Seaming pliers fall into two basic categories, those with straight handles/jaws or those with bent handles/jaws. Within these are three more categories which are: corner, mini and interchangeable blade seaming pliers.
Straight seaming pliers
Straight seaming pliers are useful for pre-bending sheet metal at ground level before taking it up on to the roof. Their design helps to ensure that there is less pressure on the wrist when working in this position.
Bent seaming pliers
Seaming pliers which have bent jaws or handles are also known as cranked, angled or offset seaming pliers. For easier bending of sheet metal, a greater cranked angle will give more leverage.
Bent jaws/handles are useful for bending metal that is above head height.
45 degree angles vs. 90 degree angle
Bent seaming pliers have either a 45 degree angled blade….
….or a 90 degree angled blade.
The greater the angle of the seaming pliers, the more leverage is possible, so when bending metal to a greater angle you would choose the 90 degree angled seaming pliers.
Corner seaming pliers
To form a seam on a corner of sheet metal or to bend metal at a corner, you could use corner seaming pliers. Using standard seaming pliers for this task is possible but it would be awkward for beginners or occasional users, who don’t have the practice folding metal.
Corner seaming pliers are a specialised tool designed with slightly rounded edges to the blades, which allows the pliers to easily fit into corners or bend metal through an angle to make a corner.
Piccolo seaming pliers
Piccolo (small) or mini seaming pliers, which are so-called because their dimensions are smaller than any other seaming pliers, are designed for small scale, precise seaming and folding work in tight spaces where room to manoeuvre is limited.
Straight piccolo seaming pliers weigh 220g (0.48 pounds), the width of their jaws can vary from 20mm (0.78 inches) to 24mm (0.94 inches), the insertion depth is a maximum of 28mm (1.10 inches) and their length is usually between 185mm (7.28 inches) to 250mm (9.84 inches).
Bent piccolo seaming pliers also weigh 220g (0.48 pounds), their jaw width is 20mm (0.78 inches), the insertion depth is a maximum of 28mm (1.10 inches) and their length is from 185mm (7.28 inches) to 250mm (9.84 inches).
Piccolo bent seaming pliers can be used for accurate seaming and folding of metal, including above head height.
Piccolo seaming pliers are lighter, shorter in length, jaw width and insertion depth than the regular sized seaming pliers.
Interchangeable blade seaming pliers
There are seaming pliers made and available to purchase in the USA, which have interchangeable blades for increased versatility.