Tools for fabricating sheet metal have been around as long as sheet metal itself. Sheet metal and sheet metal machines and tools were used to make a variety of things, including furnaces, ducts, hot water heaters and automobiles. The functions of these tools are to cut, shape, bend and assemble. New sheet metal tools can be very sophisticated, such as hydraulic-powered, robotic, computer-aided spot-welders. Vintage versions of the essential tools, although simpler in form, can achieve most of the same results.
Many heavy, vintage tools were belt-powered and used a clutch. This system of transmitting power decoupled the machines and transmission from the actual power source. A shop only needed to find some source of torque to turn a belt. A water wheel, steam engine, electric motor or even a donkey could power them. Lighter sheet metal machines, like English wheels and hand tools, used old-fashioned muscle power.
A break press or brake is a large, industrial sheet metal fabrication machine used to bend sheet metal. They are still used today, though now they are often computer assisted and have more sophisticated power and control mechanisms. Breaks were often used to bend straight, 45-degree angles in sheet metals as would be seen in square duct work. They can also be used to bend more delicate folds used to form joints. Die stamps are very similar, but instead of bending a simple fold into sheet metal, a piece of sheet metal is pressed or "stamped" with tons of force into a die. This is the technique used to create production automobile fenders and bodywork.
Shears and Punches
Shears and punches use extreme pressure to form sheet metal. Only, instead of folding, bending or stretching sheet metal, they cut it. Similar to a paper cutter, a shear cuts a straight line in sheet metal. A punch uses the same idea but instead of shearing the sheet metal with two straight metal edges, like a cookie cutter. There is a table with the desired shape and a press with the corresponding, inverse shape. The press shears the sheet metal into the shape of the die. They may be used to punch out holes or create "blanks" or flat cutouts which are then inserted into a die to gain their form.
English Wheel/Planishing Hammer/Bead Rollers
An English wheel is a tool used to form complex curves in sheet metal. The operator places a piece of sheet metal between two hard wheels and rolls the material back and forth. With skill, the pressure of the wheels, can create a wide variety of forms. Bead rollers are similar in that that they use wheels to create forms in sheet metal, but they press a "bead" into the perimeter of a piece of sheet metal to give it more structural rigidity. Planishing hammers also use a similar concept, but they use the continual and repetitive striking of the material to shape it. Planishing hammers are similar to the block-and-dolly technique, only the tool is stationary and the work moves, instead of the work being stationary and the tools moving. Vintage planishing hammers are automated, often with the common belt/clutch system.
Spot Welder / Rivet Guns
Spot welders require electricity to make a contact weld. Sometimes spot welders are used to create finished, structural welds; other times they are used as assembly aids to hold work in place until additional fastening can be achieved. A common mechanical fastener for sheet metal is the rivet, applied with a rivet gun. Rivet guns use force to make their connections and were often used in the aircraft industry.
Hand Tools: Snips, Files, Hand Shears, Seamer/Sheet Metal Pliers
Hand tools were critical sheet metal tools. From simple snips and hand shears to files and deburring tools, and hand-seamers or metal pliers, these were the tools to handle the final fit and finish of sheet metal work. They are still common in sheet metal work, today, in spite of technological advances.