Ian,

Please don't think I have ever doubted your intelligence, Ian. If anyone can recognize intelligence, I can. I have a great respect for intelligence. I sometimes wish I could exercise more of it myself. (And I'm still smarting over the invitation to leave my local Mensa group so that I didn't dilute the gene pool.) ;<)

I understand you are not a trained engineer, though, from what you wrote in your previous posts, I didn't realize that you understood that feeding while rotating was necessary to achieve cutting when drilling. A simple misunderstanding on my part, I'm sure.

Your statement, "you have now amended your explanation of the supposed spiral grooves to suggest that the feedrate was "greater" rather than "faster", and that you do not think the drill bit was rotating rapidly (whichever method was used)," totally misrepresents my position. I have not amended my original thinking on the subject of feedrate or what I intended to say. I have rephrased my explanation not amended it. I never did think that the drill was rotating rapidly, and if you would go back and read chapter four in The Giza Power Plant: Technologies of Ancient Egypt, you will find that what you describe as a recent amendment, was, in fact, rephrased and published over a year ago.

With respect to the rest of your post, I am happy to respond with my report on my research at the Petrie Museum University College London.