During machine it was noticed that the wet lay up has, as large as 1mm, eccentricity. Even when the alignment jig was used to center the 3D printed plugs in line. Hence, up to 2mm extra outer diameter needed to be laminated so any eccentricity can be removed during the final machining stage. A stepped 5:1 Von Karman shape was machined on the lathe using a parting tool and approximately 130+ 3mm-steps. This rough shape was sanded smooth to the final dimensions. Although the 130+ steps were a bit time consuming it went quite easily with excellent tolerances. An epoxy sanding coat of 24gr epoxy, 2gr glass bubbles, 0,4gr aerosol was applied and again sanded smooth on the lathe. After the final sanding the coupler diameter was machined according to the required outer diameter and the last step was to cut the tip of with the parting tool. The CNC machined aluminium nose cone tip was outsourced.
Notes: the aluminium nose cone tip design could have used a shorter shoulder and deeper thread for easier securing the nose cone bulkhead & electronics sled into the nose cone.