matter of arbitrary decision, but is due 

 simply to the ability of the sand-paper to cut the wood. 

 The reason sanders are operated at slow speeds is be- 

 cause the capacity of the abrasive material is limited. 

 Increasing the production of the machine is therefore a 

 question of improving the methods of sanding, appar- 

 ently, as the speed ratio is the result and not the cause. 



But without attempting to argue the point with the 

 machinery experts, the fact that some condition connect- 

 ed with sanding panels has suggested the use of thicker 

 stock is sufficiently interesting in itself to invite attention. 

 In fact, the writer believes that such a development is to 



be commended, because the tendency in the other direc- 

 tion has been so strong as to be positively dangerous. 



About the only kind of veneered work which has been 

 given all that is coming to it in the matter of thickness 

 is veneered doors. Those that are exposed to the ele- 

 ments, it is realized, must be properly protected, not only 

 by the use of numerous coats of varnish, but by a thick, 

 sheet of veneer. Hence it is customary to find veneered 

 doors placed in exposed positions with face veneers of 

 J/g" or thicker stock. Door panels generally, however, 

 have been made of exceedingly thin material, insomuch 

 as these surfaces do not come in contact with objects 

 which are likely to damage them, and the thin material 

 is therefore safe. 



But when it comes down to the manufacture of 

 panels and tops for furniture, which gets notoriously hard 

 usage, a different plan has been in evidence. From 

 relatively thick surfacing veneers, which were demanded 

 in the early days of veneering, manufacturers have been 

 cutting down to material which is, in the opinion of many, 

 dangerously thin. That thirty-second stock is in use and 

 ■ ving a reasonable degree of satisfaction may prove 

 that this is thick enough; and then, again, it may only go 

 to show that defects which are not serious enough to 

 volve rejection in themselves result ultimately in the 

 work getting into a condition which is a reflection on ihe 

 furniture manufacturer and on the concern which sup- 

 plied the veneered w^ork. 



In the first place, as suggested, using excessively thin 

 veneer stock means that the danger of damage in sand- 

 ing is increased. The "take-a-chance ' idea back of this 

 proposition is not in line with modern standards of manu- 

 facturing glued-up w^ork. The essence of good workman- 

 ship is care as to the details, and using material which is 

 thinner than it should be violates the first principle of 

 the proposition. Taking a chance should be eliminated 

 in favor of safety first. 



Another point in this connection is that every engineer 

 believes in having a margin of safety to go on. If mate- 

 rials were figured only with a view of taking care of 

 normal stresses, accidents would be much more frequent, 

 because abnormal conditions, which cannot be specifically 

 foreseen, are constantly occurring. In order that they 

 may be met without danger, the engineer provides a 

 factor of safety broad enough to take care of unforeseen 

 strains and stresses, and thus insures the permanence of 

 his structure. 



In building up tops and panels the margin of safety 

 should be provided at the point where it is most needed 

 — on the face. The corestock is always thick enough, and 

 the crossbanding is not subjected to the strains growing 



