Here we go again . . . MK4

[routercnc]

Awesome looking build!

Is that a piece of granite worktop you are using to measure flatness from?

It’s a marble plate from our old fire surround. I checked it against other ground surfaces and it is pretty flat at least down to 0.05 mm. Also a ground block placed on it starts to wring together like gauge blocks so it must be close to flat.
Obviously nothing like a grade A plate or AA plate but it was free.

I keep looking at the proper granite blocks for metrology but they are pricey . . . One day maybe