Forty years ago, a frenetic fray raged over the World Record for truss production. While CMs across the country competed, the two main players, Littfin in Minnesota and Dickie Vail in Louisiana, produced numbers that may never be equaled. The massive trophy, displayed today in the lobby of Littfin Truss [See PDF or View in Full Issue], attests to the magnitude of their accomplishment.
Skeptics may claim that 2000 BF/man hour would only be possible with a simple fink truss. However, this characterization overlooks the great advantage of the now-mothballed multi-head vertical press: material flow.
Today’s dominant truss machine, the roller gantry, exhibits critical shortcomings:
- cut lumber is positioned far from its ultimate position in the jig
- to finish fabrication an additional process, a finish roller, is required
- to stack and band trusses yet another downstream process is necessary.
The multi-head system facilitates a single, continuous process to take trusses to completion. Cut parts may be located immediately adjacent to their final position in the jig. No piece of wood has to be moved more than a couple of feet, drastically less distance than a roller gantry. Since the speed moving material and the effort required to move it both depend on the distance traveled, the multi-head machine outmatches, by far, today’s roller gantries.
Thus, the “Secret” of the World Record is superior material handling. This explains why Carol Sanford’s 1960’s roller gantry patent included table frames with movable steel plates and not solid tables: so material could be placed closer to the jig. This lesson from 40 years ago should be a fundamental consideration in the design of truss machines of the future.