96 FOREST PRODUCTS 



which consume it. Few mills are supplied by the company's own logging 

 operations. Logs are customarily purchased in carload lots from logging 

 operations or from wood lots in the vicinity. As only the better class of 

 logs are used, logging companies frequently set aside their veneer logs 

 until they have a sufficient supply for a special shipment. There are no 

 universally adopted rules for grading logs accepted at veneer mills. 

 Individual mills have their own rules and uniformity in them is now being 

 considered in the industry. 



As the logs are unloaded at the plant they are left in an open yard just 

 outside the mill and rolled in as needed. A few of the largest mills have 

 storage ponds similar to those in use in connection with saw mills. The 

 advance supply kept on hand is often so large that serious deterioration 

 takes place due to checks, rot and insect attack. Seasoning is not neces- 

 sary ; in fact, green logs are preferred. 



The machinery and equipment usually found in the modern rotary 

 veneer plant consists of a drag-saw or cut-off saw to cut the logs into 

 desired lengths, a vat for boiling or steaming, the rotary veneer machine 

 or lathe, a clipper to trim the veneer into the desired sizes, conveyors, 

 a wringer, a die cutter, a dryer and a knife grinder. When built-up stock 

 is made, power or hand presses and glue-room equipment are added. 



The following is a brief description of the usual method followed: 



The logs come in even lengths up to i6 to 20 ft. long, and must be cut 

 down to from 38- to 52-in. logs, which are the lengths usually used on the 

 veneer lathe, or to 6, 7, 8, g or 10 ft. in length depending upon the width 

 of veneer desired. They are rolled into the mill by hand or by the use 

 of heavy cranes, or on a log hoist when a mill pond is used for storage 

 purposes. 



The cut-off saw, either of the drag, horizontal band or circular type, 

 cuts the logs into the desired bolt lengths, which are conveyed to the 

 steaming or boiling vats in order to soften the fibers for cutting. In the 

 former, live steam is turned into the pits but no pressure applied. Boil- 

 ing is the favored method because it heats the logs more evenly and the 

 logs remain in good condition for cutting for hours, whereas steamed logs 

 should be cut immediately after heating or they become hard and brash. 



There has been no determination and common acceptance of the 

 length of time or degree of temperature to be followed in boiling. Many 

 mills fill the pits each morning with sufficient bolts for the next day's 

 run and leave them there overnight. The usual size pit will hold from 

 600 to 1000 ft. board measure of bolts. Heat is applied by means of 

 steam pipes. 



