Forging

The Fire
The Anvil
The Hammer
Basic Techniques
Other Equipment

The first few sessions are spent orienting students to the forge space, equipment, safety, and basic blacksmithing techniques. MIT's blacksmithing lab contains three coal forges and six anvils, a coal bin, storage for tools, stock, and finished pieces, and a cutoff wheel and wire brush tool for finishing. It shares space with the MIT Glass Lab.

The Fire

To light the forge, place a ball of newspaper in the fire pot, light it, turn on the blower, and cover with coal. Take care not to smother the flames, and/or make sure the airflow is sufficient. As the coal heats up, it will start to offgas. The exhaust should be taken up by the hood, not released into the room, as it contains sulfur dioxide and other hazardous materials. Too much airflow tends to blow the fumes away from the exhaust and into the room. Eventually, flames should start poking through the coal bed. From here, you can add more coal, rearrange the coals, and turn the airflow up or down to build a fire of the desired size and temperature.

^ Back to top

The Anvil

The anvils are mounted on heavy stands, to raise them up to a comfortable level and provide extra stability. Each anvil has a curved horn, which can be used to guide curves and widen holes; a flat top, for creating flat faces and bending angles; and a hardy hole for holding various accessories.

For forming a curve in two dimensions at once, this form is useful. A hardy (cut off tool) is helpful for making notches or cutting off a piece. To create smaller-scale holes, this hardy horn can be used. When an extra hand is needed to hold a punch or other tool, the hold-fast can be hammered into the pritchel hole to keep the workpiece steady.

^ Back to top

The Hammer

Once the fire is hot, it's time to hammer. Which hammer to use depends on the project. In general, hammers should be light enough that you can swing them easily and with sufficient control for a few hours at a stretch. Some smiths grip with their thumbs pointed along the handle, others prefer to keep it out of the way. When hot metal is hammered, metal flows out from the point of impact, so the shape of the hammer head affects the shape of the deformation created in the workpiece.

This cross-peen hammer has a round face at one end, to spread evenly in all directions, and a blunt wedge (peen) on the other, to lengthen the metal in one dimension only. The straight-peen is similar, but the wedge is parallel to the handle, rather than perpendicular. This hammer has two different peen widths on its head, to confine the impact to a smaller or larger area as needed. This ball-peen hammer has a flat face and a hemispherical peen, to allow simultaneous isotropic spreading in the plane and curving up out of the plane.

Hammers with wood or bronze heads are used when force needs to be applied without deforming the metal surface. The soft faces are therefore deformed instead. They should be used with a soft surface, like a wooden block.

^ Back to top

Basic Techniques

To demonstrate how metal acts, a chunk of clay is drawn and pointed. First, square up the faces by laying it on the anvil flat and hammering, then rotate 90° and repeat until all the faces are flat. To draw a taper, hammer starting from a few inches from the end, all the way to the end of the piece. To maintain a constant width, turn it 90° periodically, making sure to square up the sides when they show irregularities. To make a point, tilt the piece up to half the desired angle, so the anvil and hammer faces act on both sides at once. Here, the clay has a taper on one end and a scroll on the other. Tapers can be formed in two directions, by flipping the piece 90 degrees every so often. Students were allowed to experiment with the clay before picking out pieces of metal to start practicing with.

After drawing a taper, bending it into a corner or scroll is a common next step. Here, the edge of the anvil is used to put a start the bend. After another heat, the piece is hammered back onto itself. If the end needs to be tucked in tightly, the edge of the anvil can be used as a fulcrum. If not, the edge can be used to put a series of sharp bends in the metal. After the spiral has started, it can be rolled up as far as desired.

^ Back to top

Other Equipment

Many accessories have developed to make blacksmithing easier and safer. All students are required to wear safety goggles, closed-toed shoes, and have no dangling clothing or hair. Tongs and/or leather gloves help grip small workpieces. To put twists in square or bar stock, heat the piece in the area to be twisted, then brace it in a press. Apply the S-curve above the heated area and twist evenly but quickly. Stop when the metal is noticeably cooled.

Punches come in a variety of shapes and sizes, and can be used to create surface detail as well as punching holes. The tip is hardened and tempered while the body and head are left soft to withstand force without shattering.

A wire brush removes iron oxide (scale) and other debris from the workpiece before it goes back into the fire. The wire brush wheel is useful for removing iron oxide from finished pieces, for a cleaner surface finish. One way to cut metal to length, either before or after forging one end, is with a hacksaw.

^ Back to top