The goal of this project was to increase the concentricity of a 35ft steel turntable. The center of the turntable formerly wandered approximately 6mm. After the installation of my upgraded bearing housing design and high precision rail system, the turntable has a concentricity of 0.25mm, halving the required specification of 0.5mm.

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The previous lateral bearing package made use of a solid mounting base. When shored up against the former rail system, the turntable would bind. This was due to the rail have poor circularity. My assessment of the system pushed the design towards a compliant, but reliable and more accurate system. I redesigned the rail system to a much higher tolerance and outsourced it construction, allowing for a more concentrated effort on the bearing package.

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This bearing housing design makes use of a flexible 4-bar mechanism, requiring no maintenance. The design has reliable kinematics and allows for a precise spring rate. Multiple bearings around the perimeter of the turntable allow for a strong resistance to global deviation of the turntable, while the spring rate of one housing allows for small local deviations in the rail.