Anyone have any concrete grinding tips?

[volvolugnut]

It blows my mind that the Great Pyramid was once finished in fine white limestone... no jagged stair steps/blocks showing.

What blowing everybody's mind on the Egyptian cores is. They measured the concentric cut lines on the cores. The feed rate works out to 0.100 inch per revolution of the drill.

Drilling granite with a modern diamond drill rotating at 900 revolutions per minute, penetrate rate is 1 inch in 5 minutes. This works out to 0.0002 inch per revolution. 0.100 / 0.0002 = 500. Meaning that the ancient Egyptians were able to cut granite at a feed rate 500 times greater then we do today.

Please don't try convincing me they had help from ET.

Pure speculation on my part: They used a consumable column of granite weighted for extreme contact pressure. This column was rotated by slave labor at slow rate. Both the bore and column were crushed and ground at the point of contact. A smaller pilot bore could be used to catch the cuttings and periodically cleaned out. This assumes a vertical bore hole.
This is similar to oil field drilling method where a heavily weighted drill bit is rotated and grinds away the material to make the hole. In oil field drilling, a thick mud carries away the cuttings back to the surface.
volvolugnut

[RickHaleParker]

Pure speculation on my part: They used a consumable column of granite weighted for extreme contact pressure. This column was rotated by slave labor at slow rate. Both the bore and column were crushed and ground at the point of contact. A smaller pilot bore could be used to catch the cuttings and periodically cleaned out. This assumes a vertical bore hole.
This is similar to oil field drilling method where a heavily weighted drill bit is rotated and grinds away the material to make the hole. In oil field drilling, a thick mud carries away the cuttings back to the surface.
volvolugnut

Here a theory with a chemical solution that fits the evidence. If you cannot make a better tool, make the material easier to cut ..Ingenious.