If you want to impress the sh!t out of them...

Download FreeCad. Then design what you need to make. Be as precise a humanly possible. Then export the design in .stl format.

Present them with a challenge. Arguing that they likely aren't as precise as what you can buy online. When they jump at the challenge, pass them the .stl file and ask if they can CNC it.

I'm not going to say that I've used this method with our 3D printer guru. (He was very happy to do it - great guy)

But I'm not going to say I didn't.

Say hello to my dust protector on my semi-automatic water reservoir filler for my espresso maker.

Walking the 15 feet to refill the water tank was taking up far too much time. 😀. Never again.