One end goes in the bushing, the other is tapered. In the middle is a flange. I'm not planning on painting the taper.
I'm thinking used ones bought cheap. Mine is a 2 hp/6 gallons. 165 liters/minute. That's 5.8 CFM. Three of those running on separate phases should give a pretty ok CFM at least.
2.5 year-olds have all kinds of phases they go thru but reading a little more of what you posted makes me think she is not being understood right.