Snips

 

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Tin Snips are often used for manually cutting ductwork.  Tin Snips come in three different styles: straight, left offset and right offset.  Straight tin snips usually have a yellow handle and are used to cut down and across a profile.  Straight tin snips are not typically used for cutting straight along an edge. 

Offset tin snips are used for cutting straight along an edge.  Left offset tin snips have a red handle and can cut an edge profile to the right allowing the snips to cut along it on the left side of the offset.  Right offset tin snips have a green handle and can cut along an edgewhere the profile is to the left allowing the snips to cut along it on the right side of the offset.  Most jobs that require manually cutting ductwork use a combination of the three tools to complete the job.