Helical rolling, also known as pitched rolling or sloped rolling is one of the more complex processes that bender/roller companies might incorporate into their rolling services. Helical rolling is typically used for curved stair stringers, curved hand rails and helical transfer conveyers. With the increasing advances in bending and rolling machinery, the potential range of radii and pitch dimensions that can be managed for steel members has grown exponentially.
Specifically, we can take a look at how a bender/roller might work with helically curved handrails. Architects design stairways with many different styles of handrail in mind. These range from simple flat bar and tubing to more decorative pieces with more complex cross-sections. For a simple handrail project, such as curved pipe handrails used with helical tank staircases, the finished project may be powder-coated. In this case, small blemishes or distortion might not be an issue. However, when curving decorative pieces operators must often use a special rolling set up to prevent distortion or blemishes to the material. Taking in to account the end needs of the customer product is quite important.
Knowing what a customer’s finished product must look like is one important step for a project estimator. Among the other important steps would be making sure to correctly account for the material needed for rolling. Project drawings often will indicate the chord length of a rolled piece, but this is a straight measurement, and would be shorter than needed for a helical segment. In these early stages of the rolling process, project estimators must solve multiple calculations to give the exact dimensions to the machine operators in order to form these helical railings. Estimators must know the equation for the circumference of a circle, and the Pythagorean Theorem. For a handy reference in figuring out the calculations necessary to estimate the length of a helical curve, you can refer back to our blog from June 4th of this year.