How to Lay Out Sheet Metal

Sheet metal is used for gutters, flashing, shelving and a number of smaller projects. A thin sheet of metal is easy to inscribe and cut by hand, making it useful for hobby metalworkers and in school shop classes. Before cutting, workers lay out the project on the metal by inscribing it with sharp tools and straightedges. You can lay out simple sheet metal projects using blueprints and standard tools such as a combination square, a prick punch and dividers.

Instructions

Examine the blueprints for the project you'll lay out on the sheet metal. Make note of how much sheet metal you'll need. Sketch a possible placement for the project pieces on another piece of paper or on the metal itself, using a pencil.

Measure the exact placement and size of each piece on the sheet metal project using a ruler or measuring tape. Use a flat steel square or combination square, respectively, for parallel lines and right angles. Use a pencil compass to mark circles and curves.

Mark the bending points for pieces you will fold into three dimensional shapes, using a pencil and a ruler.

Punch points into the metal where lines intersect, begin or will serve as the centers of circles. Press the point of the prick punch on the intersection and lightly tap the handle end of the punch to mark the sheet metal. The lighter the tap, the more accurate the mark.

Inscribe the project layout on the sheet metal using a scratch awl and straightedge. Mark these lines on top of the pencil lines.

Set the straightedge on a pencil line marking one of the project pieces. Place the pointed tip of the awl as close to the straightedge as possible and pull it along the straightedge to mark a line into the metal over the pencil line. Press the pointed tip of the awl lightly against the metal when inscribing lines; a little pressure goes a long way.

Inscribe circles with a pair of dividers, which are similar to a compass but have metal tips instead of a pencil. Set one point of the divider in the center of the circle marked out in pencil. Set the other end on the curve line. Press down lightly and draw the point along the curve to inscribe a line.

Repeat the process with all of the pencil-marked lines on the sheet metal. You are now ready to cut out the sheet metal project.