Hand grooving tools

The hand groover is used when making a seam joint by hand between two pieces of sheet metal. The end of the tool is recessed to fit over the joint formed when the edges of the two pieces of metal are prebent into a U-shape and interlocked. The grooving tool is then placed over the interlocked edges and hammered. One edge of the tool acts as a guide while the other forces the metal down into a crease,thus forming a groove. This crease or set in the metal should be made gradually,the tool being hammered while tilted very slightly in the direction in which the crease is to be made. This will avoid marking the metal on the opposite side of the joint to the crease. A tool a size larger than that of thegrooved joint should be chosen to give clearance in use. The tools are manufactured in various sizes from 1/8in to3/4 in (3–19mm). These grooved joints can be used to advantage when fastening large flat panels together as used on commercial vehicles.
Car Repair Talk's forum.