Page:Popular Science Monthly Volume 90.djvu/974

This page needs to be proofread.


��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


�^^^^^gk '^^^'^'^i;^^^^ ^,.,-'^'^ ^^

� �■Mil

�, s^^ipr

��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

�� �