958 



Popular Science Monthly 



of the plates, after the bottom of this hole 

 has been stopped up with a short plug. 



It will now be found a very simple 

 matter to saw diametrically across, through 

 the entire pile of plates, with a fine-toothed 

 hack-saw. Care should be taken to make 

 the cut run straight through the center of 

 all the disks from the top to the bottom of 

 the pile. The paraffin mentioned acts as a 

 lubricant for the saw and prevents the 

 central portions of the small aluminum 

 plates from being bent. The dividing cut 

 should run midway between the two sets of 

 small holes near the center of the plates. 



As soon as the plates have been sawed in 

 half and after the plates have been slightly 



Strips of brass used as bearings can be moved 

 in or out and sideways for adjustment 



heated to melt out the wax in the middle the 

 nails near the center can be removed. The 

 small spaces between the plates can be 

 cleaned out with an old toothbrush, to 

 remove any small metal shavings which 

 may remain. Each of the two halves 

 should be like the one shown at F. 



One of the machine screws can now be 

 fitted with the two pieces of fiber men- 

 tioned and clamped to one pile of parts, so 

 that the machine screw fits into the semi- 

 circular hole now left in each small alumi- 

 num plate. 



The two pieces of fiber, which are held 

 against the brass plates by the tightened 

 nut, should be so positioned that the small 

 holes drilled in them line up with the 

 corresponding holes in the brass plates, 

 which should now be filled with putty, and 

 this should be smoothed off flush with the 

 plates on the inside. 



A semi-circular mold should be made by 

 boring a ^-in. hole in a strip of soft wood 

 about I in. wide by ^-in. thick, to within 

 1/16 in. of one face of the piece, and then 

 splitting this piece in the direction of the 

 hole through the center. The two halves 

 are then finished by making a cut the full 

 length of each hole, thus forming the 

 wooden mold shown at G. In this view 

 one piec.i is shown in position at the top 

 while the lower piece is tilted back to show 

 its construction more clearly. 



When properly clamped in place this 

 mold can be filled with melted lead, which 

 should be poured quickly and run from end 

 to end of the mold while pouring, or poured 

 in a broad stream. The best results are 

 obtained by heating the lead in a heavy 

 ladle from which it may be poured ; but in 

 case a thin pan is used, the metal should be 

 heated again for pouring after it has been 

 melted. The illustration shows the lead 

 already poured. 



It will now be possible to take away the 

 movable plates from the fixed. Hang the 

 parts between the jaws of a vise after the 

 head of the machine screw has been sawed 

 off, and the pieces of fiber and nut removed, 

 using the machine screw as a support and 

 lightly tapping both ends of the fixed 

 plates simultaneously with a U-shaped 

 metal or wooden bridge and a hammer. 

 Considerable care should be taken not to 

 warp the rotary plates by uneven ham- 

 mering. 



Having separated the plates it will be 

 found a simple matter to remove the card- 

 board washers, either by shaking them out 

 or picking them out with a pin or needle. 



All of the plates should have their edges 

 gone over with a fine nail file to remove any 

 rough spots or burrs caused by sawing. 

 The lead castings on the movable plates 

 should be touched up also. Both ends of 

 these castings should be filed down about 

 1/64 in. All this should be done with 

 great care. 



The two fiber pieces, which are to be 

 used in pouring the center lead supports on 

 both sets of rotary plates, can now be 

 sawed in half, thus making four pieces in 

 all, oblong in shape. These should be 

 split with a saw for a distance of ^-in. from 

 one end, making a i/i6-in. cut, which should 

 run parallel to the largest faces of the 

 fiber. The pieces may next be bolted to 

 the brass plates with the small machine 

 screws, after the putty has been removed 

 from the countersunk holes. The heads of 



