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 necessity for using more than one cleat for fastening two boards together may be done away with by using the device shown in the sketch. The center cleat prevents the boards from buckling while the sides are tightly held by these simple flat fasteners. The fasteners are made of tin cut as indicated, slipped between the edges of the boards and the parts bent over and tacked. Where the strain is not too great the holders may be used without a cleat, making an effective flat fastening. - Contributed by W. O. Nettleton, Washington, D. C.
Ill: The Metal Clips Hold the Edges of the Boards Together Closely and Quite Rigidly