128 FLAX CULTURE AND PREPARATION 



numbers, and arrangements of pairs of fluted rollers or their 

 equivalents. In some instances the surface speed of all the 

 rollers is the same, in others a very slight lead is given to the 

 flax as it nears the finishing end. In most machines the 

 rotation of the fluted rollers is uniform and forward, in some, 

 however, the motion is alternately forward and backward, but 

 with a greater forward motion. In one instance a set of rotating 

 and intersecting steel bars or skeleton drums was employed. 



But whatever mechanical method is adopted and however 

 perfect that contrivance may be, if the flax is hard and coarse, 

 and badly watered, it will not yield more than two -thirds or 

 a half of clean scutched flax as compared with a similar quantity 

 of perfectly retted and dried flax. 



110. Breaking Rollers. At the present time the machines 

 most generally used for breaking the woody pith consists of 

 a series of pairs of fluted iron rollers arranged in a horizontal 

 plane, some rotated by bevel and others by spur-toothed 

 gearing. The rollers of the different machines are approxi- 

 mately 3 ft. long and 6 to 8 in. in diameter. The " flutes " 

 in some machines are J to TG in. " sharp " and \ to J in. deep. 

 On some machines the pitch is | in. at the feeding end and is 

 gradually reduced to \ in. at the finishing end, in which case 

 too, it is proportionately shallower. 



In some machines the pitch is If in. at the feed and gradually 

 reduced to f in. at the finish. The object in varying the pitch 

 of the flutes is to break the wood in the greatest possible 

 number of places. 



In all cases the bottom fluted roller is positively driven and 

 the top one by friction. Pressure is applied to the top rollers 

 by means of springs, weights, and levers. Rubber cushions 

 are sometimes fixed above the springs, for the purpose of 

 causing a slight yield in the pressure whenever any hard 

 substance is associated with the flax straw. 



111. Fluted Breaking Rollers. Fig. 77 is a plan showing 

 seven pairs of fluted rollers with bevel gear method of driving 

 same. 



