This is a spare that I created after a tripod fell over and broke the fluted central bar at the top. The spare makes use of a M6 x 75mm bolt and a M6 to M10 Ferrule, plus a M10 x 25mm washer at the top and M6 x 12mm washer at the bottom. Once fitted it is a solid connection and the bolt precludes the possibility of the print breaking a spilling a camera. The fluted part slips into the housing without any issues, it is shorter but if you need it longer and can print it let me know and I will send the file. I printed using PETG but the trial part was just as good in PLA.