<HTML>Anthony wrote:
>Archae:
_snip>
>The fork would have two quartz crystals, one attached to each
>prong. This (obviously heavily) reinforced quartz double
>drill bit would be pushed down as it was rotated. The
>downward force might have forced the two prongs TOGETHER,
>instead of APART... creating the conical shape we see in the
>Petrie artifact.
Such a tool would not be very efficient... to minimise the amount of work in coring one needs to have the thinnest cutting surface with the max surface area. Otherwise more rock would need to be removed and more revolutions of the drill would be needed for the same result. As well, efficient lapidary cutting requires abrasive with sharp edges (it is these sharp edges that do most of the cutting)... once they are worn off it is just smooth surfaces grinding against each other, this will work but not as well. New abrasive grains are needed or else more work is needed to cut rock by abrasion. Anyway, a lot of the core holes have the reminates of the core broken off at the bottom, the ring left by the cutting tool is consistent with a very thin walled tool, and the core-holes are either tapered with max diameter at top, producing a V-shaped notch with he core, or are parallel sided. Stocks (2001) core is tapered and this is found to be the result of wobbling of the coring-bit due to the reciprocal motion of the bow, and movement of the bow to different sides of the drill by the workers as they changed position around the work area.
>Now, when I say "upside down" , I didn't mean the block was
>upside down... I meant our orientation of the "rough" end was
>actually where the drilling BEGAN... not where it ended and
>was broke off. Why would they bother finishing off and
>smoothing this end if it was to be discarded, anyway?
The smoothing is probably an effect of the cutting process. It is more likely that they were using the core, the core hole, and the tailing for other special purposes, since this was an expensive procedure and any waste would very inefficient.
_snip>
>Isn't it just as likely that it was a table leg? Could it
>not have been turned on the ancient equivelant of a lathe,
>creating the helical lines?
I would expect that if any lathe or pole-lathe existed in ancient Egypt they were very simple (adaptation of the potter's wheel or bow drill) and only used as a finishing tool. It would be very unlikely that the object called Granite Core #7 would have been produced on a lathe.
>Even if it WERE a core sample,
>maybe it was being ground down for another use. We don't
> know. Trying to invent technologies to match ONE piece of
>evidence seems a little extraneous... are there more samples
>than just the Petrie core?
yes... many examples of coring and boring of rock in AE:
a) Marks on the well-known anorthositic gniess statue of Khafre (4th Dynasty, Lucas & Harris 1962).
b) Marks on the sarcophagus in the King's chamber of the Great Pyramid (4th Dynasty)
<a href="[
www.sunship.com] 1 </a><a href="[
www.sunship.com] 2 </a><a href="[
www.sunship.com] 3 </a><a href="[
www.sunship.com] 4 </a>
c) Marks on an travertine (alabaster) statue of Menkaure' (4th Dynasty, Reisner 1931).
d) Marks on an unfinished statue of Menkaure' (4th Dynasty, Reisner 1931)
e) Bore holes for metal pegs in granite at the pyramid temple of Menkaure' (4th Dynasty, Petrie & Griffith 1888).
f) Sockets in the granite of the pyramid temple of Menkaure' for the ends of door-posts, and for bolts (4th Dynasty, Reisner 1931).
g) Marks of coring drills are found on a block from the complex of Neuserre (5th Dynasty, Borchardt 1907), with traces of verdigris from the copper of the drill (Reisner 1931).
h) Marks of four different coring bits of various diameters in the eye sockets of a statue in granite (12th Dynasty, Borchardt 1911-1936).
i) Marks in the eye sockets of a granite head, probably of Middle Kingdon date (Borchardt 1911-1936).
j) Marks on an obsidian head of Thutmose III from Karnak (18th Dynasty, Lucas & Harris 1962).
k) Marks on granite sarcophigus with coring holes in lid peg socket (21st dynasty)
<a href="[
www.pbs.org] </a><a href="[
www.pbs.org];
l) Core-hole from a Ramesside granite door jamb with a stump of the drill core remaining at its bottom from Asasif (Arnold 1991).
m) Petrie gives many additional examples of core holes and cores (Petrie 1883; 1917). Drawing #7 Granite drill core found at Gizeh
<a href="[
www.users.net2000.com.au] href="[
www.gizapower.com]; Chris Dunn's examination </a>
Drawing #8 Part of a cast of a pivot hole lintel from a granite temple at Gizeh. In this example the core is not be entirely broken out, and remains to a length of 20 mm.
<a href="[
www.users.net2000.com.au];
Drawing #9 Tavertine (alabaster) mortar found at Kom Ahmar, broken in course of manufacture, showing the core in place.
<a href="[
www.users.net2000.com.au];
Drawing #10 A small travertine (alabaster) core found with others at Memphis.
<a href="[
www.users.net2000.com.au];
Drawing #11 A marble eye made for inlaying, with two core holes made with thin coring bits, one within the other.
<a href="[
www.users.net2000.com.au];
Drawing #12 Part of the side of a drill-hole in diorite exhibiting regular grooves from Gizeh.
<a href="[
www.users.net2000.com.au];
Drawing #13, A limestone fragment from Gizeh, showing how closely holes were placed together to remove material by coring.
<a href="[
www.users.net2000.com.au];
Core-holes 45 cm in diameter found on a dressed platform of limestone (Petrie, 1883)
Petrie (1977) also states that many stone vessels contain a circular groove on the inside bottom the, coring hole used in the initial stages of hollowing similar to modren stone vessel manufactoring (Can narrow-necked stone vessels be made today?)
<a href="[
www.geocities.com];
An example of a partially completed granite bowl on display in the Cairo Museum, demonstrating the use of the coring drill to more quickly remove waste rocks in the manufactoring of stone vessels.
<a href="[
www.sunship.com];
<a href="[
www.sunship.com];
As well Lucas and Harris (1962) give examples of drilling with copper or stone points, where the drill holes are still clearly visible, for example:
a) Marks on two pieces of inscribed stone vases of diorite and dolomitic limestone, from the step pyramid at Saqqara (3rd Dynasty)
b) Marks on a diorite bowl of Khaba (3rd Dynasty, Arkel 1958)
c) The nostrils, ears and corners of the mouth of an alabaster statue of Menkaure' (4th Dynasty, Reisner 1931)
d) Limestone block with 10 boring sockets from the mastaba of Perneb at Saqqara (Arnold 1991). The holes are randomly distributed over the top of the block's surface with some slightly overlapping at the edges. This may represent an underlying block used to bore completely through a number of rock object that rested on top of it, or possibly a waste piece of rock used to practice bowl or other stone vessel boring skills.
Coring holes found at the pyramid temple of Sahure in Abusir
<a href=" [
www.bssw.de];
>If none exist, then maybe we are
>studying one little anomalous piece of data, which actually
> has NOTHING to do with the way it was drilled.
The cores and core-holes are striated in other examples, they seem to be horizontal in some cases, spiraling in others, or possibly both. The spiraling striation have an observed max length of about 60-50 cm (most observed are less than this), which is constant with stroke length of a bow that would be used to power a lapidary coring drill (Stocks (2001). i.e. a max of 4 discontinuous turns on a 4.5 to 5 cm diameter core as originally described by Petrie (1883) for core #7. The striations are observed to be discontinuous, variable depth, and variable in distance between the turns. Since the core is tapered, it is clear that grinding is occurring on the upper walls of the core so one would expect there to be striations there. As pointed out by Stocks (2001) this is due to the wobbling of the drill due to the reciprocal motion of the bow.
Archae Solenhofen (solenhofen@hotmail.com)</HTML>
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