Talk:Lithic reduction

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There seems to be a little controversy over due to their preternatural sharpness. vs due to their extreme sharpness. For my 2 cents, neither is quite there. These glass's sharpness is not preternatural, it's just that they are much harder than surgical stainless steel - and can support a thinner edge. They are also much more brittle than steels - hence their lack of general use.

I would like to see some evidence of surgical use. Modern ceramics (such as stabilised zirconium or silicon nitride) are capable of holding even finer edges than natural glasses (such as obsidian) or crystals (such as quartz). I doubt many institutes that would require a better edge than 440 Stainless steel (standard surgical) would use obsidian over a synthetic ceramic. There is also the question of mounting the blade in a sterile manner.

See this abstract for a study done on steel vs. obsidian scalpel blades. As for mounting in a sterile manner, you could use a screw-down clamp and replaceable obsidian flake inserts, or you could just injection mold thermoplastic handles around the base of a flake. Not sure how they do it in practice, maybe I can find a manufacturer/retailer who has a picture. scot 21:53, 13 December 2006 (UTC)

Bingo: these are made with the obsideian set into a maple handle, which is then coated in epoxy, allowing it to be autoclaved. And since re-sharpening is not practical, they'd be disposable anyway... scot 21:57, 13 December 2006 (UTC)

Here is a surgeon who uses them numerous times before discarding them. scot 22:51, 13 December 2006 (UTC)

1982 article on first modern consideration of obsidian blades for surgery; this article claims "infinitely sharper" than steel, I'm looking for a source with real numbers, since I see everything from 5x to 500x "sharper than steel". This gives a 3 Angstrom size for the obsidian edge, but nothing for steel. scot 22:56, 13 December 2006 (UTC)

I have therefore removed the following: Occasionally, obsidian flakes are used for delicate surgery instead of steel blades, due to their preternatural sharpness.

I also have a problem with the line: Flakes are often quite sharp, with distal edges only a few millimeters thick

One millimetre is very blunt. A surgically fine edge would be measured in micrometres - usually less than 10! I have left this intact, but would like some clarification.

That should be "molecules thick". scot 21:53, 13 December 2006 (UTC)

Yours, -Cataclysm.

---I think it is best for potential uses of lithics to be discussed in another section than lithic reduction, my main concern with this page is the level of technical jargon will limit who can understand the content. See my comments for pressure flaking. I won't touch this article unless I get some agreement on how to simplify the explanation. ZenTrowel 5/21/06

Merger

I completed the merger of the material from pressure flaking to this page. I also took some material from flintknapper as well, and will work on fleshing out this article. The merger tag has been removed, as well -- Oaxaca dan 14:46, 20 February 2007 (UTC)

Blades

I removed the reference to blade production being an innovation springing from the development of pressure flaking. This is simply not the case. The term blade in lithic studies has a very specific use. It generally refers only to blades struck from a prismatic core. This technique, while it did indeed represent a huge advance in the efficient use of stone, does not require pressure flaking. Sharp edged cutting tools (which may or may not have been retouched using pressure flaking are generally referred to as knives. In the near future, I think I'll expand the Percussion Flaking section to include references to prismatic blade manufacture and other prepared core techniques. But now, I'm going to sleep. Apmahd 09:39, 26 February 2007 (UTC)

I absolutely agree with the removal - I inserted much of that material from the flintknapping page because it seemed appropriate here, and meant to revise it, but it kinda fell through the cracks. However, concerning prismatic blade production - while I agree that prismatic blade production is not completed with pressure flaking per se, I think i would argue that the production of prismatic blades still utilizes a pressure reduction technique, not a percussive one. Blades are produced through the direct pushing of force through the material via some implement, not by striking it a la percussion reduction.

Perhaps we could have a sub-section under pressure flaking, or make it more neutral and change the main header to "Pressure Reduction" with pressure flaking and blade production being sub-sections... what do you think? --Oaxaca dan 19:48, 26 February 2007 (UTC)

Mmmm, thinking hard about this it seems to me that classifying blade production might be a bit of a challenge within this article. Most examples of blade production I've seen perform, have involved the use of indirect percussion, i.e. detaching the blade by striking a punch, rather than striking the core itself. Such a case would certainly still be considered a percussive technique. On the other hand, there's also the case of the "chest punch", where the knapper holds the core between his/her feet and presses his upper body weight down onto the core using a long punch. This type of reduction would, I suppose be consider a pressure reduction technique. Of course, there's never really been any firm archaeological evidence that this was a common technique among those who actually practiced by peoples employing lithic tech as part of their economies (note: after originally writing this, I found that Molinia quote of your Obsidian Use in Mesoamerica article. That's almost as good as archeological evidenceto me!). That said, I see no reason why techniques used by recreational knappers than could theoretically have been used in the past should not be included in this article.

As for the switch to Pressure Reduction, I'd advocate sticking with Pressure Flaking, simply because it's certainly the more common term in the literature. The format I've been thinking of would include major headings for Percussion Flaking and Pressure Flaking (including the chest punch technique), and sub-headings within Percussion Flaking for hard-hammer, soft-hammer, and indirect techniques, very similar the the current structure in flintknapper. I think once we get this page up to snuff, it'll be time to merge the two anyway. In any case, I'm glad to be collaborating on this and look forward helping build this section up. There's a lot to do! Apmahd 07:35, 27 February 2007 (UTC)

ahh, very interesting - I think its a testament to perhaps our different academic backgrounds, but I hadn't heard of blade production via striking a punch - as a meso guy, my whole conceptualization of the process involved the chest-punch techique (or one very similar to it). Anyway, i agree with you on the organization - lets see what we can do with this. -- Oaxaca dan 14:30, 27 February 2007 (UTC)

Very much so. Most of my experience is in the western Canadian Plateau and Subarctic, and the the people I've learnt pretty much everything about lithic tech from also worked either in the same regions or on European Palaeolithic stuff. The general assumption in such parts is that folks wouldn't have wanted to bother carrying big chest punches around with them. Anyway, I'm gonna actually start writing up some of this bad boy today, it think. Right after I finish this Arabic assignment . . . Apmahd 08:52, 1 March 2007 (UTC)

OK, so I made the first major changes, seperating and revising the hard-hammer and soft-hammer sections. Next will come indirect percussion and a revision of the pressure flaking section, plus expansions of all sections. Anyway, let me know what you think of these changes. Apmahd 12:40, 3 March 2007 (UTC)

right on - looking good. I've done a little clean up, and will try to add content in a little bit. I'll wait and see what you do, and then maybe add some descriptions of the pris. blade production process as an example of an alternative way direct pressure reduction can be used (i.e., its not all flakes and bifacial thinning!) Peace -- Oaxaca dan 16:07, 3 March 2007 (UTC)

Heat-based knapping

Back in the 1960s one of the teachers in my high school (Kamloops, BC) was an amateur archaeologist and had done some work he was proud of on flint technique. Heat the stone then touch it with a wet brush or reed; the sudden cooling causes contraction and removes a flake. He claimed this gives much better control than percussion or pressure.

Also, in many cases it works better than grinding the stone so it calls the whole paleolithic/neolithic distinction based on chipping vs grinding into question, in particular the notion that some tribes are "more advanced" than others based on this. He thought he had proved something interesting about some tribes using this. Unfortunately, it was a long time ago & I do not recall which tribes, but he was mainly interested in Western tribes — Northwest coast, interior BC, Alaska, Navaho, Hopi, ... — not prairie or eastern Indians or Inuit.

Is this method a known option? Is there anything to his theories? Pashley (talk) 17:29, 23 January 2014 (UTC)

Lithic core

When I follow the link in the 1st paragraph to "lithic core," I learn that it's the rock portion left after the tool/s have been removed from the original stone. But this article implies that the core is equivalent to a lump of unworked tool stone.

The articles need to be brought into conformity, but I don't have the expertise to do so. Thanks to whomever else can take this on. KC 20:27, 30 March 2016 (UTC) — Preceding unsigned comment added by Boydstra (talk • contribs)