Gauge
A sheet metal gauge (sometimes spelled "gage") indicates the standard thickness of sheet metal for a specific material. The thickness of sheet metal is indicated by a series of numbers, which is called as gauge. As the gauge number increases, the material thickness decreases.
Cutting the sheet along curved lines
The bent snips are used to cut the inside curved lines and for trimming curved edges.
To lock the grooved seam
Hand Groover: The hand groover is made up of cast steel and is used to make external locked grooved joint.
A groove is made at the bottom of this tool to the required width and depth. This has a handle in square or hexagonal shape like chisel to hold. This whole part is hardened and tempered.
The hand groover is specified according to the size of the groove of the groover.
Hard wood
Mallet is a shaping tool used for general purpose work like flattening, bending and forming to required shape of sheet metal. Mallets are made of hard wood.
When using any metal hammer for flattening the sheet metal, the face of the hammer may damage or leave impression on the sheet more than what is required for the job. To avoid such damage and a impression, mallets are used.
Malleable and ductile
Ductility It is a property of a material enabling it to be drawn into wires.
Malleability It is a property of a material enabling it to be drawn into thin sheets.