How did ancient stone masons (greeks etc) produce columns of such perfect symmetry and smoothness ?
Good symmetry is easily achieved, essentially they had measuring tools as good as ours. A piece of string fixed at one end produces a perfect circle, a plumb line a perfect vertical line and a translucent tube filled with water (and held in horseshoe fashion) gives a perfect horizontal line. Combine the last two and you also have a perfect right-angle. Use the same marked up piece of string several times & you produce several identical pillars. As someone has suggested these columns were usually made in sections, so this made the process simpler in terms of the mass handled. Where columns were fluted (or similar) this detail would normally be added after two or more sections have been rough hewn and fitted together – running flutes seamlessly together cannot reliably be done by other methods.
Speaking specifically of the Greeks, they used a variety of techniques to carve columns. As a previous poster said, large columns were composed of multiple drums, though smaller columns could be made of a single piece of stone (like those of the Nike temple on the Athenian acropolis). Carvings were done in stages, with a rough finish being left on the stone until the columns were actually in place. After that the final finish would be done by very minute cuttings and polishing. If a piece was damaged during carving it could be individually discarded and recut; this way the entire column wasn’t ruined. Some ancient Greek monuments were never entirely finished and the rough protective stage was left unfinished. Check out the stones on the propylaeum in Athens if you ever get the chance, you’ll see that they aren’t completely polished and that some “handles” have been left on the blocks that would have been used to lift them into place. The Stoa of Attalos in the Athenian agora was comple
