Stone Tool Manufacture

Stone tools are made by removing material from a pebble or core until the desired shape of the core has been attained. The first flakes struck off (primary flakes) bear traces of the outer surface (cortex). Trimming flakes are then struck off to achieve the final shape, and certain edges may then be retouched by further removal of tiny secondary flakes.

Although the core is the main implement thus produced, the flakes themselves may well be used as knives, scrapers, etc. The toolmaker’s work will have varied in accordance with the type and amount of raw material available.

The History of Stone Tool TechnologyThe history of stone tool technology shows a sporadically increasing degree of refinement.

The first recognizable tools are simply choppers and flakes made by Knocking pieces off pebbles to obtain sharp edges. The best known examples are the so- called Oldowan tools from Olduvai Gorge, Tanzania.

After hundreds of thousands of years, people progressed to flaking both surfaces of tool, eventually producing the symmetrical Acheulian hand-axe shape, with its finely worked sharp edges.

The next improvement, around 100,000 years ago, came with the introduction of the Levalloise techniques named after a site in a Paris suburb where the core was knapped in such a way that large flakes of predetermined size and shape could be removed.

The next improvement, around 35,000 years ago, with the Upper Paleolithic period, blade technology became dominant in some parts of the world. Long, parallel-sided blades were systematically removed with a punched and hammer-stone from a cylindrical core.

This was a great advances, not only because it produced large numbers of blanks that could be further trimmed and retouched into a wide range of specialized tools (scrapers, burins, borers), but also because it was far less wasteful of the raw material, obtaining a much greater total length of working edges than ever before from a given amount of stone. The stone itself was normally a homogeneous easily-worked type such as chert or obsidian.

Loren Eiseley has worked out a helpful summery of this increasing efficiency, estimated assuming the use of 500g ( 1 Ib 1 oz) of high-quality chert:

This trend toward greater economy reached its peak in the Mesolithic, around 10,000 years ago, with the rise to dominance of microliths, tiny stone tools many of which were probably used as barbs on composite weapons.

The types of tools found at a site can also provide clues to the site’s function: a hunting kit with projectile points might be expected in a temporary camp or a permanent settlement.

Some techniques of manufacture can be inferred from traces left on the tools, and many techniques can still be observed among the few living peoples, such as some Australian or highland of Maya.

There are two principal approaches to assessing what decisions the knapper made: Replication and Refitting

Stone Tool Replication

This is a type of experimental archaeology that involves making exact copies of different types of stone tool – using only the technology available to the original makers – in order to assess the processes entailed, and the amount of time and effort required. In the past only remarkable work has done by Francois Bordes in the Old World and Donald Crabtree in New World.

American archaeologist Nicholas Toth, for example, has made and used the entire range of early stone tools, as found at sites such as Koobi Fora, Kenya, and dating to about 1.5 to 2 million years ago- hammer stone, choppers, scrapers, and flakes. His work provides evidence to suggest that simple flakes may have been the primary tools, while the more impressive cores were an incidental by - product of flake manufacture. Previously, scholars tended to see the flakes as waste products and the cores as the intentional end – product.

Donald Crabtree was able to solve one specific problem that the Paleo - Indians of North America had made their fluted stone tools known as Folsom points, dating to some 11,000 – 10,000 years ago. In particular, how had they managed to remove the “flute” or channel flake?

The correct method, as new experiments proved, involves pressing the flake out, downwards, by means of a T – shaped crutch placed against the chest; the crutch’s tip is forced down against a precise point on the core which is clamped firm.

Archaeologist can also use replication and experiment to discover whether certain flint tools had been deliberately heated during manufacture. Purdy and Brooks investigated the differences between unheated and heated chert. Petro- graphic thin – sections failed to detect any differences in structure, but in the scanning electron microscope it became clear that heated chert had a far smoother appearance. Furthermore, a study of rock mechanics showed that after heating chert had an increase in compressive strength of 25 – 40 percent, but a decrease of 45percent in the force needed to break it.

Replication cannot usually prove conclusively which techniques were used in the past, but it does narrow the possibilities and often points to the most likely method, as in the Folsom example above. Refitting, on other hand, involves working with the original tools and demonstrates clearly the chain of actions of the knapper.

Refitting of Stone Tools

This type of work, which can be traced back to F. C. J.Spurrell at the Paleolithic site of Crayford, England, in 1880, has really come into its own efforts of Andre Leroi –Gourhan at the Megdalenian (Late Upper Paleolithic) camp of Pincevent, Paris.

Refitting, or conjoining as it is sometimes called, entails attempting to put tools and flakes back together again, like a 3-D jigsaw puzzle. The work is tedious and time – consuming, but can produce spectacular results.

Refitting allows us to follow the stages of the knapper’s craft and – where pieces from one core have been found in different areas – even the knapper’s (or the core’s) movement around the site.

Refitting provides a dynamic perspective on the spatial distribution of tools, and produces a vivid picture of actual movement and activity in an ancient site. Where these observations can be supplemented by information on the functions of the tools, the site really comes to life.