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Nice! This is great!
I left 0.2" thickness, or approx 5mm of wood remaining. 0.3mm is very thin and I would be very concerned about accidentally damaging the surface of the desk. Consider using an alternate charger, with a greater charging distance like the one I showed in my guide. Hot glue isn't as nice as a threaded solution like the Evoline, but it still works!
You set the depth of cut for CNC router, or adjust the router depth for a handheld electric router. I did this in step 4, I used a 0.8" depth of cut for the 1" thick slab of wood to leave 0.2" remaining.
You could do this with a handheld electric router, instead of a CNC router. Electric routers can be purchased at Home Depot, Lowes, etc.
I'm not sure. My guess is that any chargers following the Qi wireless charging standard would have similar distance/range. Select a wireless charger that matches or exceeds the wattage supported for wireless charging your phone. For example, if the iPhone 8 supports 7.5W charging over wireless charging, be sure to purchase a 7.5W or greater wireless charger.
You could try something like this for a DIY router:https://lifehacker.com/use-a-chisel-to-make-a-handheld-woodworking-router-1732957767
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