Basically, you
- take out the trim router
- replace it with a spindle of the same diameter, to reuse the router mount (800W is enough and they come in 65mm diameter models like the router). They come in two types: air-cooled and water-cooled. Water-cooled is quieter, but does involve adding a water cooling pump & hoses to the setup.
- the spindle’s “power supply” is called a VFD and is a somewhat bulky box that one adds.
- the VFD needs to be connected to one of the signals (PWM) available at the Shapeoko controller connectors, and its parameters tuned.
The other advantage of a VFD+spindle setup is that you can then control the RPM automatically from the Shapeoko controller, no need for adjusting the RPM manually at the router (admittedly, this is not a big deal, but as with all comfort features, one soon cannot do without them)
Anyway, you should not start upfront with a spindle upgrade, I just mentioned it as one of the ways to eventually end up with a quieter setup. My wife could not bear the sound of the trim router at 30.000RPM, so I got a green light for the upgrade easily.
There are a couple of threads here from people who use their Shapeoko in an enclosure in their living room, @holgersindbaek is one of them so out of curiosity you can check out his setup here.