ar 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. Cut out one rectangle of each number with a sharp knife,
distributing them over the whole card. Then put a prominent figure
1 at the top of one side, 2 at the bottom and 3 and 4 on the other
side. The numbering and the cutouts are

[Illustration: The Key Card]

shown in Fig. 1. The two key cards are made alike.

The key card is used by placing it over a postal with the figure 1
at the top and writing in the spaces from left to right as usual,
Fig. 3, then put 2 at the top, Fig. 4, and proceed as before, then
3 as in Fig. 5, and 4 as in Fig. 6. The result will be a jumble of
words as shown in Fig. 2, which cannot be read to make any sense
except by use of a key card.
--Contributed by W.J. Morey, Chicago.

** Homemade Carpenter's Vise [36]

The sketch shows an easily made, quick-working wood vise that has
proved very satisfactory. The usual screw is replaced by an open
bar held on one end by a wedge-shaped block,

[Illustration: Vise Made Entirely of Wood]

and the excess taken up on the other end by an eccentric lever.
The wedge is worked by a string passing through the top of the
bench and should be weighted on the other end to facilitate the
automatic downward movement.

The capacity of the vise, of course, depends on the size and shape
of the wedge-shaped