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.
The modern stationary washtubs are box-shaped, with one side set at an outward angle or slope. The washboard, when used in these tubs, will slide up and down against the sloping part of the tub while the clothes are rubbed against them. This annoying trouble can be avoided by tacking, on the top edge of the board, strips of rubber cut from a discarded bicycle tire, placing the rubber side out. The friction of the rubber prevents any motion of the board. - Contributed by Jas. A. Hart, Philadelphia, Pa.