76 BUI^UETIN OF THE BUREAU OF FISHERIES. 



12. The drill descends for the second hole. 



13. The drill rises. 



14. The blank turns another fourth of a revolution. 



15. Third hole is drilled. 



16. Drill rises. 



17. Blank turns. 



18. Fourth hole is drilled. 



19. Drill rises. 



20. Drill continues in its shorter circular orbit, to return into proper position for a 

 later blank. 



2 1 . Button chuck rises a little and releases the button. 



22. As the chuck passes beneath a suction tube the button is drawn up against a 

 small, fine screen in the tube. 



23. The button drops of its own weight upon a small trap. 



24. When a number of buttons corresponding to a given weight have accumulated 

 on the trap it releases and drops the buttons into a bucket. 



25. The tripping of the door or trap registers the number of buttons finished. 

 Another feature of the machine is the equipment of little screened suction tubes, 



some traveling, and some stationary, which draw away the dust whenever it is generated 

 by carving or drilling. The amount which the carving tool may be lowered to compensate 

 for grinding can be fixed by a large ratchet disk over the machine, which permits of 

 adjustment to the one-thousandth of an inch. 



When the fisheye pattern (cf. PI. XXXVII, fig. 3, buttons in second row from 

 top) is desired, a thin, revolving emery wheel, or a steel fish eye cutter, is placed so that 

 as the button passes from the carving orbit to the drilling (without central depression) 

 the tool swings down and at one stroke cuts out the fisheye. There may also be 

 an attachment for causing the blank to turn upside down, so that the back may be 

 hollowed out instead of being left flat or rounded, as is ordinarily the case. 



This machine as described is the double automatic button machine. Somewhat 

 older types are the single automatics, where separate machines embody the processes 

 of facing and drilling. These are still in use in some factories. A very recent addition 

 to the button machine consists in an automatic grinding and feeding attachment, 

 whereby the blanks are first backed and then dropped into the chucks from an endless 

 belt. As the machine is generally used, the blanks are placed individually in the 

 chucks by the attendant, usually a woman, who becomes very expert. 



It will be recalled that the blanks were tumbled before being backed. In conse- 

 quence, as they come to the automatic machine the back edges are slightly sharper than 

 the edges corresponding to the inside surface of the shell. It is possible, therefore, for 

 a deft operator to distinguish at the touch the outside surface from the inside and so 

 to place the blanks in the chucks that the one side or the other (as desired) will be 

 finished. There seems to be some difference of practice, nearly all manufacturers 

 believing that the inside gives the best finish, while some find a better product by 

 finishing the outside. Experiments made at the Fairport station do not indicate a 

 marked difference. Possibly a better or more uniform gloss is obtained on the outside, 

 while a more pearly "water" results from finishing the surface corresponding to the 

 interior of the shell. However, an obvious advantage in carving the inner surface 



