SLACK COOPERAGE 133 



should be about 45 to 60 ft. in length, 8 to 10 ft. wide, and 5 to 7 ft. deep 

 and made of concrete or yellow pine. Some plants boil their hoop plank 

 standing on end, as they claim that best results are secured when each 

 plank is separated from the others, which is difficult or impossible when 

 the planks are laid flat in the horizontal tanks. 



The heat applied and length of boiling depend upon the condition of 

 the stock. All that is required is to soften up the fibers so they will cut 

 easily. 



While still hot the planks are taken to the hoop cutter, which should 

 be adjusted to cut the hoops slightly thicker than the finished size to 

 allow for planing. Hoop-cutting machines are usually run at a speed 

 of 200 R.P.M. and have a capacity of 60,000 to 75,000 cut and beveled 

 hoops in ten hours. Next the hoops are planed in special machines that 

 dress three hoops at a time and have a capacity of 30,000 to 35,000 

 hoops per day of ten hours. They are then pointed and lapped on 

 other special machines and sent to the coiling machine. 



As to the relative advantages of cut and sawed hoops there has been 

 much discussion. Many more hoops can be made from a given amount 

 of timber by the cut process than by the sawed process for the reason 

 that with cut hoops there is no loss in sawdust. It is estimated, for 

 example, that 1000 bd. ft. of elm logs will make 4000 cut hoops as 

 against 3000 sawed hoops. Hoop-cutting machines will turn out from 

 40,000 to 60,000 hoops per day as against 15,000 sawed hoops per day. 

 However, the machinery used in sawing hoops is much more portable 

 than the other, it requires much less capital and skill for equipment and 

 maintenance and the sawed hoop is generally considered in the trade to 

 be superior. The last argument seems to be true, because in the cutting 

 process the knife is inclined to shatter the wood in forcing its way through 

 the fibers which results in materially weakening the hoop. 



The hoop-coiling machine is an ingenious device to coil the hoops 

 while still hot from the vat whether made by the cutting or sawing 

 process. Several makes have a capacity of from 15,000 to 20,000 or 

 more per day. If the hoops are not hot when coiled, there will be much 

 breakage and splintering in consequence. After coiling the hoops are 

 carefully stacked in an open air shed and thoroughly dried before ship- 

 ment. Coiled elm hoops are made in many dimensions, varying in 

 finished lengths from 3 ft. 6 in. to 8 ft. 6 in. 



