
This leaves so much out.. The tube they’re using is 1/4 inch thick, the tool mark left on your example is mm thick. The sand theory also doesn’t explain flinders Patrie’s core, the penetration rate shown is from high speed rotation and huge amounts of pressure on the bit to bite that deep. Also doesn’t address how they carved the ring out on the inside of the slab.
No hate but the devil is in the details here.
English


















