To machine the fin can, we use a mill in Todd's shop, with the rotary indexer holding the tube at particular angles. We then brought our own carbide endmill to cut through the carbon fiber fin can in Therion (2016), because carbon fiber quickly dulls endmills.
For Raziel (2017), we needed a 48" fin can (the tube containing the motors and fins); however, Todd's tailstock for the mill could only hold a 24" tube for machining. To hold such a part, we designed a jig that would hold the middle of a tube. The jig consisted of a saddle that was adjustable in the X, Y and Z directions, and held down the part with a steel strap. Additionally, we inserted MDF disks into the tube to hold the tube round near the saddle and near the chuck; the MDF disks are sacrificial, because milling the endmill would cut through the MDF.
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