The shape of today’s truss plates was greatly influenced by their little-understood production processes. While these processes involve proprietary methods, their underlying technology was conceived decades ago in the tool and die shops and the punch press plants across America, and both businesses were well equipped to supply prospective truss plate manufacturers. Even though fashioning the teeth of a connector plate required some unique craftsmanship, the resulting machine tools didn’t differ significantly from those that stamped other metal parts. However, the configuration of the truss plate design has determined the complexity of the tooling, the tonnage of the punch press, and the level of capital investment required. [For all images, See PDF or View in Full Issue.]
This is not to say that stamping truss plates was a straightforward process, especially for this industry’s founders. Yet, by necessity and almost by coincidence, each had an advantageous background that aided them in developing the plate designs that would undergird their new businesses. Carol Sanford tapped into the resources available in Akron, OH, the industrial town where he came of age. Cal Jureit benefitted from what he had learned working in a tool and die shop while waiting to be accepted into the U.S. Navy. Walter Moehlenpah used his mechanical engineering savvy to gain guidance from the many suppliers to the metal stamping industry that were near his St. Louis, MO location. And Edgar Mort of Inter-Lock Steel was already stamping nail-on plates when nearby truss plants made inquiries. But each of these founders produced markedly different designs when they embarked on truss plate development.
Not surprisingly, these plate designs were not chosen because they were easy to manufacture. Sanford experimented with multiple design variations and simply took the first one that met the requirements of the Miami, FL building department. It so happened that his Gri-P-late teeth could be formed with minimal force by a single stroke of a rudimentary punch press. Jureit’s long nail-like projections needed to be stiffer, requiring nearly twice the thickness of Sanford’s steel and double the required punching force. In addition, Jureit’s Gang-Nail contained three times as many teeth, resulting in at least a six-fold increase in the punching force. Moehlenpah’s complex tooth shape, chosen primarily to circumvent Jureit’s patent, couldn’t be formed in a single stroke of the press, necessitating a costly progressive forming technique. And Mort, with his more experienced eye, and likely in concert with Jack Ritter from Youngstown (OH) State University, chose a design that would perform consistently at all angles with respect to the wood grain, rendering his design even more challenging to stamp than the others.
While Moehlenpah succeeded in breaking Jureit’s patent, the resulting plate design, like Mort’s, was difficult to manufacture. Jureit also was stuck with a tenuous design that used twice the thickness of steel and cost twice as much per square inch as Sanford’s Gri-P-late. For more than a decade, however, when truss plates were in high demand, the extra cost and complexity weren’t crucial factors. Even so, Sanford began developing new plate designs in 1960, right after both Gang-Nail and Ronel patented plates that didn’t require supplemental nails, with these changes leading to a design breakthrough that resounds to this day.
In 1958, Carol Sanford hired Bill McAlpine as his chief engineer and put him in charge of new plate development. In 1965, McAlpine submitted a patent application for a breakthrough design in which two teeth project from the same slot. In 1966, when he and Charlie Harnden left to form Alpine Engineered Products, they simplified that plate design and contracted with a local stamping plant to produce their first plates. As a direct result, Alpine, the upstart in the industry, quickly began selling a plate with a considerable cost advantage, and that put Gang-Nail’s large following of fabricators at risk.
While McAlpine was innovating at Sanford Truss, Jureit was following suit, producing an 18-gauge plate and a much faster punch press to help lower his production costs. In 1966, Moehlenpah responded by introducing a 20-gauge plate, while retaining his much more intricately fashioned 16- and 18-gauge plates. Unfortunately, the teeth of his 20-gauge plate often bent over when pressed in Southern Pine and had lower values than the Alpine plate. For both Gang-Nail and Hydro-Air, these new plates proved to be merely stop-gap measures, because these plates had lower values than Alpine’s and they both continued to entail the higher operating and maintenance costs associated with their oversized punch presses and more complicated tooling. By the early 1970s, when Alpine decided to stamp their own plates, they were able to acquire the Sanford punch presses that had been sitting idle as Carol Sanford was winding down his business, furthering Alpine’s competitive advantage and accelerating their growth in market share.
Alpine’s lower manufacturing costs also enabled them to launch five new stamping plants in strategic locations across the country in the 1970s, with a much lower capital cost than their competitors would face. When I visited one of these facilities, I saw modestly priced 50-ton open back inclinable (OBI) punch presses that cost less than half that of Hydro-Air’s 100-ton Minster straight-sided presses.
Alpine compounded their advantage by installing engineering offices at their new stamping plants throughout the 1970s, further pressuring their competitors to respond. Moreover, the Alpine plate could be vertically pressed or rolled, unlike most of their competitor’s products, widening their appeal. As a result, nearly all of their competitors responded with similar plates during this period. Truswal acquired the nearly identical Ronel plate by purchasing Ronel, Hydro-Air’s Larry Beineke developed the PT plate, and Gang-Nail’s Carlos Rionda trumpeted the GNA plate. By the 1980s, all of these developments brought an end to the era of significant manufacturing advantages garnered from individual plate designs.