This was made by a library patron yesterday. The print came out beautifully. Below is the follow up for use by the patron.
The controllers fit perfectly into the print. Really perfect.
"A 1.5 inch PVC pipe is nearly right, but seems about 2mm too wide. A 1.25 inch PVC pipe is too small. The actual diameter of the base is 35.5 mm. Looking at the instructions I see that the creator used a 40mm outer diameter pipe with an inner diameter of 36.4mm. So I'm thinking the creator is outside the US where everyone uses metric. I couldn't find a pipe of any kind that would be a good fit (i.e no metric pipe in the US) We went to the hardware store and found a FERNCO 1056-150 flexible coupling with ring clamps. We tightened it down on the print base and also accommodate a pipe 1.5 or 1.25 inch PVC pipe - or a metal vacuum attachment extender which is what we used.
I would recommend that anyone in the US make an adjustment to the base, either bigger to be 37mm diameter for a 1.5 inch PVC or shrink it to 30.75mm if they want a 1.25 inch PVC."