Peter Lynn ARCHIVE
The development of saws for cutting wood was a significant technological step in human- and pre-human- history. The first saws- jaw bones and serrated flints- existed before ‘modern’ humans appeared. Post Neolithic, much better bronze saws came into use, but for cutting planks, saws didn’t challenge splitting with axes and wedges until the Iron Age. Iron saws are known from around 1500BCE in Egypt and 500BCE in China.
Wrought iron and (later) steel hand saws that are not significantly different to current styles (pull and push) have now been in use in the East and the West for more than 2000 years.
With these, until quite recent times, the usual method for turning trees into useable timber has been pit sawing: A log is positioned above a pit while one person below and another above use a double ended saw to cut it lengthwise into boards. Even in the 21st century, pit sawing is still used in some undeveloped areas, 10 planks a day being a reasonable output.
The first reference to the application of water power for sawing is a 3rd century Roman reciprocating vertical water powered mill at Hierapolis (present day Turkey), but this was used to cut marble not wood.
By the 11th century, vertical reciprocating water powered wood cutting saw mills were in use in Islamic North Africa, Central Asia and Spain – and there are references to one in Normandy (France) at this date also. The application of wind power to sawmilling, never widespread, seems to have been a 16th century Dutch invention- big surprise!
But most early mills used water power and were built on site by millwrights with local materials, metals being used only for critical components. Typically they were located adjacent to suitable stands of timber, and were abandoned or moved when these were cut out – except where water transport could be used to bring logs from a wider catchment.
Vertical reciprocating saws could easily cut 10 times as much timber per day per person as pit sawing, so were soon established wherever a suitable head of water was available. New Zealand’s first powered sawmill, at Mercury Bay, Coromandel, in 1838, was of this type.
Reciprocating saws that can cut 1m diameter logs require around 4 Kw, while circular rigs need at least 10 times this, but can be > 100 times more productive. The circular saw principle has been known since at least Grecian times but couldn’t be used for log sawing until >40kw steam engines became available by the later 19th century. The even more efficient bandsaws had also been known since classical times but didn’t become truly reliable until the development of nickel alloy steels in the early 20th century.
Stand-alone horizontal reciprocating mills like the Wehrhahn, usually steam powered, were a late arrival on the sawmilling scene, unable to compete with circular saws and bandmills except for one man operations supplying local users, often seasonally.
PETER LYNN, ASHBURTON NEW ZEALAND, SEPTEMBER ‘15
