Woolf Aircraft stocks elbows in various materials, bend radius, angles and thickness. Materials used are stainless grades 304, 316 and 321, aluminum types 6061, 5052, and 3003, and 1010 steel. The actual bend dies we have determine the bend radius. Normally they are a multiple of the outside tube diameter. They are referred to as 1D (one times the outside diameter), 2D or 3D. Standard radius is 2D, tight radii are 1 to 1-1/2D and wide radii are 3D or more.
Elbows are stocked in 45°, 90°, 120° and 180° of bend. 180's are the hardest to produce and have the greatest wall thinning because of the distance stretched around the bend. Our standard thickness is 16 gauge (.065"). Other walls available are 20 gauge (.035") 18 gauge (.049") and 14 gauge (.083"). Standard elbows usually have 6" straight leg lengths.
Remember to allow for thinning in the bend. The stretching of the material during bending causes the outside of the bend to become thinner, while the inside can become thicker. This is due to the natural flow of material.