There’s a question that’s been bothering me for some time. Many flint human artefacts show evidence of retouching to the edges, apparently either to blunt them, to make them easier to hold, or to sharpen them. But why exactly would anyone want to sharpen the edge of a flint flake or blade? If you strike a flake or blade from a core, you get an object which usually has a continuous edge that is – literally – sharper than a razor. Flint can take an edge that it only a few molecules thick, far thinner and sharper than the finest steel, which is why flint is still used today by some surgeons for their scalpels. So why mess up a near perfect cutting edge by retouching it with an antler tine or bone point? I can understand if the aim is to make a denticulate saw-blade for cutting through wood, but not for the vast majority of flint tools – knives, scrapers, axes, adzes and the like. Has anyone done any comparative trial experimentally on this issue?
Why would anyone want to retouch a flint tool?
10 Thursday Jan 2013
Posted in Stone age tools
The Museum of The Stone Age 
Richard, Observations of modern-day usage of napped flint and obsidian reveals a tendency to abuse their fine edges. Dragging a razor sharp edge across an animal skin would likely not dull the edge, excessive pressure, though, can crush that fine edge destroying its sharpness. It became necessary on occasion to sharpen the stone edges.
A un-retouched edge will break and/or dull very easily. Any tool meant for long-term use will be pressure flaked along it’s usable edge. Flake tools with unre-touched edges were “throw-away” items. When they dulled, they were discarded, or re-touched for further use. FGurther, most tools or points we find are at the end of their use lives. They have be re-sharpened or repaired to the point where their functionality is exausted. The original item many have looked much different.