You snark, but please note the "[1983]" in the title. This article's points have since been expounded on, with new evidence both archaeological and experimental.
Namely:
> The concentric lines were not always perfectly parallel.
1. What the article calls "concentric circles" are, in fact, series of spirals. That is, a cutting point ploughing through the granite, round and round.
And indeed the fine abrasive circles that this article manages to reproduce (image 7b) look nothing like the original fairly well-spaced, deep-cut grooves of the original hole (image 1a, all the way at the top).
Petrie himself documented spiral grooves that span many drill rotations, sometimes totaling over 6 metres in a single continuous groove. This is well established and not disputed because the physical evidence is so plain.
Why the OP failed to mention spiral grooves and talks about "concentric circles" instead is unclear, given they otherwise quote Petrie extensively.
> [the hole] diameter on the outside is 5.3 cm. and tapers to 4.3 cm. on the inside.
> …a tubular copper drill creates a more parallel drill hole since it cannot wear beyond the internal diameter of the drill.
2. By all accounts, the tubular drills were fairly thin. We know this because there are thin (overdrilled) circles at the bottom of discovered tube holes, up to 0.5cm in thickness of the tube wall max. There you can see the actual narrow width of the tube because the bottom wasn't sawn off as in the case of OP's particular sarcophagus.
Again well documented by Petrie and others, supported by overwhelming physical evidence, so not a point of contention.
The OP does not go into how the observed difference of 1cm compares to the wear of the (presumably thinner) "internal diameter of the drill". See for example [0] for a clearer, updated exposition.
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To be clear, none of this is of course evidence for any "aliens". But reading your snark reminded me of those internet fly-by experts who deride honest work of others because "The science is settled bro, I saw a documentary on NBC! Aliens lol these other people are cretins!"
I'd recommend turning off sound if Youtube amateur commentary irks you, but the breadth of physical evidence (photos and videos of actual stone artefacts, not theories around them) they display is astounding. Reading scientific papers (or watching NBC…) alone won't build you enough intuition and nuance for fly-by snarks. It is a complex topic, and not all amateurs are cretins. A bit of humility helps.
I agree that they're misusing the word "concentric". However, I'd be very surprised if they truly overlooked the grooves being continuous spirals, as that would be extremely meaningful. Accepting your citation of Petrie, I'm actually surprised that the grooves were spirals, as that implies a cutter which makes significant progress in a single rotation, which seems unlikely in any stone, let alone granite.
Well yes, that's my point – the process is not trivial, with surprising technical details.
For a more in-depth take on grooves – at least more in-depth relative to "concentric circles" or Lehner's "wet sand" video) check out my link above, https://antropogenez.ru/drilling/. Specifically on Petrie's testimony they offer this:
> Of course, Petrie’s Core#7 does not bear any regular helices or a thread cut in granite with a fixed jewel point with a pitch of 2.0 mm, as it has been described by him. There is only a series of grooves, the formation mechanism of which is described above in detail. Their pitch, being very irregular, is not related to the advance movement of the tool cutting edge.
Most importantly, they ran actual experiments on actual stones.
And their theory for those grooves is a sort of emergent property of the accumulated effect of corundum grains falling into the same crest/trough pattern along the tube wall while drilling downward, leading to the observed series of (irregular) cut spiral grooves.
Namely:
> The concentric lines were not always perfectly parallel.
1. What the article calls "concentric circles" are, in fact, series of spirals. That is, a cutting point ploughing through the granite, round and round.
And indeed the fine abrasive circles that this article manages to reproduce (image 7b) look nothing like the original fairly well-spaced, deep-cut grooves of the original hole (image 1a, all the way at the top).
Petrie himself documented spiral grooves that span many drill rotations, sometimes totaling over 6 metres in a single continuous groove. This is well established and not disputed because the physical evidence is so plain.
Why the OP failed to mention spiral grooves and talks about "concentric circles" instead is unclear, given they otherwise quote Petrie extensively.
> [the hole] diameter on the outside is 5.3 cm. and tapers to 4.3 cm. on the inside.
> …a tubular copper drill creates a more parallel drill hole since it cannot wear beyond the internal diameter of the drill.
2. By all accounts, the tubular drills were fairly thin. We know this because there are thin (overdrilled) circles at the bottom of discovered tube holes, up to 0.5cm in thickness of the tube wall max. There you can see the actual narrow width of the tube because the bottom wasn't sawn off as in the case of OP's particular sarcophagus.
Again well documented by Petrie and others, supported by overwhelming physical evidence, so not a point of contention.
The OP does not go into how the observed difference of 1cm compares to the wear of the (presumably thinner) "internal diameter of the drill". See for example [0] for a clearer, updated exposition.
----
To be clear, none of this is of course evidence for any "aliens". But reading your snark reminded me of those internet fly-by experts who deride honest work of others because "The science is settled bro, I saw a documentary on NBC! Aliens lol these other people are cretins!"
I'd recommend turning off sound if Youtube amateur commentary irks you, but the breadth of physical evidence (photos and videos of actual stone artefacts, not theories around them) they display is astounding. Reading scientific papers (or watching NBC…) alone won't build you enough intuition and nuance for fly-by snarks. It is a complex topic, and not all amateurs are cretins. A bit of humility helps.
[0] https://antropogenez.ru/drilling/