Tin snips

Snips, also known as shears, are hand tools used to cut sheet metal and other tough webs. There are two broad categories: tinner's snips, which are similar to common scissors, and compound-action snips, which use a compound leverage handle system to increase the mechanical advantage.

Tinner's snips, also known as tinner snips or tin snips, are one of the most popular type of snips. They are defined by their long handles and short blades. They usually have extra wide jaws and are made of drop forged carbon steel. Depending on the size of the blade, tin snips can cut between 24 and 16 gauge cold rolled low-carbon tin. They can be ranged in length from 7 to 14 in (180 to 360 mm) long. There are two main types: straight-pattern and duckbill-pattern. Straight-pattern are best for straight cuts, but can handle gentle curves. Duckbill-pattern snips, also known as trojan-pattern snips, have blades that taper down from the pivot to the tip of the blades. The blade edges are also bevelled to more easily cut curves and circles or shapes. They are a lighter duty snip that can only cut up to 25 gauge mild steel.

Other common blade patterns include the circle pattern or curved pattern and the hawk's-bill pattern. Circle pattern snips have a curved blade and are used to cut circles. Hawk's-bill snips are used to cut small radii on the inside and outside of a circle. The shape of the blades allow for sharp turns without buckling the sheet metal. A common use is cutting holes in pipes.

Compound-action snips are also known as aviation snips because they were developed to cut aluminum in the construction of aircraft. They can handle aluminium up to 18 gauge, mild steel up to 24 gauge or stainless steel up to 26 gauge. These type of snips have become the most popular because of the linkage that increases the mechanical advantage without increasing the length of the snips. There are three cutting styles: straight cutting, left cutting, and right cutting. Straight cutting snips (generally have yellow colored soft grips) cut in a straight line and wide curves; left cutting snips (usually red) will cut straight and in a tight curve to the left; right cutting snips (usually green) will cut straight and in a tight curve to the right. These different cutting styles are necessary because metal is stiff and heavy and does not move out of the way readily when cutting around a curve. The respective styles move the material out of the way when cutting in the direction they are designed for. The blades are usually serrated to prevent material slippage.

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Wikipedia