Shampoo Bottle Coupler

Pump-style product bottles are convenient in the shower, but if you throw them out when the pump dries up, you find there's a lot still left in there. Unfortunately, transferring that to the next bottle is a pretty big pain in the butt. Enter this simple coupler / mini-funnel which you can screw onto the donor bottle, and then invert that into the receiving bottle. Note that you may want to wait a week before doing this operation— depending how much is left over, a brand new bottle could be too full to be topped up without overflowing.

The thread on here is for Aussie brand bottles, and I'm not sure how universal the parameters are, but for this use case it's 33mm OD, 30.3mm ID, and a pitch of 4.3mm. The design was created in Fusion 360, with credit to Kwerkshop for the guide on how to combine the coil and sweep tools to create a thread with a custom profile: https://www.youtube.com/watch?v=AZ-Xi_uuCN8

Print this as oriented in the data files, with the threaded part down. No support