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Bond, A. Russell

"The Scientific American Boy The Camp at Willow Clump Island"

At the top
was a board whose lower edge lay flush with the edge of the door when it
was closed. For the combination lock we used a couple of spools, each with
one head cut off and the central hole plugged up with a stick of wood. In
the door and the top board of the frame, holes were drilled just large
enough for the shanks of the spools to fit snugly in them. Next we made a
trip to a hardware store for a file and a couple of large copper washers,
about 1-1/4 inches in diameter. The washers were fastened to the inner
ends of the spools after they had been pushed through the hole. The washer
on the door came just to the edge of the door, while the other extended
below the door frame and lapped under the door washer. Then in the edge of
the washer on the frame a notch was filed, while in the other washer two
notches were filed, so as to leave a tooth which fitted snugly into the
notch of the first washer (see Figs. 188, 189). The door was locked by
turning both the washers until the notch and tooth came in line with each
other, then pushing the tooth through the notch, and turning the washers
so that the frame washer hooked over the door washer. Then the door could
be opened only when the tooth and notch were brought in line.


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