This section is from the book "The Boy Mechanic Vol. 2 1000 Things for Boys to Do", by Popular Mechanics Co.. Also available from Amazon: The Boy Mechanic, Vol2: 1000 Things for Boys to Do.
As I desired to print only a portion of some of my 5 by 7-in. plates on post cards and the part wanted was near the edge of the plate, I cut out the printing frame, as shown at A in the sketch, to accommodate that part of the card I reserved for a margin. This permitted the card to be placed in the frame without making a bend. - Contributed by J- H. Maysilles, Rochelle. Ill.
Ill: Slots Cut in the Frame to Receive the Post Cards without Bending Them