I feel sure that this must have been asked before but please forgive me if it has. Being new to segmented turning I am going through the learning curve that I am sure all of the experienced turners have been through. In this case figuring out the best way to consistently flatten rings on both sides and so both side are parallel to each other. There are many fairly easy ways to flatten one side but the other side can be a challenge. I have experimented somewhat both on and off the lathe but can't say that I am particularly happy with anything one appraoch right now. I would be most grateful for experienced suggestions. A drum sander would be perfect but I have neither the space nor the funds for that.