Years ago I created DIY kits on my own as a classroom set for STEM. I’m doing this again at a new school, and can’t find the store where I purchased, specifically, the coupler / adapter for connecting propellers to standard bilge replacement motors. Ideally, I would buy a kit of the couplers and propellers to keep things easy.
My question is - what is the best coupler/adapter out there now? There was an old aluminum one that I used to buy and would not stay on well. The newest one they offered was more reliable. Links please, and thank you!