Helical Bending
16 x4x1/2 rectangular tube curved the easy way to a 7ft 8in inside radius (inside stringer) and an 11ft 10in inside radius (outside stringer). Walk up turn right. 30.92 degree pitch.
Pipe bending for circular stair stringer.
Bar bending of helical strakes.
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"Helical spiral bending" can be done with virtually every structural steel section as well as with plate. Actually, spiral bending most accurately refers to curved steel that has the shape of a hose coiled flat on the ground or the shape of the heating coil of a cooking range. The resultant coils are sometimes called "pancake coils." Examples of this type of steel bending can be found in our section on Multi-Radius Bending and our Circular Staircase Gallery.
True helical steel bending is also called "pitched rolling" or "sloped rolling." Helical rolling is commonly used for curved steel stair stringers, curved steel stair handrails, and helical transfer conveyors. Stringer members are checked for radius, pitch and plumb for ease of fabrication. As an alternative to true helixes, handrails can be rolled to an approximate flat radius for a lower price but may require field fitting.
Helical Bending Capacities
Chicago Metal Rolled products has some of the largest capacity and greatest experience in the steel bending of helical forms. The company can form the most challenging helixes from the smallest to the largest sizes of plate (3" x 60"), channel (C18 x 54.7), tube (18" x 6"), pipe (24"), or beam (W30 x 99). Turn around times are about 1-1/2 to 2 weeks.
Helical Bending Value-Added Services
In addition to forming helixes, we can also punch holes for stair pans allowing easy installation in the field. Other drilling, punching, welding, cutting can be done to the steel sections either before or after the bending operations.
Helical Bending Applications
Circular staircases are found in both residential and commercial construction adding grace and appeal not only to the architecture but to the experience of the visitors who walk up and down them. Chicago Metal has rolled stringers for high-end retail stores like Barneys, for palatial mansions, for the Tribune McCormick Freedom Museum inside Chicago's Tribune Tower (In plan, the curve is elliptical.), and for more mundane applications like the stairs around a large storage tank.
Another industrial application includes helical strakes which are commonly used as stiffeners and wind deflectors on stacks.
Contact us for more information on helical bending.
