03/25/2026
Did you know there's a huge difference between being "planed smooth" and being truly flat?
These two photos show a great comparison. I processed a piece of cherry through a high-end industrial thickness planer. It feels smooth to the touch, but it's not truly flat.
Check out the photos:
In photo 1, I took a very shallow 0.50mm flattening pass with the CNC. Notice the dark spots of wood? Those are low areas that the CNC's surface planer didn't even touch. This proves how un-level the surface still was, even after coming out of a very expensive planer.
In photo 2, I took a slightly deeper pass of 0.75mm. This was just deep enough to reach the lowest spot, leaving the full face perfectly clean and, more importantly, perfectly flat.
This is exactly why I do my final flattening on the CNC. If you want a perfect, gap-free glue-up, especially with critical joinery, you can't beat the precision of a CNC for that final, truly flat surface.