Spa filter adapter 1.5" BSP to 1.75" SAE (reversed)

thingiverse

I may be the only person who needed this. But if this helps one other person, I will be happy. (Updated 4/10/2023 - The first version I uploaded somehow flipped the thread on the coarse thread - fixed it now so it should be correct) This adapter takes a spa filter with the fine thread 1.5" BSP threading and converts it to the coarse threaded 1.75" SAE style (As used in PWW50P3 filters). I accidentally bought $200 of the wrong type of filter and didn't realize I had done until it was too late to return. These sit about an inch taller with the adapter in but still fit in our spa filter cabinet. To use, screw on tightly to the filter then screw the filter and adapter into the spa itself. Threading is tighter on the filter than the spa by design, but I added notches to assist in removing should it get stuck on either the hot tub or filter.