Now the the pen has been rounded a bit you can start on finishing the barrels up. I start with the top one. To achieve the smooth finish on the acrylic necessary for a scratch-free finish, you will need to know how to bevel a skew chisel to make fine sheering cuts. The video I made shows the proper method for making these cuts. Hold the tool so it has a substantial amount of support. Then touch the bevel to the work-piece and lean it into the material and begin shearing off fine shavings. A tennon is also cut (to accept the center-ring) using a parting tool and the sizing ring (the largest of the bushings). When the sizing ring fits over the tennon snugly that means the center-ring will fit well too. The rest of the Barrel is shaved down until it's just about flush with the sizing ring. Remember not to make this too close of a fit since sanding needs to be done.