THE ORIGINAL NUT
If one rummages through the drawers of vintage tools in Clarence Marshall’s shop in the carriage house, they may find one or more sizes of the tool pictured below. These tools found frequent use in the 19th century and into the 20th century and might have been used to maintain a Stanley steam car, or any number of pieces of equipment or buildings around the property. The items pictured would have found definite use in Marshall Brothers paper mill. This tool, made of cast iron, could be purchased in 1/16” increments from 5/16” to 11/16” size and were also available in sizes 3/4” to 1-1/4” by 1/8” increments. What were these tools used for?
Answer
The items pictured are known as Square Brace Wrenches. They are used for running-on and then snugging-up square nuts, which preceded the hex nut we use today. Today’s equivalent might be a socket used to tighten hexagonal nuts with ratchet drive.
The first threaded fasteners for holding two items together but allowing them to be separated, if necessary, were made of wood from before the time of Christ. Carefully handmade, a wooden nut and threaded dowel can apply hundreds of pounds of force to hold a connection of two or more items together. Eventually with the discovery of iron, threaded fasteners were produced with increased strength and durability. Today wooden nuts and bolts are decorative items often made by woodworkers to display their craftsmanship.
With the building of water powered iron rolling mills such as that at Wooddale, it was possible to roll a uniform sheet of cast iron. The sheet was next punched of holes on a fixed grid while hot using waterwheel or steam power. The next step was to shear the sheet into strips of evenly spaced holes. Each strip had the internal surface of each hole along the strip cut with threads. Finally, the strip was sheared between each threaded hole to make individual square nuts. Iron plate was also cut into square sizes and run through a series of rollers to make the square profile into a round rod. Cut to length a square head was hammered into one end of the rod to match the nut that would be added later. Threads were then cut on the opposite end for form a bolt.
Square nuts, and bolts made of iron were the first metal fasteners and machines were soon developed to make the fasteners economically in large quantity. Also made were screws with square heads called lag screws. These were designed to be driven into wood timbers to hold them together or to hold iron pieces to wood.
Where there was a quantity of nuts requiring ‘running onto’ their bolts, or a quantity of square-head lag screws to be installed, the square brace wrench allowed such to be done quickly and efficiently. The wrench was locked into the chuck of a hand brace (pictured). The wrench was then placed over a nut at the end of it’s bolt or screw, and the brace cranked to turn the nut down tight on the bolt. Alternately the square brace wrench fitted to the square head of a lag screw could see the lag screw driven into the lumber. As a lot of torque could not be applied to the nut or lag screw, a wrench was used to tighten the nut or screw to the required tightness.