How are bike frames brushed finish?

Bike frames are typically given a brushed finish through a process that involves sanding or polishing the surface with a fine abrasive material. This technique creates a series of uniform, parallel lines that enhance the aesthetic appeal while also helping to hide scratches and imperfections. The process can be done manually or with machines, and is often followed by a cleaning step to remove any debris. Finally, a protective coating may be applied to maintain the finish and prevent oxidation.