Background
The “truck bed” is the rear flat surface surrounded by bed front and side walls, and closed up at the end by the tailgate.
Conceived for work, pickup trucks began their evolution in the early 20th century as simple, inexpensive, easy to repair, and utilitarian vehicles designed to haul stuff. To save weight, expense, and enable easy repair, the bed steel frame was finished with planks of broad leaf Southern (Ford used Northern) yellow pine.
A GM truck pine plank bed treated with with a dull black coating
The wood was usually soaked in creosote to prevent fungus and treated with linseed oil/coal pitch giving the bed floor a dull black color. The planks were held in place by metal skid strips also painted black. By the mid-50s, wood planks were often painted in the truck’s body color but the finish remained rough. Needless to say, manufacturers did not pay attention to the wood bed appearance as a key selling feature.
The fan base of the classic 1959-87 El Camino together with restorers of vintage pickups began to re-think the humble wood bed with stunning results.
The outer edge of the groove on the planks must leave some lumber expansion room to the edge of the metal bed strip. In other words, given a half inch gap twixt planks, 2(C+D) + 1/2″> width of metal bed strip.