Two bearing-based spool holder

I went to the store to buy bearings and they had no 608s and I could only get 2 609s. So I decided to design a whole new filament spool holder around a pair of 609 bearings.

Unlike many other designs, the base is printed as a single upright print. The spool is centred using pyramidal endcaps held together with a central threaded bar - this ensures good alignment with the centre for arbitrarily-sized spool holes.

In addition to the parts printed here, you will/may need 2x 609 bearings.