132 FOREST PRODUCTS 



finishing the hoops, one end is pointed while the other is " lapped " or 

 thinned down to a fine edge like a wedge. 



There are two methods of manufacturing coiled hoops and although 

 certain variations in the two processes may be found in different parts of 

 the country, they may be described as follows : 



Sawed Hoops. 



The timber for hoops is sawed into planks at a sawmill. They are 

 ripped on a self-feed gang rip-saw into hoop bars 1 1^ by xi in- in cross- 

 section, each bar being large enough to turn out two hoops. The length 

 may vary from 4 to 7 ft., depending upon the size of barrels they are 

 intended for. Rip saws 16 in. in diameter and running at a speed of 

 3000 R.P.M. have proven to give excellent satisfaction. 



The other machinery required for the manufacture of sawed hoops 

 includes a combined planer and a jointer or lapper, and in addition a 

 coiler. A great improvement over the old method is found in the Traut- 

 man sawed hoop machine which saws the hoop bar in two and planes, 

 points and laps the hoop in one complete operation. The process is, 

 briefly, as follows : One end of the bar is pointed by a re v^olving cutter 

 head and is then started through the feed rolls. A saw placed at the 

 necessary angle to produce the proper bevel, divides the bar into two hoops 

 while a planer surfaces the opposite sides of the hoops. As they pass 

 out, each hoop is lapped. Two operators are sufficient to run the 

 machine, which has a rated capacity of 15,000 hoops per day. The Ket- 

 tenring machine is another in common use. 



The hoops are conveyed to a boiling vat or tank made of wood, 

 which is about 7 ft. long, 5 ft. wide and 3 ft. deep. Here they are soft- 

 ened in the hot water which is heated by exhaust steam. They are then 

 taken to the coiling machines. 



Cut Hoops. 



The timber is sawed into planks of the same width as the hoop and 

 cross-cut into the desired length. In the cutting process, the following 

 machines are required — a hoop cutter, a lapper or jointer, a hoop planer 

 and a coiler. Before cutting the planks are steamed or boiled. For a 

 long time there was some discussion as to whether steaming or boiling 

 was better, but there is a general opinion among manufacturers that 

 boiling is more efficient and cheaper in the end. 



The size of the vat depends upon the capacity of the mill. For a 

 plant with a capacity of 40,000 to 50,000 hoops per ten-hour day the vat 



