Editing Metal shaping

Metal shaping is an invaluable skill to have in hot rod fabrication. There are many specialized tools used in the forming process. Shaping metal is basically as simple as shinking or stretching it to achieve the required shape. Shrinking metal can be done using a stump and wooden or plastic mallet. A set of tucking forks can also be used but this process can be slow and tedious. A reciprocating machine such as a Pullmax with thumbnail dies can also be used to shrink metal rapidly. This is not a machine for a novice though. Learning to shrink metal by hand is said to be the best way to see how it reacts throughout the process. In the photo below is a "stump" made from pieces of maple hardwood glued together and then different sized cone shaped cutouts made. [[Image:DSC05346_(Small).JPG]] Stretching metal can be done on a shot bag with a wooden, plastic or steel mallet. The bag is made of leather and filled with a material such as lead shot or sand. Plastic injection molding pellets have been used for this as well. Metal may also be stretched over a hollow such as the cut out of a stump or even a piece of pipe. In the photo above, one corner of the stump has a 3" dia hole for stretching metal. Shrinking a piece of metal around the edges will result in a bowl like shape. After shrinking the edges to the maximum amount allowed by this process, it then becomes necessary to stretch the center area of the piece to achieve the radius required. Stretching the edges of a panel only and not working the center at all will achieve the classic potato chip shape. This is called the reverse curve. The streching can be done by holding the edge of the sheet over a cutout in a stump and applying some severe hammer blows. The photo below shows a wooden mallet with a small radius and a panel that has been stretched over the 3" dia cut out. [[Image:DSC00394_%28Small%29.JPG]] The photo below shows both edges of the panel after alot of stretching over the hole on the stump. The edges of the panel were held half over the hole and the edge of the sheet driven into the hole for stretch also. [[Image:DSC00400_%28Small%29.JPG]] An English wheel (ewheel) can then be used to smooth out the lumps created from the stretching or shrinking processes. If too much pressure is exerted by the ewheel on areas that were shrunk, the material will start to stretch changing the shape. If too much pressure is exerted at the stretched areas, the metal will be stretched even more and change the shape. Pic of ewheel below. This is a clone based on the Imeperial Wheeling Machines brand. [[Image:IMG_3072_(Medium).jpg]] The photo below shows the same panel after more stretching followed by rolling it thru the ewheel to smooth out the lumps. [[Image:DSC00409_%28Small%29.JPG]] HAMMER FORMS A hammer form is usually two pcs of wood or other materials used to sandwich a piece of metal in order to bend it to shape. Body filler and cement can also be used. These materials can be used for a complex shape. In the pics below, high density polyethylene sheet was used along with a 1/8" thick steel plate. This panel could have been done on the bead roller but was done with a hammer form for a more accurate shape. The plate was used to achieve a nice defined edge. [[Image:IMG_3413_(Medium).jpg]] The steel plate was used to mark out the blank on the sheet. [[Image:IMG_3414_(Medium).jpg]] The top piece of plastic is cut on an angle to allow for hammer clearance. The pieces in the pic below are arranged in the order in which they will be bolted together. [[Image:IMG_3416_(Medium).jpg]] [[Image:IMG_3417_%28Medium%29.jpg]] The hammer blows in the pic below are directed almost straight into the material with a slight downward trajectory. Tapping the edge into itself allows the material to shrink. This was done all the way around the sheet. [[Image:IMG_3418_%28Medium%29.jpg]] [[Image:IMG_3423_%28Medium%29.jpg]] The piece came out a little deformed as the edges on this piece were bent at different angles and shrunk at different amounts. The hand shrinker/stretcher are good for adjusting these edges. [[Image:IMG_3425_%28Medium%29.jpg]] [[Image:IMG_3428_%28Medium%29.jpg]] The slapper and post dolly were used to flatten out the curled edges. [[Image:IMG_3426_%28Medium%29.jpg]] The finished panel sitting in place on the car. [[Image:IMG_3385_%28Medium%29.jpg]]

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