The gas lift cylinder in my office chair fell apart (the rod protruded out of the bottom of the chair) because of a defective plastic piece in the thrust bearing that was supposed to allow the chair to swivel. Rather than order a whole new gas cylinder online, I simply 3D printed a stronger replacement part since all of the other components were still in good shape. In most chairs, this bearing is under the removable, non-pressurized cover of the gas lift cylinder, making DIY repair easy and safe.