Understanding the Process of Rolling Tubing to Match a Curved Bar Face

When designing or fabricating a bar with a curved face, achieving a seamless aesthetic often means custom-bending tubing to follow that exact contour. This process—rolling tubing to match the curve—requires specialized techniques, materials, and attention to detail. Below is an overview of what’s involved, and why it’s more complex than it may initially seem.

Precision Rolling with Heavy Wall Tubing

To match the curve of a bar face accurately, metal tubing must be precisely rolled using specialized equipment. A critical factor in this process is the use of heavy wall tubing, typically with a wall thickness of .065", as opposed to the more common .050". The increased thickness serves a practical purpose: it helps minimize visible deformation during the rolling process. Lighter gauge tubing tends to buckle or distort, especially when bent along tight or compound curves.

Heavy wall tubing maintains a cleaner exterior shape and sturdier structural integrity, but it also introduces new challenges downstream.

Adjusted Radius for Accurate Alignment

Importantly, the curved tubing doesn’t simply match the exact curve of the bar face—it must follow that curve at a larger radius, offset by the centerline of the tubing based on the projection of the selected bracket. In other words, the tubing is not rolled to the same radius as the bar itself, but rather to a radius that is increased by the distance between the bar face and the center of the tubing, as determined by the bracket’s standoff. This ensures that the tubing follows the bar’s curve in parallel, maintaining proper alignment and visual symmetry.

Modified Fittings for a Flush Finish

One of the challenges of using heavy wall tubing is compatibility with standard flush fittings, such as domed or flat end caps. These components are generally designed for standard wall thicknesses, so when used with .065" tubing, they don’t fit properly out of the box. As a result, end caps and other flush fittings must be modified or machined to accommodate the slightly smaller inner diameter of the thicker tubing.

The "Oval Effect" and Reaming Brackets

Even with thicker tubing, the rolling process inevitably causes the round cross-section of the tube to become slightly oval-shaped—not enough to be visible to the eye, but enough to interfere with precision-fit components. This is particularly important for brackets, which are intended to slide snugly over the tubing.

To compensate for this, brackets are typically reamed out—carefully widened or adjusted—to allow them to slide over the tubing without force. This small but necessary step ensures both a clean installation and structural security.

Material Waste and Bending Setup

Another important aspect of the rolling process is material waste. The rolling equipment must grab the tubing at both ends during the bend, which requires excess material beyond the curved section. This clamping area cannot be used in the finished product and is typically cut off, leading to significant scrap loss. This is an unavoidable byproduct of rolling tubing with precision and control.

Segmented Tubing for Shipping

Lastly, when curved tubing is required in long lengths, shipping becomes a logistical and financial hurdle. Freight costs for oversized or unusually shaped packages can be exorbitant. To control these costs, it’s common practice to segment the tubing into shorter sections for shipping. These segments can then be joined onsite, often with internal splices or couplings, preserving both the aesthetic and functional integrity of the curve.

Conclusion

Rolling tubing to match a curved bar face is a complex process that balances material strength, fabrication tolerances, bracket geometry, and shipping logistics. The tubing must not only follow the bar's curve, but do so at an increased radius based on the bracket offset. Using heavy wall tubing helps retain the structural and visual quality of the curve, but it requires downstream adjustments to fittings and brackets. From invisible ovality to visible craftsmanship, every detail matters—and every curve tells a story of precision engineering behind the bar.