--Contributed by Wm. R. Ingham, Rosemont, Arizona.
** Cutting Circular Holes in Thin Sheet Metal [35]
In arts and crafts work, occasion often arises to cut a perfectly
circular hole in sheet copper or brass. To saw and file it out
takes time and skill. Holes up to 3 in. in diameter can be cut
quickly and accurately with an ordinary expansive bit.
Fasten the sheet metal to a block of wood with handscrews or a
vise. Punch a hole, with a nail set or punch, in the center of the
circle to be cut, large enough to receive the spur of the
expansive bit. A few turns of the brace will cut out the circle
and leave a smooth edge.
--Contributed by James T. Gaffney, Chicago.
** Key Card for Writing Unreadable Post Cards [35]
A key card for use in correspondence on postals that makes the
matter unreadable unless the recipient has a duplicate key card is
made as follows: Rule two cards the size of postal, one for the
sender and one for the receiver, dividing them into quarters.
These quarters are subsequently divided into any convenient number
of rectangular parts-six in this case.
These parts are numbered from one to six in each quarter beginning
at the outside corners and following in the same order in each
quarter.
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