If you need to fabricate an exhaust header or intake system with tight bends, these 360 degree donuts are an excellent way to start. Just cut the donut into whatever angles you need and weld the tubing pieces into the desired shape.* The mild steel construction is economical and easy to weld.
Sizes 1.5" through 2.12" are constructed of 16 gauge tubing. Sizes 2.25" and 2.5" through 5" are 14 gauge. Size 2.37" is 20 gauge.
The bend radius is measured at the centerline of the tubing. Multiply the tubing OD by 3 to find the donut OD. The donut ID equals the tubing OD.
* Note: The inner seam (along the inside edge of the bend) is not welded at the factory. You must weld it closed after you cut the donut to the desired angles.