The file 'Ashford Jumbo Bobbin Core With 6.6mm Hole 3D Printer Model' is (stl) file type, size is 116.2KB.
Thanks to HackManiac for creating and uploading the original design. As originally stated, the core must be drilled out with a 6.5mm drill bit after printing.
This remix avoids that step by resizing the inner dimension to 6.6mm which should be enough clearance for printing. This should hopefully mean you can print this core without any additional processing.
In addition, I have taken inspiration from vivvi75 and included a leader yarn hole in the design.
Ashford_Jumbo_Core_6.6mm.stl | 273.6KB |