UTILIZATION OF BLACK WALNUT. 47 



against the knife, and the straight-slice method in which the timber 

 mo v^es in a straight line. 



Rotary-cut process. — This process has been used extensively for 

 making veneer. It is still the method in most common use, for it 

 has the advantage of a low cost of production. 



Walnut veneer logs are sawed into the lengths required for the 

 veneer that is to be cut. These sections are put in hot water, gen- 

 erally over night; hard material may require a night and a day, or 

 even two nights and a day. Each log section is then taken out and, 

 after the bark is removed, revolved in the rotary machine, which is 

 constructed like a lathe. The knife is constantly advanced, the ad- 

 vance for each revolution of the log corresponding to the thickness 

 of the veneer. The veneer is usually torn off where a defect occurs, 

 often at each revolution. Logs may be sliced down to a diameter of 

 6 to 8 inches, depending on the machine. Some specially constructed 

 machines cut down to a diameter as small as 4 inches. The figure 

 in this veneer is made by the growth rings, and, since the slicing is 

 done in the direction of these rings, a veneer with a large coarse 

 figure is the result. Hence only the lowest grade of logs is cut in 

 this manner. Moreover, a considerable part of the heartwood, and 

 usually the most valuable part, is wasted in the core. If the center 

 of the log is defective, there is some advantage in slicing by the 

 straight rotary process. 



A variation of the rotary is the half-round process, by which the 

 log is set somewhat off the center, and veneer is cut only part way 

 around the log. This method is most commonly used with small logs 

 in which there is a small amount of heartwood. The veneer may be 

 sliced from the heartwood in this way, whereas by the straight rotary 

 process little or no veneer can be obtained from the heartwood of 

 small logs. If they are trimmed, successive sheets may be matched 

 up for panel work. After the slicing of two sides of the log, the 

 rest may be straight sliced and will yield quartered stock provided 

 the central portion of the log is not defective. If the log is not 

 sufficiently clear for veneer, it may be made into dimension stock. 



The stay-log rotary process is a development from the rotary 

 method proper, and is now very largely used for walnut. In this 

 process a heavy flat plate is set off center, at a distance of about 1 

 foot, to which the timber to be sliced is fastened. The walnut block 

 to be sliced is in the form of a half -log, generally called a flitch, and 

 the sapwood is largely trimmed off (PL V, fig. 1). Holes are then 

 bored in this flitch to correspond with those in the plate, to which 

 it is to be fastened with stay bolts. By this method the heartwood, 

 which must be thrown away in the core in the straight rotary method, 

 may be more closely utilized. 



