[Bonetools] For Idola Grau and everybody else

[François Poplin]

April, 23rd

When I wrote these lines (01/04/2013) :

/The cord is pulled towards 6 h. If it were attached with a knot around 
the bit, it would pull the bit directly and entirely in that direction. 
As the action is tangential (which gives the rotating movement), this 
pulling towards 6 is only partial, and the turning action gives a 
certain pulling effect towards the left ; the resultant being a pulling 
towards "down left on the watch", let us say towards 7 h for example. 
That drifft/lee-way will ovalize in that way the bit housing,/

I had /a priori/ in mind the action/pressure of the rope on the quarter 
0 - 3 hours. Experimentation has shown since (I don't remember when I 
sent this) a force rather towards 5 h (considered form the top, which 
isjust the contrary of underneath the bit-cover). That shows the 
resultant of pressures extending/developping further than 0 hour, on the 
preceeding hours ("piezzocentre" is about at 11 hours), eventually "all 
around the clock", even on several loopings - one has to think to what 
occurs when we want to brake a rope by coiling it around a tree. The 
mechanical problem becomes a friction one, and the experimenting has to 
be extended to different adherences (by rubing the rope on colophan for 
a better adherence for instance or, to the contrary, on paraffin or 
soap). [Should be considered too another variable : the diameter of the 
bobbin (coil ? reel ? etc.) on which the cord acts.]

Leaving the bones for a while, I would like to draw attention to the 
shift/deflection(/deflexion)/drift when boring/drilling long channels, 
such as in a stone crocodile of a fontain in /villa hadriana/ I had to 
comment. The boring for a lead pipe was clearly done with sand and reed 
(which, being flexible, is appropriate, as in modern oil drillings). In 
order to avoid the shifting, one has to prevent the rubbing, therefore 
not to leave the drilling/rotating ax free, but to maintain it with some 
guide - possibly made of bone, even of a metapodial, which will wear the 
wear - and I come back here to an insolved problem which has been 
presented some months ago by a british colleague ; Christian Küchelmann, 
could you get it back out of your archives ? Maybe it will dry tears 
with wear.



-------- Message original --------
Sujet: 	A thing of beauty is a joy or fever
Date : 	Mon, 01 Apr 2013 12:03:15 +0200
De : 	François Poplin <poplin at mnhn.fr>
Pour : 	Mailing list for archaeologists of the research group for the 
study of object and waste of bone, antler. ivory and horn. 
<bonetools at listserv.niif.hu>

Preliminarily :

cord, rope, string ? I'll use /cord/ because of the vicinity with both 
french /corde/ and spanish /cordon/.

auger, bit, drill, trepan ? I'll use /bit/ because I need to 
point/specify the metallic rotating and active part/piece/axis/axle 
biting into the material (spanish /broca/).

And now :

suppose you are going to drill a hole, with the bit put on the material 
in left hand. The right hand coils up the cord clockwise, so as it is 
tangent/tangential at 3 h. You cover the bit with left hand and pull the 
cord. The drill turns clockwise. If you want to protect your left hand, 
you put a "bit-cap"/"bit-cover", and if you have to act in force, you 
call a second pair of man's hands grasping a cross-rung/cross-beam as 
bit-cap (1), giving a double handle as on a pneumatic tool/drill ; so as 
to "take the bull by the horns" (fr. tenir le taureau par les cornes, 
spanish : <I would like to know>).

The cord is pulled towards 6 h. If it were attached with a knot around 
the bit, it would pull the bit directly and entirely in that direction. 
As the action is tangential (which gives the rotating movement), this 
pulling towards 6 is only partial, and the turning action gives a 
certain pulling effect towards the left ; the resultant being a pulling 
towards "down left on the watch", let us say towards 7 h for example. 
That drifft/lee-way will ovalize in that way the bit housing - and now, 
you print and see trough from the back the page 89 of the paper send by 
Simon Davis, and you get it.

You have it elementarily with the distal hole fig. 36, and it goes on 
with the intermediate, where a symmetric effect brings the complement : 
that bone is technically reversible, both ends being roughly 
interchangeable in form. It was used equally with distal part or 
proximal part on the left, and when you turn the page upset down, the 
figure of holes does not change. (2)

When you have to cover the bit quickly (this work is long and time is 
money), it is useful to have not only a single hole/housing, but rather 
several, not to have to grope too much ; and to have not to choose 
"distal or proximal". With a certain acquaintance of the tool, you find 
your marks, and no matter the orientation of bone itself, the 
pertinent/relevan being to have it with a symmetric/reversible 
arrangement/adjustment. And the most visited and ovalized holes will be 
the closest to the grasping (left) hand, on the left, with the result 
that were (more) solicited distal and intermediate holes of the bone 
when grasped by distal end, and proximal and intermediate holes when 
grasped by the proximal end.

Or you prefer a single hole, and you get fig. 37, where the reversibilty 
distal/proximal gives thes same (cumulative) image than on the 
intermediate hole of fig. 36.

I that conception, either the cord was recoiled each time, or the left 
part of the cord left in the left hand was used for return back the cord 
for a new action clockwise. And we get here in touch with a considerable 
point of technical progress/history of technics : nowadays, all our bits 
are clockwise acting/working (or : would it be the contrary elsewere, as 
for car driving ?). Maybe theses bones show the invention/revolution of 
the "one way drilling" - at a time before brace, and waiting for it.

It would be for me the third occurrence of "bonebearing witness for iron".

(1) with a seating/housing/recess/socket for the head/upper end of the 
bit ; I did not want to make my sentence heavier.

(2) This may be surprising. But listen and watch : when you have a 
cord/rope/string with a certain twisting (S, for example, which is 
contrary of Z twisting), and when you make a looping/bight/hair pin with 
it, the two parallel parts show the same twisting.

Paris, the first of April 2013.

-- 
François POPLIN

Directeur honoraire de l'UMR 7209 Archéozoologie, Archébotanique : sociétés, pratiques et environnements

Responsable du Séminaire d'Anthropozoologie

Muséum national d'Histoire naturelle
CP 56
Ancien Laboratoire d'Anatomie comparée
55, rue de Buffon
75005 Paris
01 40 79 33 11
fax ------ 33 14

francoispoplin.blogspot.com

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